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User’s Manual

2750-900-01 Rev. F / August 2011

Model 2750

Multimeter/Switch System

Summary of content (452 pages)

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w w w . k e i th l e y. c o m Model 2750 Multimeter/Switch System User’s Manual 2750-900-01 Rev.
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750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual 2011, Keithley Instruments, Inc. All rights reserved. Cleveland, Ohio, U.S.A. Document Number: 2750-900-01 Rev.
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2750-900-01.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM Safety Precautions 04/09 The following safety precautions should be observed before using this product and any associated instrumentation. Although some instruments and accessories would normally be used with non-hazardous voltages, there are situations where hazardous conditions may be present.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM themselves from the risk of electric shock. If the circuit is capable of operating at or above 1000V, no conductive part of the circuit may be exposed. Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedancelimited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault current and voltage to the card.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM The WARNING heading in the user documentation explains dangers that might result in personal injury or death. Always read the associated information very carefully before performing the indicated procedure. The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such damage may invalidate the warranty. Instrumentation and accessories shall not be connected to humans.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM Table of Contents 1 Getting Started General information ................................................................................. 1-2 Contact information .......................................................................... 1-2 Safety symbols and terms ................................................................. 1-2 Inspection ..........................................................................................
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 2-wire functions ................................................................................. 2-8 4-wire functions (paired channels) .................................................... 2-8 Controlling the system channel ......................................................... 2-9 Non-amp and non-measure switching modules .............................. 2-13 Multiple channel operation ............................................................
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Thermistors ..................................................................................... 4-wire RTDs .................................................................................... Connections .................................................................................... Temperature measurement configuration ........................................ Temperature measurement procedure .............................................
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM Relative ..................................................................................................... 5-2 Basic operation .................................................................................. 5-2 Remote programming — rel ............................................................. 5-4 Math .......................................................................................................... 5-8 mX+b .......................
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Manual/external trigger scan ........................................................... Monitor scan (analog trigger) ......................................................... Remote programming — scanning ........................................................ Trigger model .................................................................................. Channel setup ..............................................................................
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM Limits .............................................................................................. 9-16 Digital outputs ................................................................................. 9-18 10 Remote Operations Operation enhancements ........................................................................ 10-2 Pseudocards ..................................................................................... 10-2 Autozero .......
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Error messages .............................................................................. 10-21 11 Status Structure Overview ................................................................................................ 11-2 Status byte and SRQ ....................................................................... 11-2 Status register sets ........................................................................... 11-2 Queues ..............
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM SYSTem:BEEPer[:STATe] ..................................................... 14-8 15 SCPI Reference Tables Reference tables ...................................................................................... 15-2 B Model 7700 Connection Guide Card configuration — schematic ............................................................. B-2 Connections and wiring ...........................................................................
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Source resistance noise ..................................................................... E-5 Magnetic fields .................................................................................. E-6 Radio frequency interference ............................................................ E-6 Ground loops ..................................................................................... E-7 Shielding .............................................
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 1 Getting Started Quick Start — Of the following section topics, three can be used immediately to quickly acquaint yourself with fundamental instrument operations. Use QS1 to familiarize yourself with front panel controls, use QS2 to power-up the instrument, and, finally, use QS3 to perform exercises to operate the instrument.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 1-2 Getting Started Model 2750 Multimeter/Switch System User’s Manual General information Contact information Worldwide phone numbers are listed at the front of this manual. If you have any questions, please contact your local Keithley representative or call a Keithley Application Engineer at 1-800-348-3735 (U.S. and Canada only).
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-3 Inspection Model 2750 was carefully inspected electrically and mechanically before shipment. After unpacking all items from the shipping carton, check for any obvious signs of physical damage that may have occurred during transit. (There may be a protective film over the display lens, which can be removed). Report any damage to the shipping agent immediately.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 1-4 Getting Started Model 2750 Multimeter/Switch System User’s Manual Model 7703 — This differential multiplexer provides 32 channels of 2-pole input, or 16 channels of 4-pole input. Model 7705 — This control module provides 40 independent 1-pole switching (SPST) channels that are isolated from the internal DMM.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-5 Rack mount kit Model 4288-7 rack mount kit — Mounts a Model 2750 in a standard 19-inch rack. Includes rear brackets to provide additional support for a mainframe that has two or more switching modules installed. NOTE The Model 2750 includes hardware that allows it to be mounted to the front rails of a standard 19-inch rack.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 1-6 Getting Started • • • Model 2750 Multimeter/Switch System User’s Manual Digital I/O port — Five digital limit test output lines to control external circuitry. The digital trigger link and hardware interlock input can also be accessed at this port. Monitor — The Model 2750 can monitor a selected channel. A scan can be triggered to start when the Monitor detects a reached reading limit.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 1-8 Getting Started Model 2750 Multimeter/Switch System User’s Manual Pseudocards Using remote programming, you can assign a pseudocard to an empty switching module slot. With a pseudocard “installed,” the Model 2750 will operate as if the switching module is installed in the Model 2750. This feature allows you to configure your system without having the actual switching module installed in the unit.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-9 Front and rear panel familiarization Front panel summary The front panel of Model 2750 is shown in Figure 1-1.
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50-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 1-10 Getting Started Middle Row Unshifted EXTRIG TRIG STORE RECALL FILTER REL and Shifted DELAY DRYCKT LIMITS ON/OFF TYPE MONITOR CH-OFF CARD Bottom Row Unshifted OPEN CLOSE STEP SCAN DIGITS RATE EXIT ENTER Shifted SAVE SETUP CONFIG HALT TEST LSYNC GPIB RS-232 Model 2750 Multimeter/Switch System User’s Manual Selects external triggering (front panel, bus, trigger link) as the trigger source.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-11 4 Display annunciators: * (asterisk) ↔ (more) ))) (speaker) 4W DCKT ~AC AUTO BUFFER CHAN DELTA ERR FAST FILT HIGH LSTN LOW MATH MED MON OCOMP RATIO REAR REL REM SCAN SHIFT SLOW SRQ STAT STEP TALK TIMER TRIG Readings being stored in buffer. Indicates additional selections are available. Beeper on for continuity or limits testing.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 1-12 Getting Started Model 2750 Multimeter/Switch System User’s Manual Rear panel summary The rear panel of Model 2750 is shown in Figure 1-2. As shown, slot covers are installed on unused slots. WARNING Slot covers must be installed on unused slots to prevent personal contact with high voltage circuits. Figure 1-2 Model 2750 rear panel 1 2 3 4 ! DIGITAL I/O TRIG. LINK RS-232 KEITHLEY SLOT COVER IEEE-488 SLT 1 MADE IN U.S.A.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-13 Rack mounting The Model 2750 can be mounted in a standard 19-inch rack. For a mainframe that has one or no switching modules installed, the Model 2750 can be secured to the front rails of the rack. The hardware necessary to secure the mainframe to the front rails of the rack is supplied with the Model 2750.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 1-14 Getting Started Model 2750 Multimeter/Switch System User’s Manual Power-up Line power connection Follow the procedure below to connect the Model 2750 to line power and turn on the instrument. 1. Check to see that the line voltage indicated in the window of the fuse holder assembly (Figure 1-4) is correct for the operating voltage in your area. If not, refer to the next procedure, “Setting line voltage and replacing fuse,” page 1-15.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-15 Line frequency The Model 2750 will operate at line frequencies from 45Hz to 66Hz, and 360Hz to 440Hz. There are no user-settings for line frequency. It is automatically sensed at power-up. The following command can be used to read the line frequency: SYSTem:LFRequency? ' Query power line frequency.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 1-16 Getting Started Model 2750 Multimeter/Switch System User’s Manual Power-up sequence On power-up, the Model 2750 performs self-tests on its EPROM and RAM and momentarily lights all segments and annunciators. If a failure is detected, the instrument momentarily displays an error message and the ERR annunciator turns on. (Error messages are listed in Appendix C).
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-17 Remote programming The following command controls keyclick: SYSTem:KCLick ' Enable or disable keyclick. where: = ON or OFF NOTE Keyclick ON is the FACTORY, *RST, and SYSTem:PRESet default. Display Readings are displayed in engineering units (i.e., 100.23mV), while annunciators indicate various states of operation.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 1-18 Getting Started DISPlay:TEXT:DATA Model 2750 Multimeter/Switch System User’s Manual Define text message This command defines the text message for display. A message can be as long as 12 characters. A space counts as a character. Excess message characters results in an error. The characters must be enclosed in either single quotes (‘ ’) or double quotes (“ ”).
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-19 Defaults and user setups Model 2750 can be restored to one of two default setup configurations (FACTory or *RST), or three user-saved (SAV0, SAV1, or SAV2). As shipped from the factory, Model 2750 powers up to the factory (FACT) default settings. NOTE Closed channels can be saved in a user setup (SAV0, SAV1, or SAV2).
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 1-20 Getting Started Model 2750 Multimeter/Switch System User’s Manual Saving and restoring setups Saving a user setup 1. 2. 3. 4. Configure Model 2750 for the desired measurement application. Press SHIFT and then SAVE to access the save setup menu. Press to place the cursor on the present setup (SAV0, SAV1, or SAV2). Use the Δ or ∇ key to display the desired setup and press ENTER. The instrument returns to the normal measurement state.
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2750-900-01.book Page 24 Wednesday, August 3, 2011 7:56 AM 1-24 Getting Started Model 2750 Multimeter/Switch System User’s Manual Table 1-4 (continued) Default settings Setting Factory Voltage (AC and DC) dB Reference Digits (AC) Digits (DC) Filter Window Count Type Range Rate (DC) Rel Off 1.0 5Hdigits 6Hdigits On 0.1% 10 Moving Auto Slow (5 PLC) Off *RST Set Diff Off 1.0 5Hdigits 6Hdigits Off 0.
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2750-900-01.book Page 25 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-25 Programming example *SAV 2 SYST:POS SAV2 *RST *RCL 2 ' ' ' ' Save present setup in memory location 2. Specify SAV2 setup as the power-on setup. Return 2750 to RST defaults. Return 2750 to setup stored in memory location 2. Remote programming information Remote programming information is integrated with front panel operation throughout this manual.
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2750-900-01.book Page 26 Wednesday, August 3, 2011 7:56 AM 1-26 Getting Started NOTE Model 2750 Multimeter/Switch System User’s Manual When using the front panel input terminals, the INPUT switch must be in the “F” (out) position. The INPUT switch is located on the right side of the front panel near the input terminals. When using a switching module, the switch must be in the “R” (in) position. Basic DMM measurements — front panel inputs NOTE See Section 3 for details on basic DMM operation.
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2750-900-01.book Page 27 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-27 The following examples demonstrate how to include the function name in the command string for configuration commands. VOLT:RANG 10 RES:RANG:AUTO ON CURR:DIG 4.5 NOTE ' ' ' Select 10V range for DCV. Enable auto range for W2. Set DCI for 4½- digit resolution. See Section 4 for details on setting range, digits, rate, bandwidth, and filter.
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2750-900-01.book Page 28 Wednesday, August 3, 2011 7:56 AM 1-28 Getting Started Model 2750 Multimeter/Switch System User’s Manual Closing and opening channels — system channel operation NOTE See Section 2 for details on closing and opening switching module channels. NOTE The following discussion assumes a multiplexing switching module (i.e., Model 7700) installed in slot 1 of the mainframe. Switching module installation is covered in “Switching module installation and connections,” page 2-3.
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2750-900-01.book Page 29 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-29 Figure 1-6 Connection to DMM for 4-wire function (system channel 106 closed) 7700 Switching Module HI 7700 Switching Module HI HI Input Ch 6 Ch 6 LO LO HI Input LO LO DUT DMM HI HI Sense Ch 16 LO LO NOTE DMM HI Ch 16 HI Sense LO LO Switching module channels can also be controlled using multiple channel operation.
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2750-900-01.book Page 30 Wednesday, August 3, 2011 7:56 AM 1-30 Getting Started Model 2750 Multimeter/Switch System User’s Manual Figure 1-7 Front panel keys to close and open system channels Close next measurement channel OPEN CLOSE CLOSE:SINGLE Close previous measurement channel Press CLOSE key Display SINGLE option and press ENTER OPEN CLOSE Press OPEN key OPEN: ALL Display ALL option and press OPEN again Specify channel CLOSE CH: XXX number (XXX) and press ENTER A.
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2750-900-01.book Page 31 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-31 Exercise 2 — Closing and opening channels (system channel operation) The exercise in Table 1-7 demonstrates a sequence to close and open channels of a Model 7700 installed in slot 1 of the mainframe.
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2750-900-01.book Page 32 Wednesday, August 3, 2011 7:56 AM 1-32 Getting Started Model 2750 Multimeter/Switch System User’s Manual Timer interval (TIMER) — For the STEP function, the timer specifies the time delay between scanned channels. For the SCAN function, the interval specifies the time delay between scans. The timer starts when the scan is started. For SCAN, the next scan will not start until the timer interval expires. NOTE The Model 2750 can also be configured to run an advanced scan.
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2750-900-01.book Page 33 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-33 For remote programming, the following commands are used for simple scanning: ROUTe:SCAN TRIGger:COUNt ' ' ' SAMPle:COUNt ' ' ROUTe:SCAN:LSELect ' Define scan list*. Specify number of scans (1 to 11000 or INFinity). Specify number of channels to scan (1 to 11000). Enable (INT) or disable (NONE) scan.
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2750-900-01.book Page 34 Wednesday, August 3, 2011 7:56 AM 1-34 Getting Started Model 2750 Multimeter/Switch System User’s Manual Trigger and return readings — remote programming There are several commands used to trigger and return readings. The proper commands and sequence to use depend on trigger state (continuous or non-continuous) and what you are trying to accomplish. Presented here are three fundamental command sequences that can be used to “trigger and return readings.
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2750-900-01.book Page 37 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-37 Figure 1-11 Exercise 6 — Return a single reading (continuous triggering) Trigger Configuration Return Readings SAMP:COUN 1 INIT:CONT ON FETCh? OR CALC:DATA? Place 2750 in continuous trigger state. DATA? OR DATA:FRESh? Return Basic Reading2, 3 Return result of MATH Calculation1, 2 1.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 2 Closing and Opening Switching Module Channels • Close/open overview — Summarizes the two operating modes to control switching modules: system channel operation and multiple channel operation. • Switching module installation and connections — Explains how to install a switching module (or pseudocard) into the Model 2750 mainframe. Also explains where to find connection information which should only be performed by qualified service personnel.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 2-2 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Close/open overview NOTE This section covers basic close/open operations for switching module channels. It also covers the operating characteristics that are unique to the Model 7700 switching module. Unique operating characteristics for all switching modules are provided in the Model 77XX Series Switching Modules Instruction Manual.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-3 Switching module installation and connections In order to exercise close/open operations explained in this section, a switching module (or pseudocard) must be installed in the mainframe. A switching module can be installed by the user, however external connections to the switching module are only to be performed by qualified service personnel.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 2-4 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Connections WARNING Connection information for switching modules is intended for qualified service personnel. Do not attempt to connect DUT or external circuitry to a switching module unless qualified to do so.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-5 Pseudocards Using remote programming, you can assign a pseudocard to an empty switching module slot. With a pseudocard installed, the Model 2750 will operate as if the switching module is installed in the Model 2750.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 2-6 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual System channel operation The system channel is a closed measurement channel that is internally connected to the internal DMM Input of the Model 2750. The system channel number is displayed on the Model 2750. For a 4-wire function (i.e., Ω4), the paired channel for the system channel is internally connected to DMM Sense.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-7 2-wire functions Figure 2-1 shows an example of how the system channel is connected to the DMM Input of the Model 2750. Assume a Model 7700 switching module is installed in slot 1 of the mainframe.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual NOTE Close/Open Switching Module Channels 2-9 The and keys can also be used to open all channels in the mainframe. Simply increment or decrement the channel number until there is no channel displayed.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 2-10 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual TOO SMALL or TOO LARGE — These messages also indicate an invalid channel. TOO SMALL indicates that the specified channel and any other lower numbered channel is invalid. TOO LARGE indicates that the specified channel and any other higher numbered channel is invalid.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-11 Remote programming — system channel control commands The commands to close and open the system channel are listed in Table 2-1. When a system channel reading is returned, the system channel number will be included in the data string if the CHANnel data element is selected.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 2-12 Close/Open Switching Module Channels c. d. Model 2750 Multimeter/Switch System User’s Manual ROUTe:CLOSe? This query command returns a of closed measurement channels, including paired channels for 4-wire functions. This query command will not return non-measurement channels, such as backplane isolation channels and the pole-mode channel. ROUTe:OPEN:ALL This command functions the same as the front panel OPEN key (ALL menu option).
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-13 If a system channel is already closed and you attempt to select the DCI or ACI function, the message “INVALID FUNC” will be displayed briefly. For remote programming, error -221 (Settings conflict) is generated. Example: SYST:PRES ROUT:CLOS (@101) SENS:FUNC ‘CURR:DC’ ' ' ' ' Restores system preset defaults. Close system channel 101.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 2-14 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Making amps measurements — In order to perform amps measurements, you must use the front panel inputs of the 2701 mainframe. You can still use the non-amps module for other aspects of the test, but you must use multiple channel operation to close channels.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-15 isolation channels. Multiple channel operation should only be performed by experienced test system engineers. WARNING NOTE Careless multiple channel operation could create an electric shock hazard that could result in severe injury or death. Improper operation can also cause damage to the switching modules and external circuitry.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 2-16 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Some other key points for multiple channel operation include the following: • • • NOTE Closing a channel using multiple channel operation has no affect on other closed channels. Whatever channels were previously closed, remain closed. A channel closed using multiple channel operation is not displayed on the Model 2750.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-17 CLOSE key (MULTI menu option) The MULTI menu option for the CLOSE key can be used to close any individual channel in the mainframe (Figure 2-6). Perform the following steps to close a channel: NOTE 1. 2. 3. 4. Channels closed by the MULTI option of the CLOSE key are not displayed.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 2-18 Close/Open Switching Module Channels 3. 4. 5. NOTE Model 2750 Multimeter/Switch System User’s Manual Press ENTER to display the prompt to open a channel (OPEN MLT:XXX). Using , , Δ , and ∇ , key in the three-digit channel you want to select. Press ENTER to open the channel.
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-19 Reference: a. ROUTe:MULTiple:CLOSe This command functions like the front panel CLOSE key (MULTI menu option) to close channels. When you send this command to close the channels specified in the , only those listed channels will close. Channels not specified are not affected, and channel pairing is disabled.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 2-20 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Remote programming example (multiple channel operation) The following example assumes a Model 7700 installed in slot 1. This command sequence connects channel 101 to channel 111 (through channel 123). Note that these two closed channels will be internally isolated from the DMM since the backplane isolation channels (124 and 125) will be open.
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2750-900-01.book Page 21 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-21 To correctly display the channel that is closed (channel 102) repeat step 1 above to open all channels, and then use the key or the ROUT:CLOS (@102) command to close (and display) channel 102. This closes channel 102 (which is the system channel) and channel 125 to connect it to the DMM Input.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 2-22 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Dual independent multiplexers Using multiple channel operation, any multiplexer switching module can be configured as two independent multiplexers. For example, the Model 7700 is normally used as a single 1 × 20 multiplexer, but it can also be configured as two 1 × 10 multiplexers.
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2750-900-01.book Page 23 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-23 Dual multiplexer application This application demonstrates how to use the Model 7700 as a dual multiplexer to bias and measure 10 DUT. An external source powers the DUT, while the DMM of the Model 2750 measures the output of the DUT. To prevent overloading of the external source, each DUT is powered (and measured) separately.
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2750-900-01.book Page 25 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-25 Test procedure: NOTES The following test procedure assumes a Model 7700 switching module installed in slot 1 of the mainframe. The procedure assumes that the instrument is operating in the continuous measurement (triggering) mode (see “Defaults and user setups,” page 1-19).
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2750-900-01.book Page 26 Wednesday, August 3, 2011 7:56 AM 2-26 Close/Open Switching Module Channels 7. 8. Model 2750 Multimeter/Switch System User’s Manual Test the remaining eight DUT in a similar manner. That is, close the appropriate channels for the DUT, make the measurement, and then open the channels. After the last DUT is tested, repeat step 1 to open all channels.
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2750-900-01.book Page 27 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-27 Identifying installed modules and viewing closed channels On power-up, the model numbers of installed switching modules are displayed briefly. While in the normal display state, red slot indicators on the right side of the display indicate which slots have a switching module or pseudocard installed.
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2750-900-01.book Page 28 Wednesday, August 3, 2011 7:56 AM 2-28 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual CARD: CONFIG — This menu item is used to configure switching modules. The channels of the Model 7700 switching module and other similar type modules do not need to be configured. SLOTX: 77xx — Use to configure the switching module in Slot X (where X = 1, 2, 3, 4, or 5).
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2750-900-01.book Page 29 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-29 Figure 2-11 CARD menu tree SHIFT CARD VIEW CONFIG SLOT1: 77XX SLOT5: 77XX 77XX = Model number of installed switching module. SLOT1: 77XX SLOT5: 77XX Scrolls Channels Scrolls Channels Switching module queries (remote operation) For remote operation there are commands to identify installed switching modules and channels that are closed.
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2750-900-01.book Page 30 Wednesday, August 3, 2011 7:56 AM 2-30 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual ROUTe:CLOSe? ROUTe:MULTiple:CLOSe? ROUTe:MULTiple:CLOSe:STATe? These query commands are used to determine closed switching module channels. ROUT:CLOS? is used to return a list of closed measurement channels including the paired channel for 4-wire measurements. It will not return non-measurement channels.
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2750-900-01.book Page 31 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-31 Relay closure count The Model 2750 keeps an internal count of the number of times each module relay has been closed. The total number of relay closures are stored in EEPROM on the card. This count will help you determine if and when any relays require replacement (see module contact life specifications).
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2750-900-01.book Page 32 Wednesday, August 3, 2011 7:56 AM 2-32 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual Reading relay closure count To determine the closure count of specific channels, send this query via remote: ROUTe:CLOSe:COUNt? Here, is the summary of channels.
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2750-900-01.book Page 33 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-33 Model 7700 switching module NOTE Connection and wiring procedures for the Model 7700 are to be performed by qualified service personnel. This information is provided in Appendix B (Model 7700 Connection Guide).
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2750-900-01.book Page 34 Wednesday, August 3, 2011 7:56 AM 2-34 Close/Open Switching Module Channels • • • • CH2 and CH12 CH3 and CH13 CH4 and CH14 CH5 and CH15 Model 2750 Multimeter/Switch System User’s Manual • • • • CH7 and CH17 CH8 and CH18 CH9 and CH19 CH10 and CH20 Schematic diagram The simplified schematic diagram of the Model 7700 is shown in Figure 2-12. Channels 1 through 20 are used for all measurements except amps. Channels 21 and 22 are used for amps only.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 3 Basic DMM Operation • DMM measurement capabilities — Summarizes the measurement capabilities of the Model 2750 and covers maximum signal levels for switching modules. • High energy circuit safety precautions — Provides safety information when performing measurements in high energy circuits. • Performance considerations — Covers some considerations that affect overall performance including warm-up, autozero, and line synchronization.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 3-2 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual DMM measurement capabilities The DMM of the Model 2750 can make the following measurements: DCV — DC voltage measurements from 0.1µV to 1000V. ACV — AC voltage measurements from 0.1µV to 750V. DCI — DC current measurements from 10nA to 3A. ACI — AC current measurements from 1µA to 3A. Ω2 — 2-wire resistance measurements from 10µΩ to 120MΩ.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-3 High energy circuit safety precautions To optimize safety when measuring voltage in high energy distribution circuits, read and use the directions in the following warning. WARNING Dangerous arcs of an explosive nature in a high energy circuit can cause severe personal injury or death.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 3-4 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Performance considerations Warm-up After the Model 2750 is turned on, it must be allowed to warm up for at least two hours to allow the internal temperature to stabilize. If the instrument has been exposed to extreme temperatures, allow extra warm-up time.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-5 LSYNC (line cycle synchronization) Synchronizing A/D conversions with the frequency of the power line increases common mode and normal mode noise rejection. When line cycle synchronization is enabled, the measurement is initiated at the first positive-going zero crossing of the power line cycle after the trigger.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 3-6 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Remote programming — autozero and LSYNC Autozero and LSYNC commands The commands to control display resolution (digits) are listed in Table 3-1.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-7 Channel list parameter () Channels of one or more switching modules installed in the Model 2750 can be scanned. Each scan channel can have its own unique setup. For example, a channel could be set to measure DCV on the 10V range, while another channel can be set to measure ACV on the 1V range.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 3-8 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Voltage measurements (DCV and ACV) The Model 2750 can make DCV measurements from 0.1µV to 1000V and ACV measurements from 0.1µV to 750V RMS, 1000V peak.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-9 Front panel input When using the front panel input terminals, connect the test leads to the INPUT HI and LO terminals as shown in Figure 3-2.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 3-10 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Model 7700 switching module Connections for the Model 7700 switching module are shown in Figure 3-3. For basic DCV and ACV measurements (Figure 3-3A and B), channels 1 through 20 can be used. Ratio and channel average calculations — Ratio calculates the reading ratio of two channels, while channel average calculates the reading average of two channels.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-11 Volts measurement procedure NOTE 1. 2. 3. 4. Make sure the INPUTS switch is in the correct position. To use front panel inputs, it must be in the “F” (out) position. For switching modules, it must be in the “R” (in) position. If a switching channel is presently closed (displayed), press OPEN to open it. Select the volts measurement function by pressing DCV or ACV.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 3-12 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Crest factor AC voltage (and current) accuracies are affected by the crest factor of the waveform, the ratio of the peak value to the RMS value. Table 3-2 lists the fundamental frequencies at which the corresponding crest factor must be taken into account for accurate calculations.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-13 Thermal EMFs Thermal EMFs (thermoelectric potentials) are generated by temperature differences between the junctions of dissimilar metals. These can be large compared to the signal that the Model 2750 can measure. Thermal EMFs can cause the following conditions: • • Instability or zero offset is much higher than expected.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 3-14 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Current measurements (DCI and ACI) The Model 2750 can make DCI measurements from 10nA to 3A and ACI measurements from 1µA to 3A RMS. NOTE See the previous discussion about crest factor in “Voltage measurements (DCV and ACV),” page 3-8. Connections NOTE When using the front panel inputs, the INPUTS switch must be in the “F” (out) position.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-15 Model 7700 switching module Connections for the Model 7700 switching module are shown in Figure 3-5. Note that only channels 21 and 22 can be used for current measurements.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 3-16 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual AMPS fuse replacement (front panel AMPS input) WARNING 1. 2. 3. Turn off the power and disconnect the power line and test leads. From the front panel, gently push in the AMPS fuse holder with a flat blade screwdriver and rotate the fuse holder one-quarter turn counterclockwise. Remove the fuse and replace it with the same type (3A, 250V, fast-blow, 5 × 20mm).
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-17 Connections NOTE When using the front panel inputs, the INPUTS switch must be in the “F” (out) position. For switching modules, it must be in the “R” (in) position. Front panel inputs Connections for resistance measurements are shown in Figure 3-6. For 2-wire resistance measurements (Ω2), connect the test leads to INPUT HI and LO as shown in Figure 3-6A.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 3-18 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Figure 3-6 Ω2 and Ω4 connections for front panel inputs Model 2750 Front Panel SENSE Ω 4 WIRE Shielded Cable INPUT HI 350V PEAK 1000V PEAK ! LO Resistance Under Test 500V PEAK INPUT F Optional Shield R FRONT/REAR AMPS CAT I 3A, 250V A. Ω2 Connections Note: Source current flows from the INPUT HI to INPUT LO terminals.
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-19 Figure 3-7 Ω2 and Ω4 connections for Model 7700 switching module H Model 7700 Switching Module Shielded Cable Optional Shield Resistance Under Test CH 1-20 L A.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 3-20 Basic DMM Operation CAUTION Model 2750 Multimeter/Switch System User’s Manual Front panel inputs — Do not apply more than 1000V peak between INPUT HI and LO, or instrument damage may occur. Model 7700 switching module — Do not apply more than 300V DC or RMS between input high (H) or input low (L), or switching module damage may occur. 5. If using a switching module, perform the following steps to close the desired channel.
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2750-900-01.book Page 21 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-21 The offset-compensated ohms reading is then calculated as follows: Offset-compensated ohms reading = ΔV/ΔI where: ΔV = V2 - V1 ΔI = I2 - I1 V1 is the voltage measurement with the current source at its normal level. V2 is the voltage measurement using the lowest current source setting.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 3-22 Basic DMM Operation NOTE Model 2750 Multimeter/Switch System User’s Manual The OCOMP annunciator will flash when the instrument is on an invalid range (100kΩ through 100MΩ ranges) for offset-compensated ohms. Normal ohms measurements will instead be performed. With dry circuit ohms enabled, 1kΩ is the highest offset-compensated ohms range that can be selected.
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2750-900-01.book Page 23 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-23 Measuring resistance of voltage-sensitive devices Dry circuit ohms should be used for any device that could be damaged by high opencircuit voltage. If not sure, and the slightly degraded accuracy is not a consideration, it is good practice to use dry circuit ohms to measure low resistance.
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2750-900-01.book Page 24 Wednesday, August 3, 2011 7:56 AM 3-24 Basic DMM Operation NOTE Model 2750 Multimeter/Switch System User’s Manual The states (on or off) of dry circuit ohms and offset-compensated ohms are “remembered” by the Ω4 function after you select a different measurement function (i.e., DCV). When Ω4 is again selected, the previous states of dry circuit ohms and offset-compensated ohms will be restored.
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2750-900-01.book Page 25 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-25 Temperature measurements The Model 2750 can measure temperature using thermocouples, thermistors, and 4-wire RTDs. When deciding which temperature sensor to use, keep in mind that the thermocouple is the most versatile, the thermistor is the most sensitive, and the 4-wire RTD is the most stable.
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2750-900-01.book Page 26 Wednesday, August 3, 2011 7:56 AM 3-26 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Reference junctions A reference junction is the cold junction in a thermocouple circuit which is held at a stable, known temperature. It is at the cold junction where dissimilar wire connections must be made.
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2750-900-01.book Page 27 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-27 External reference junction For switching modules that do not have built-in sensors to measure temperature, each module can use a thermistor or 4-wire RTD to acquire the reference temperature. Connect a thermistor to channel 1 or connect a 4-wire RTD to channel 1 and its paired channel.
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2750-900-01.book Page 28 Wednesday, August 3, 2011 7:56 AM 3-28 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual 4-wire RTDs For 4-wire RTDs, the temperature measurement range is -200°C to 630°C (0.01°C resolution). RTD types that are supported include D100, F100, PT385, and PT3916. A USER type is available to modify RTD parameters, such as the resistance at 0°C. The USER type can be enabled from the front panel, but the settings can only be changed using remote programming.
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2750-900-01.book Page 29 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-29 ence junction may be inconvenient but it will provide more accurate temperature measurements (assuming the user enters a precise reference temperature). With open thermocouple detection disabled, the Model 2750 can calculate the average temperature of two thermocouple channels using Channel Average (see Section 5 for details).
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2750-900-01.book Page 30 Wednesday, August 3, 2011 7:56 AM 3-30 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Figure 3-8 Thermocouple connections Model 2750 Input HI + Input LO Thermocouple Copper Wires Ice Bath Copper wire to thermocouple wire connection (one of two). A. Simulated Reference Junction (Front Panel Inputs) H Model 7700 Switching Module + CH 1-20 Thermocouple L Copper Wires Ice Bath Copper wire to thermocouple wire connection (one of two). B.
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2750-900-01.book Page 31 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation Table 3-3 Color codes — thermocouple wires T/C Type J Positive (+) Negative (-) T/C Type Positive (+) Negative (-) U.S. British DIN Japanese French White Yellow Red Red Yellow Red Blue Blue White Black E U.S. British DIN Japanese French Purple Brown Red Red Yellow Red Blue Black White Blue K U.S.
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2750-900-01.book Page 32 Wednesday, August 3, 2011 7:56 AM 3-32 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Thermistor connections A thermistor can be connected directly to the front panel inputs or to any of the 20 input channels of the Model 7700 switching module as shown in Figure 3-9. Figure 3-9 Thermistor connections Model 2750 Input HI Thermistor Input LO A. Front Panel Inputs Model 7700 Switching Module H CH 1-20 L B.
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2750-900-01.book Page 33 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-33 4-wire RTD connections Shown in Figure 3-10 are 4-wire RTD connections to the Model 2750. For the Model 7700 switching module, paired channels are used to perform the 4-wire measurement. The two input leads of the RTD are connected to a primary channel (1 through 10), while the two sense leads are connected to its paired channel (11 through 20).
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2750-900-01.book Page 34 Wednesday, August 3, 2011 7:56 AM 3-34 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Temperature measurement configuration The Model 2750 is configured to measure temperature from the temperature measurement configuration menu. Use the following general rules to navigate through the menu structure: • Press SHIFT and then SENSOR to enter the menu structure. • Cursor position is indicated by a flashing menu item or parameter.
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2750-900-01.book Page 35 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-35 Thermistor temperature measurement configuration The steps to configure thermistor measurements are provided in Table 3-5. After pressing SHIFT and then SENSOR, the menu starts at step 1 to select measurement units. Each time you press ENTER to make a selection, the menu will automatically go to the next selection.
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2750-900-01.book Page 36 Wednesday, August 3, 2011 7:56 AM 3-36 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual The steps to configure 4-wire RTD measurements are provided in Table 3-7. After pressing SHIFT and then SENSOR, the menu starts at step 1 to select measurement units. Each time you press ENTER to make a selection, the menu will automatically go to the next selection. After pressing ENTER for the last step, the instrument will return to the normal measurement state.
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2750-900-01.book Page 37 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual 3-37 While in the normal measurement state, you can use the and keys to close channels. In general, each key press will open the presently closed channel, and then close the next higher or lower channel. NOTE 6. 7. 8. Basic DMM Operation Observe the displayed reading. To measure other switching channels, repeat steps 5 and 6. When finished, press OPEN if there is a channel closed.
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2750-900-01.book Page 38 Wednesday, August 3, 2011 7:56 AM 3-38 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Connections NOTE When using the front panel inputs, the INPUTS switch must be in the “F” (out) position. For switching modules, it must be in the “R” (in) position. Front panel input When using the front panel input terminals, connect the test leads to the INPUT HI and LO terminals as shown in Figure 3-11.
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2750-900-01.book Page 39 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-39 Frequency and period measurement procedure NOTE 1. 2. 3. 4. Make sure the INPUTS switch is in the correct position. To use front panel inputs, it must be in the “F” (out) position. For switching modules, it must be in the “R” (in) position. If a switching channel is presently closed (displayed), press OPEN to open it.
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2750-900-01.book Page 40 Wednesday, August 3, 2011 7:56 AM 3-40 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Continuity testing The Model 2750 can test continuity using the 2-wire 1kΩ range. After selecting continuity, you will be prompted to enter the threshold resistance level (1 to 1000Ω). When the measured circuit is below the set threshold level, the instrument will beep and display the resistance readings.
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2750-900-01.book Page 41 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-41 Figure 3-13 Continuity connections Model 2750 Input HI Resistance Under Test Input LO A. Front Panel Connections Model 7700 Switching Module H CH 1-20 Resistance Under Test L B. Model 7700 Connections Note: Source current flows from input high to input low. Continuity testing procedure NOTE 1. 2. 3. 4. 5.
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2750-900-01.book Page 42 Wednesday, August 3, 2011 7:56 AM 3-42 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Remote programming for basic measurements Basic measurement commands NOTE When measurements are performed, the readings are fed to other enabled processing operations. Appendix D explains “Data flow (remote operation)” and the commands used to return the various processed readings. Commands to perform basic measurements are listed in Table 3-8.
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2750-900-01.book Page 45 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-45 Reference a. FUNCtion [, ] Note that the parameters in the table are enclosed in single quotes (‘ ’). However, double quotes (“ ”) can instead be used.
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2750-900-01.book Page 46 Wednesday, August 3, 2011 7:56 AM 3-46 Basic DMM Operation e. Model 2750 Multimeter/Switch System User’s Manual TEMPerature:FRTD:RZERo [, ] TEMPerature:FRTD:ALPHa [, ] TEMPerature:FRTD:BETA [, ] TEMPerature:FRTD:DELTa [, ] These commands are used to set the parameters for the USER RTD type. Note that the RZERo command sets the “Ω at 0°C” parameter.
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2750-900-01.book Page 47 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-47 DATA:FRESh? can only be used once to return the same reading string. That is, the reading must be “fresh.” Sending this command again to retrieve the same reading string will generate error -230 (data corrupt or stale), or cause a the GPIB to time-out. In order to again use DATA:FRESh? a new (fresh) reading must be triggered.
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2750-900-01.book Page 48 Wednesday, August 3, 2011 7:56 AM 3-48 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Basic measurement programming examples Example #1 — continuous triggering The following command sequence places the Model 2750 in a continuous trigger mode to measure ACV. Whenever DATA? is sent, the last measured reading will be sent to the computer when the Model 2750 is addressed to talk. SYST:PRES FUNC 'VOLT:AC' DATA? ' Continuous measurement mode (INIT:CONT ON).
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2750-900-01.book Page 49 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-49 Example #4 – Scan configuration (Model 7700) The following commands configure scan channels 101, 102, and 121 of a Model 7700 installed in slot 1. When channel 101 is scanned, DCV will be selected. When channel 102 is scanned, Ω2 will be selected. When channel 121 is scanned, DCI will be selected.
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2750-900-01.book Page 50 Wednesday, August 3, 2011 7:56 AM 3-50 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual :READ? What it does This command performs three actions. It will reset the trigger model to the idle layer (equivalent to the :ABORt command), take the trigger model out of idle (equivalent to the :INIT command), and return a reading (equivalent to a FETCh? query).
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2750-900-01.book Page 51 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-51 [:SENSe[1]]:DATA:FRESh? What it does This query is similar to :FETCh? in that it returns the latest reading from the instrument but has the advantage of making sure that it does not return the same reading twice. Limitations Like the :FETCh? query, this command does not trigger a reading.
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2750-900-01.book Page 52 Wednesday, August 3, 2011 7:56 AM 3-52 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual Examples One-shot reading, DC volts, no trigger, fastest rate *RST :INITiate:CONTinuous OFF;:ABORt :SENSe:FUNCtion ‘VOLTage:DC’ :SENSe:VOLTage:DC:RANGe 10 // Use fixed range for fastest readings. :SENSe:VOLTage:DC:NPLC 0.01 // Use lowest NPLC setting for fastest // readings. :DISPlay:ENABle OFF // Turn off display to increase speed.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 4 Range, Digits, Rate, Bandwidth, and Filter • Range — Provides details on measurement range selection. Includes the commands for remote programming. • Digits — Provides details on selecting display resolution. Includes the commands for remote programming. • Rate and bandwidth — Provides details on integration rate and bandwidth (for AC measurements). Includes the commands for remote programming. • Filter — Provides details on filtering.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 4-2 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Range The range setting is “remembered” by each measurement function. When you select a function, the instrument will return to the last range setting for that function. Measurement ranges and maximum readings The selected range affects both accuracy of the measurement as well as the maximum level that can be measured.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-3 If the instrument displays the “OVERFLOW” message on a particular range, select a higher range until an on-range reading is displayed. Use the lowest range possible without causing an overflow to assure best accuracy and resolution. Auto ranging To enable auto range, press the AUTO key. The AUTO annunciator turns on when auto ranging is selected.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 4-4 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Remote programming — range Range commands The commands to set range are listed in Table 4-2. Additional information on these commands follow the table. NOTE Query commands and some optional command words are not included in Table 4-2. All commands for the SENSe subsystem are provided in Table 15-5.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-5 Manual ranging The range is selected by specifying the expected reading as an absolute value using the parameter for the appropriate :RANGe command. The Model 2750 will then go to the most sensitive range for that expected reading. For example, if you expect a reading of approximately 3V, let the parameter () equal 3 to select the 10V range.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 4-6 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Remote programming — digits Digits commands The commands to control display resolution (digits) are listed in Table 4-3. Additional information on these commands follow the table. NOTE Query commands are not included in Table 4-3. All commands for the SENSe subsystem are provided in Table 15-5.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-7 Setting digits Even though the parameters for the DIGits command are expressed as integers (4 to 7), you can specify resolution using a real number. For example, to select 3Hdigit resolution, let = 3.5. Internally the instrument rounds the entered parameter value to the nearest integer.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 4-8 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Rate and bandwidth Rate The RATE key sets the integration time (measurement speed) of the A/D converter, the period of time the input signal is measured (also known as aperture). The integration time affects the amount of reading noise, as well as the ultimate reading rate of the instrument.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-9 The front panel RATE settings for all but the AC functions are explained as follow: • FAST sets integration time to 0.1 PLC. Use FAST if speed is of primary importance (at the expense of increased reading noise and fewer usable digits). MEDium sets integration time to 1 PLC.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 4-10 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Setting measurement speed — The RATE key is used to set measurement speed from the front panel. Simply press RATE until the desired speed annunciator (FAST, MED, or SLOW) turns on. NOTE The Model 2750 uses internal references to calculate an accurate and stable reading.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-11 Remote programming — rate and bandwidth Rate and bandwidth commands The commands to set the integration rate and bandwidth are listed in Table 4-5. Additional information on these commands follows the table. NOTE Query commands are not included in Table 4-5. All commands for the SENSe subsystem are provided in Table 15-5.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 4-12 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Table 4-5 (continued) Rate and bandwidth commands Commands 1, 7 Bandwidth commands [SENSe[1]] :VOLTage:AC:DETector:BANDwidth [, ] :CURRent:AC:DETector:BANDwidth [, ] Description Default Optional root command. Set AC bandwidth for ACV in Hertz; = 30 3 to 3e5.6 Set AC bandwidth for ACI in Hertz; 30 = 3to 3e5.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-13 To set bandwidth, simply specify (approximately) the frequency of the input signal.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 4-14 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Filter The digital filter is used to stabilize noisy measurements. The displayed, stored, or transmitted reading is a windowed-average of a number of reading conversions (from 1 to 100). The filter setup is “remembered” and can be unique for each measurement function (DCV, ACV, DCI, ACI, Ω2, Ω4, and TEMP).
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-15 For voltage, current, and resistance, the filter window is expressed as a percent of range. For example, on the 10V range, a 10% window means that the filter window is ±1V. For temperature, the filter window is expressed as a percent of the maximum temperature reading. The maximum temperature depends on which thermocouple is being used.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 4-16 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Figure 4-2 Moving and repeating filters Conversion Conversion #10 #9 #8 #7 #6 #5 #4 #3 #2 #1 Conversion Average Reading #1 Conversion #11 #10 #9 #8 #7 #6 #5 #4 #3 #2 Conversion Average Reading #2 Conversion #12 #11 #10 #9 #8 #7 #6 #5 #4 #3 Average Reading #3 #30 #29 #28 #27 #26 #25 #24 #23 #22 #21 Average Reading #3 A.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual NOTE Range, Digits, Rate, Bandwidth, and Filter 4-17 Bit 8 of the Operation Event Status Register sets when the filter window has properly settled (or the filter is disabled). See Section 11, “Status Structure,” for details. Filter control and configuration The FILTER key toggles the state of the Filter. When the Filter is enabled, the FILT annunciator is on.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 4-18 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Figure 4-3 Filter configuration flow chart SHIFT TYPE 0.01% WINDOW 0.1% 1% NONE RDGS 001 to 100 TYPE REPEAT MOVNG AV Scanning The moving filter cannot be used when scanning. A scan channel cannot be configured to use the moving filter. Also, the filter window is not used when scanning.
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Range, Digits, Rate, Bandwidth, and Filter 4-19 Remote programming — filter Filter commands The filter commands are listed in Table 4-6. Additional information on these commands follow the table. NOTE Query commands are not included in Table 4-6. All commands for the SENSe subsystem are provided in Table 15-5.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 4-20 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Table 4-6 (continued) Filter commands Commands1, 4 Description5 DCI filter commands [SENSe[1]] Optional root command. :CURRent[:DC]:AVERage:TCONtrol Select filter type; = MOVing or REPeat. :CURRent[:DC]:AVERage:WINDow Set filter window in %; = 0 to 10. :CURRent[:DC]:AVERage:COUNt Specify filter count; = 1 to 100.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 4-22 Range, Digits, Rate, Bandwidth, and Filter Model 2750 Multimeter/Switch System User’s Manual Filter programming examples Example #1 — The following command sequence configures filtering for the DCI function: CURR:TCON MOV CURR:AVER:WIND 0.01 CURR:AVER:COUN 10 CURR:AVER ON ' ' ' ' Select the moving filter. Set filter window to 0.01%. Set to filter 10 readings. Enable filter.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 5 Relative, Math, Ratio, Channel Average, and dB • Relative — Explains how to null an offset or establish a baseline value. Includes the commands for remote programming. • Math — Covers the three basic math operations: mX+b, percent, and reciprocal (1/X). Includes the commands for remote programming. • Ratio and channel average — Explains how to use these calculations to display the ratio or average of two switching channels.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 5-2 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Relative The rel (relative) function can be used to null offsets or subtract a baseline reading from present and future readings. When rel is enabled, the instrument uses the present reading as a relative value. Subsequent readings will be the difference between the actual input value and the rel value. You can define a rel value for each function.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-3 Pressing REL a second time disables rel. You can input a rel value manually using the mX+b function. Set M for 1 and B for any value you want. The mX+b function is covered in this section (see “Math,” page 5-8). Scanning When a simple scan is configured, the present rel setting will apply to all channels in the scan.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 5-4 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Remote programming — rel Rel commands The rel commands to set range are listed in Table 5-1. Additional information on these commands follow the table. NOTE Query commands are not included in Table 5-1. All commands for the SENSe subsystem are provided in Table 15-5.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 5-6 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Table 5-1 (continued) Rel commands Commands1 Rel commands for PERIOD [SENSe[1]] :PERiod:REFerence [, ] :PERiod:REFerence:STATe [, ] :PERiod:REFerence:ACQuire [, ] Description Optional root command. Specify rel value; = 0 to 1 (sec). Enable/disable rel; = ON or OFF. Use input signal as rel value.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-7 value. When rel is set using :ACQuire, the :REFerence? query command returns the acquired rel value. Rel programming examples Example #1 — The following command sequence zeroes the display for DCV. FUNC 'VOLT' VOLT:REF:ACQ VOLT:REF:STAT ON ' Select DCV. ' Use input level as rel value for DCV. ' Enable rel.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 5-8 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Math The Model 2750 has three built-in math calculations that are accessed from the MATH menu: mX+b, percent, and reciprocal (1/X). Figure 5-1 shows the MATH menu tree. Note that the settings shown in the menu tree are the factory defaults. NOTE The various instrument operations, including Math, are performed on the input signal in a sequential manner.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-9 mX+b This math operation lets you manipulate normal display readings (X) mathematically according to the following calculation. Y = mX + b where: X is the normal display reading. m and b are the user-entered constants for scale factor and offset. Y is the displayed result.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 5-10 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual mX+b rel The mX+b function can be used to manually establish a rel value. To do this, set the scale factor (M) to 1 and set the offset (b) to the rel value. Each subsequent reading will be the difference between the actual input and the rel value (offset). Percent This math function determines percent deviation from a specified reference value.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-11 Reciprocal (1/X) The reciprocal of a reading is displayed when the reciprocal (1/X) math function is enabled: Reciprocal = 1/X where: X is the normal input reading The displayed units designator for reciprocal readings is “R.” This units designator cannot be changed. Example — Assume the normal displayed reading is 002.5000Ω.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 5-12 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Basic operation NOTE 1. 2. 3. NOTE 4. If using switching module inputs, make sure the front panel INPUTS switch is set to the REAR position (in). If using the front panel inputs, the switch must be in the FRONT position (out). Configure and enable the mX+b, percent, or reciprocal (1/X) math function as previously explained.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-13 Remote programming — math Math commands NOTE When measurements are performed, the readings are fed to other enabled processing operations, including Math. Appendix D explains “Data flow (remote operation)” and the commands used to return Math results. The commands to perform math calculations are listed in Table 5-2.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 5-14 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Setting mX+b units The parameter for CALCulate:KMATh:MUNits must be one character enclosed in single or double quotes. It can be any letter of the alphabet, the degrees symbol (°) or the ohms symbol (Ω).
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-15 Math programming examples Example #1 — The following command sequence performs the mX+b calculation for channels 101 and 102 of the Model 7700. Keep in mind that after CALC:DATA? is sent, the Model 2750 has to be addressed to talk to send the math result to the computer.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 5-16 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Ratio and channel average With a switching module installed in the Model 2750, the ratio or average of two channels can be calculated and displayed. The ratio calculation can be done on the DCV function, and the channel average calculation can be done on the DCV and TEMP (thermocouples only) functions.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-17 Basic operation NOTE 1. 2. 3. 4. 5. NOTE Make sure the INPUTS switch is set to the REAR position (in). Select and configure (range, filter, rel, etc.) a valid measurement function. For ratio, the only valid function is DCV. For channel average, the only valid functions are DCV and TEMP (TCs only).
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 5-18 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Scanning Ratio and channel average can be used in an advanced scan. The 2-channel scan for the calculation is performed for every primary channel that is scanned. For example, assume the Model 7700 is installed in slot 1 and is configured to perform the ratio calculation for 10 channels.
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-19 Remote programming — ratio and channel average Ratio and channel average commands The ratio and channel average are listed in Table 5-3. Details on these commands follow the table. NOTE Queries are not included in Table 5-3. All the math commands are provided in Table 15-1.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 5-20 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Enabling/disabling ratio or channel average As with front panel operation, enabling ratio disables channel average and conversely, enabling channel average disables ratio. Ratio and channel average delay :RATio:DELay or :CAVerage:DELay sets the delay between the two channel measurements for the enabled calculation.
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2750-900-01.book Page 21 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Rel, Math, Ratio, Channel Average, dB 5-21 dB Expressing DC or AC voltage in dB makes it possible to compress a large range of measurements into a much smaller scope. The relationship between dB and voltage is defined by the following equation: V IN dB = 20log ------------V REF where: VIN is the DC or AC input signal. VREF is the specified voltage reference level.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 5-22 Rel, Math, Ratio, Channel Average, dB Model 2750 Multimeter/Switch System User’s Manual Table 5-4 dB commands Commands* DCV dB commands UNITs:VOLTage[:DC] UNITs:VOLTage[:DC]:DB:REFerence ACV dB commands UNITs:VOLTage:AC UNITs:VOLTage:AC:DB:REFerence Description Def Select DCV measurements; = V or DB. Set reference in volts; = 1e-7 to 1000. V Select ACV measurements; = V or DB.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 6 Buffer • Buffer overview — Summarizes basic buffer (data store) capabilities. • Front panel buffer — Explains how to store and recall readings, and discusses the various statistics available on buffer data including minimum and maximum values, average (mean), standard deviation, and peak-to-peak values. • Remote programming buffer — Summarizes the commands to control the data store and provides a programming example.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 6-2 Buffer Model 2750 Multimeter/Switch System User’s Manual Buffer overview The Model 2750 has a data store (buffer) to store from 2 to 110,000 readings. The instrument stores the readings that are displayed during the storage process. Each timestamped reading includes the buffer location number and a timestamp. The data store also provides statistical data on the measured readings stored in the buffer.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual NOTE Buffer 6-3 If the buffer is empty when the Model 2750 is turned off, buffer auto clear will enable when it is turned back on. If the buffer is not empty, the instrument will power up to the last auto clear setting. Keep in mind that if the instrument powers up with buffer auto clear off, buffer size is fixed at 110000. You will have to enable auto clear to change the buffer size.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 6-4 Buffer Model 2750 Multimeter/Switch System User’s Manual NOTE With auto clear disabled and the relative timestamp selected, every stored reading is referenced to the first reading (#0), even if the buffer is stopped and started again. For example, assume you stored 10 readings in the buffer, and one hour later, you store 10 more readings. The timestamps for all 20 readings are referenced to the first reading.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Buffer 6-5 Selecting timestamp Perform the following steps to select either the real-time clock timestamp or the relative timestamp: NOTE 1. 2. 3. 4. Changing the timestamp will clear the buffer if a storage is in process. The message “BUF CLEARED” will be displayed to indicate the buffer readings were lost. If no storage is in process, changing the timestamp will not clear the buffer.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 6-6 Buffer Model 2750 Multimeter/Switch System User’s Manual Recalling readings Readings stored in the buffer are displayed by pressing the RECALL key. The readings are positioned at the left side of the display, while the buffer location number (reading number) and timestamps are positioned at the right side. Perform the following steps to view stored readings and buffer statistics: 1. 2. Press RECALL.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Buffer 6-7 Figure 6-2 Recalling buffer data — real-time clock timestamp RANGE RANGE RDG RDG RDG RDG RDG RDG RDG RDG RDG RDG STD Average Peak-to-Peak Min Max NO. NO. NO. NO. NO. NO. NO. NO. NO. NO.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 6-8 Buffer Model 2750 Multimeter/Switch System User’s Manual Standard deviation This mode displays the standard deviation of buffered readings. The following equation is used to calculate standard deviation: 2 n ⎛ ⎛ n ⎞ ⎞ 1 ∑ Xi – ⎜⎜ --n- ⎜⎜ ∑ Xi⎟⎟ ⎟⎟ ⎝ ⎝i = 1 ⎠ ⎠ i = n–1 --------------------------------------------------------------n–1 2 y = where: y is the standard deviation. Xi is a stored reading. n is the number of stored readings.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual NOTE Buffer 6-9 Optional command words and most queries are not included in Table 6-1. The unabridged tables for all SCPI commands are provided in Section 15.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 6-10 Buffer Model 2750 Multimeter/Switch System User’s Manual a. SYSTem:TIME Set clock time Use to set the clock time in the 24-hour format (hr/min/sec). Seconds can be set to 0.01 sec resolution. Examples: SYST:TIME 13, 23, 36 SYST:TIME 3, 25, 28.5 ' Set time to 1:23:36 PM. ' Set time to 3:25:28.5 AM. The SYSTem:TIME? command can be used to read the time.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual f. TRACe:POINts 2 to 110000 Buffer 6-11 Set buffer size With buffer auto-clear enabled, you can set the buffer to store from 2 to 110,000 readings. A buffer size of zero or one is not valid (error -222). With buffer auto-clear disabled, you cannot use this command to set buffer size (error -221) because it is fixed at 110,000. NOTE g.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 6-12 Buffer Model 2750 Multimeter/Switch System User’s Manual j. TRACe:DATA:SELected? , TRACe:NEXT? Specify readings to return Query location of last buffer reading Use the TRACe:DATA:SELected? command to specify which stored readings to return. The parameter specifies the first stored reading to return. Note that the first stored reading in the buffer is #0.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual l. FORMat:ELEMents Buffer 6-13 Select elements for TRACe:DATA? = READing, CHANnel, UNITs, RNUMber, TSTamp The data returned by TRACe:DATA? can include from one to all five data elements shown in the above item list. For example, if you want the units and reading number included with the reading, you would send this command: FORMat:ELEMents READing, UNITs, RNUMber.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 6-14 Buffer Model 2750 Multimeter/Switch System User’s Manual m.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 7 Scanning • Scanning fundamentals — Explains channel assignments (slot/channel programming format), the difference between sequential and non-sequential scans, and the basic scan process. Block diagrams (known as trigger models) are provided to help explain the STEP and SCAN operations. • Scan configuration — Provides the step-by-step procedures to configure a simple scan or an advanced scan.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 7-2 Scanning Model 2750 Multimeter/Switch System User’s Manual Scanning fundamentals The Model 2750 can scan the channels of up to five installed Keithley switching modules. Each scan channel can have its own unique setup.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-3 Channel assignments A switching module has a certain number of channels. For example, the Model 7700 switching module has 22 channels (1 through 22). When you encounter a 1 or 2-digit channel number in this manual, the switching module channel is the point of discussion. A switching module can be installed in one of five slots of the mainframe.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 7-4 Scanning Model 2750 Multimeter/Switch System User’s Manual closed channels, (2) close the paired channels, and then (3) perform the 4-wire measurement. The last scanned channel pair opens. NOTE For the Model 7700 switching module, primary channels 1 through 10 are paired to channels 11 through 20. Channel 1 is paired to channel 11, channel 2 is paired to channel 12, channel 3 is paired to channel 13, and so on.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-7 STEP operation overview — When the STEP key is pressed, the Model 2750 leaves the idle state, closes the first channel, and waits for the programmed trigger event. After the trigger is detected, the instrument may be subjected to one or more delays before performing the measurement.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 7-8 Scanning Model 2750 Multimeter/Switch System User’s Manual Immediate control source With immediate triggering, event detection is immediate allowing channels to be scanned. Timer control source With the timer source enabled (selected), event detection is immediately satisfied. On the initial pass through the loop, the Timer Bypass is enabled allowing operation to bypass the Timer and continue to the Delay block.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-9 Delay (Auto or Manual) — The user can select either auto delay or manual delay. With auto delay selected, the instrument automatically selects a delay period that will provide sufficient settling for function and autorange changes, and multi-phase measurements. The auto delay period cannot be adjusted by the user. It is a fixed delay for the selected function and range (Table 8-1).
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 7-10 Scanning Model 2750 Multimeter/Switch System User’s Manual SCAN operation — When a scan is started, one or more complete scans will be performed. The number of channels in the scan list determines the number of channels for each scan. The reading count determines the number of scans to perform and is best explained by an example. Assume there are 10 channels in the scan list.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-11 Scan configuration A scan is configured from the scan configuration menu which is accessed by pressing SHIFT and then CONFIG. Figure 7-3 shows the basic flowchart to configure a scan. After entering the menu structure you can configure a simple scan, an advanced scan, or reset the configuration to the default setup for a simple scan.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 7-12 Scanning Model 2750 Multimeter/Switch System User’s Manual There are two scan configurations: simple and advanced. When you configure the simple scan, the instrument uses the present instrument setup for each channel in the scan. For the advanced scan, each channel can have its own unique setup. As explained in “Trigger models,” page 7-4, there is a user-set delay (auto or manual) that is in effect for both the simple and advanced scan.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-13 Scan reset From the scan configuration menu, you can reset the scan configuration to the default setup for a simple scan. For the Model 7700 switching module, channels 21 and 22 are turned off (not used), and channels 1 through 20 are configured as follows: Function - DCV Range - Auto Rate - Slow All other multimeter features and functions are disabled.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 7-14 Scanning Model 2750 Multimeter/Switch System User’s Manual 7. 8. If you enabled the timer, set the timer interval using the hour/minute/second format. The timer can be set from 0.001 sec (00H:00M:00.001S) to 99 hrs, 99 min, 99.999 sec (99H:99M:99.999S). Note that pressing the AUTO key sets the timer to 0.001 sec. With the desired interval displayed, press ENTER.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-15 Advanced scan setup notes 1. 2. 3. 4. 5. NOTE The CHAN annunciator is on while in the scan setup menu. For some channel-specific setups, you have to configure them from a menu. For example, to set up and enable mX+B, you have to use MATH menu.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 7-16 Scanning Model 2750 Multimeter/Switch System User’s Manual Advanced scan setup procedure Step 1: Select the advanced scan configuration menu 1. 2. Press SHIFT and then CONFIG to access the scan setup menu. Press the Δ or ∇ key to display INT: ADVANCED and press ENTER. Step 2: Edit scan channels 1. Use the or key to select channel 101: SETUP V:101 (factory default) NOTE 2. NOTE 3. 4. 5.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-17 Step 3: Enable immediate scan The present state of immediate scan (IMM SCAN) is displayed; Y (yes, which is the factory and *RST default) or N (no). With immediate scan enabled, the scan will start when you press the STEP or SCAN key. Use the Δ or ∇ key to display IMM SCAN: Y, and press ENTER.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 7-18 Scanning Model 2750 Multimeter/Switch System User’s Manual NOTE 4. Pressing the AUTO key sets the manual delay to 0.001 sec. With the desired manual delay displayed, press ENTER. For remote programming, the TRIGer:DELay and TRIGger:DELay:AUTO commands are used to set the delay. See Table 7-1 for details. NOTE The delay for ratio and channel average can only be set using remote programming (Table 5-3).
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-19 Method 1: 1. 2. Use the CLOSE key or the and keys to close the channel that you want to be the monitor. Press SHIFT and then MONITOR (MON annunciator turns on). Method 2: 1. 2. 3. If a channel is closed, press OPEN to open it. Press SHIFT and then MONITOR. Use the , , Δ , and ∇ keys to display the monitor channel (i.e., MONITOR 101), and press ENTER.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 7-20 Scanning Model 2750 Multimeter/Switch System User’s Manual NOTES Auto channel configuration cannot be enabled if there is a non-scan channel presently closed. For example, assume the scan list consists of channels 105 through 110, and channel 101 (a non-scan channel) is presently closed. When you attempt to enable auto channel configuration from the front panel, the message “NOT IN SCAN” is briefly displayed.
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2750-900-01.book Page 21 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-21 resumed. Error +517 occurs (cannot resume scan) to indicate that the scan has been disabled. The instrument assumes the normal power-on setup. The Model 7706 does not support auto scan. Trying to enable auto scan with a Model 7706 card installed will cause error -221 (settings conflict). Scan operation A basic scan is controlled solely by the STEP and SCAN keys.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 7-22 Scanning Model 2750 Multimeter/Switch System User’s Manual NOTE Channels for an advanced scan can be configured using different mX+B units (i.e., ° and ¾), temperature sensors (I.e., 4-wire RTD and thermistor), and measurement type (i.e., OCOMP ohms and DCV). However, when readings are recalled from the buffer, the display may not indicate the correct mX+B units symbol or annunciator for each channel.
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2750-900-01.book Page 23 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-23 Manual/external trigger scan The only difference between a manual/external trigger scan and the basic scan is control. The basic scan runs as soon as the STEP or SCAN key is pressed. The manual/external trigger scan is controlled by the front panel TRIG key or by triggers received from another instrument. NOTE 1. 2. 3. 4. 5.
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2750-900-01.book Page 24 Wednesday, August 3, 2011 7:56 AM 7-24 Scanning Model 2750 Multimeter/Switch System User’s Manual Monitor scan (analog trigger) A channel can be assigned as a monitor channel. When the monitor channel detects that a reading limit has been reached, the scan will be triggered to start. There are four reading limits that can be used to trigger the start of the scan: low limit 1 (LLIM1), high limit 1 (HLIM1), low limit 2 (LLIM2), and high limit 2 (HLIM2).
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2750-900-01.book Page 25 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-25 Press the Δ or ∇ key to enable or disable low limit 1 (LLIM1 SCAN:N/Y), and press ENTER. b. Press the Δ or ∇ key to enable or disable high limit 1 (HLIM1 SCAN:N/Y), and press ENTER. c. Press the Δ or ∇ key to enable or disable low limit 2 (LLIM2 SCAN:N/Y), and press ENTER. d. Press the Δ or ∇ key to enable or disable high limit 2 (HLIM2 SCAN:N/Y), and press ENTER.
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2750-900-01.book Page 26 Wednesday, August 3, 2011 7:56 AM 7-26 Scanning Model 2750 Multimeter/Switch System User’s Manual Remote programming — scanning NOTE Scanning examples (remote programming and front panel operation) are provided at the end of this section. Trigger model The trigger model for bus operation is shown in Figure 7-2.
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2750-900-01.book Page 27 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-27 Channel setup The parameter is used to set up scan channels. For example, the following examples show how to set up scan channel 101: FUNC 'VOLT', (@101) VOLT:RANG 10, (@101) VOLT:DIG 4.5, (@101) VOLT:NPLC 3, (@101) NOTE ' ' ' ' Set Set Set Set 101 101 101 101 for DCV. for 10V range. for 4H digit resolution. rate for 3 PLC.
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2750-900-01.book Page 28 Wednesday, August 3, 2011 7:56 AM 7-28 Scanning Model 2750 Multimeter/Switch System User’s Manual Table 7-1 Scanning commands Commands Description Scan commands ROUTe:SCAN ROUTe:SCAN? ROUTe:SCAN:TSOurce Specify list of channels to be scanned. Returns list of channels to be scanned. Select trigger(s) to start scan; = IMMediate, or HLIMit1, LLIMit1, HLIMit2, LLIMit2. ROUTe:SCAN:NVOLatile Enable or disable auto scan; = ON or OFF.
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2750-900-01.book Page 29 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-29 Table 7-1 (continued) Scanning commands Commands Trigger commands TRIGger:SOURce Description TRIGger:TIMer TRIGger:COUNt TRIGger:DELay TRIGger:DELay:AUTO SAMPle:COUNt SAMPle:COUNt? INITiate:CONTinuous INITiate READ? Select control source; = IMMediate, TIMer, MANual, BUS, or EXTernal. Set timer interval in sec; = 0.001 to 999999.999.
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2750-900-01.book Page 30 Wednesday, August 3, 2011 7:56 AM 7-30 Scanning Model 2750 Multimeter/Switch System User’s Manual Reference a. ROUTe:SCAN — Channels will be scanned in the order that they are listed.
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2750-900-01.book Page 31 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-31 For the 4-wire resistance function, channels 101through 110 will be paired to channels 111 through 120. ROUT:SCAN? returns the following scan list: (@101:110) Now assume the scan is returned to DCV function as follows: SENS:FUNC ‘VOLT’,(@101:120) The above command sets channels 101 through 120 for DCV. However, it will NOT affect the scan list.
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2750-900-01.book Page 32 Wednesday, August 3, 2011 7:56 AM 7-32 Scanning Model 2750 Multimeter/Switch System User’s Manual e. f. SAMPle:COUNt and TRIGger:COUNt — Sample count specifies the number of readings to scan and store in the buffer, while the trigger count specifies the number of scans to perform. If the sample count is greater than the number of channels in the scan list (scan list length), operation wraps around to the beginning of the scan list and continues.
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2750-900-01.book Page 33 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning 7-33 Scanning examples The following scanning examples assume that the Model 7700 switching module is installed in slot 1 of the mainframe. Tables are used for the procedure steps to configure and run scan examples. The left side of the table provides the front panel procedure, while the right side shows the equivalent remote programming commands.
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2750-900-01.book Page 34 Wednesday, August 3, 2011 7:56 AM 7-34 Scanning Model 2750 Multimeter/Switch System User’s Manual Operation A simplified model of external trigger scan operation is shown in Figure 7-4, while the procedure steps and programming commands are listed in Table 7-2. As shown in the operation model, when the scan is enabled, channel 101 closes and the Model 2750 waits for an external trigger. When the trigger is received, channels 101 and 102 are measured.
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2750-900-01.book Page 35 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Scanning Table 7-2 External trigger scan example Front panel operation 1 Restore defaults: Restore defaults (SHIFT SETUP > RESTORE: FACT). 2 For front panel operation, proceed to step 3. For remote programming, clear buffer and disable buffer auto clear: 3 a b c d e f Configure advanced scan: (SHIFT CONFIG > ADVANCED): Channel 101: Select TEMP function.
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2750-900-01.book Page 36 Wednesday, August 3, 2011 7:56 AM 7-36 Scanning Model 2750 Multimeter/Switch System User’s Manual Monitor scan For this example, channel 101 of the Model 7700 is used to monitor temperature. When the temperature reading reaches 30°C, it will start the scan. For this 4-channel scan, channel 101 measures temperature, while channels 102, 103, and 104 measure DCV. This example uses the Channel Average feature to measure temperature.
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2750-900-01.book Page 38 Wednesday, August 3, 2011 7:56 AM 7-38 Scanning Model 2750 Multimeter/Switch System User’s Manual Table 7-3 Monitor scan example Front panel operation Remote programming 1 Restore defaults (SHIFT SETUP > RESTORE: FACT). SYST:PRES 2 For front panel operation, proceed to step 3. For remote programming, clear the buffer: TRAC:CLE 3 a b c d e f g 4 Configure advanced scan: SHIFT CONFIG > ADVANCED: Channel 101: Select TEMP function.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 8 Triggering • Trigger model — Explains the various components of the front panel trigger model, which controls the triggering operations of the instrument. • External triggering — Explains external triggering which allows the Model 2750 to trigger and be triggered by other instruments. • Remote programming — triggering — Covers remote operation for triggering including the GPIB trigger model and the commands.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 8-2 Triggering Model 2750 Multimeter/Switch System User’s Manual Trigger model The flow chart in Figure 8-1 summarizes triggering as viewed from the front panel. It is called a trigger model because it is modeled after the SCPI commands used to control triggering. NOTE For scanning, the trigger model has additional control blocks, such as a Timer. These are described in Section 7 (Figure 7-1 and Figure 7-2).
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-3 Control source and event detection The control source holds up operation until the programmed event occurs and is detected. The control sources are described as follows: • • Immediate — With this control source, event detection is immediately satisfied allowing operation to continue.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-5 Device action The primary device action is a measurement.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 8-6 Triggering Model 2750 Multimeter/Switch System User’s Manual External triggering The EX TRIG key selects triggering from three external sources: trigger link, digital I/O, and the TRIG key. When EX TRIG is pressed, the TRIG annunciator lights and dashes are displayed to indicate the instrument is waiting for an external trigger. From the front panel, press the TRIG key to trigger a single reading.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-7 External trigger The EXT TRIG input requires a falling-edge, TTL-compatible pulse with the specifications shown in Figure 8-4. In general, external triggers can be used to control measure operations. For the Model 2750 to respond to external triggers, the trigger model must be configured for it.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 8-8 Triggering Model 2750 Multimeter/Switch System User’s Manual External triggering example For a test system that requires a large number of switching channels, the Model 2750 can be used with external scanners such as the Keithley Models 7001 and 7002. For example, 10 Model 7011s installed in the Model 7002 can provide up to 400 2-pole channels, as shown in Figure 8-6.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-9 The Trigger Link connections for this test system are shown in Figure 8-7. Trigger Link of the Model 2750 is connected to Trigger Link (either IN or OUT) of the Model 7002. Note that with the default trigger settings on the Model 7002, line #1 is an input and line #2 is an output. This complements the trigger lines on the Model 2750.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 8-10 Triggering Model 2750 Multimeter/Switch System User’s Manual 1. 2. Press EX TRIG to place the Model 2750 in the external trigger mode. Press STEP on the Model 7002 to take it out of idle and start the scan. The scanner’s output pulse triggers the Model 2750 to take a reading, store it, and send a trigger pulse. The following explanation on operation is referenced to the operation model shown in Figure 8-8.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual C. D. E & F. Triggering 8-11 For the first pass through the model, the scanner does not wait at point B for a trigger. Instead, it closes the first channel. After the relay settles, the Model 7002 outputs a Channel Ready pulse. Since the instrument is programmed to scan 400 channels, operation loops back up to point B, where it waits for an input trigger.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 8-12 Triggering Model 2750 Multimeter/Switch System User’s Manual Figure 8-9 DIN to BNC trigger cable Model 220 Current Source 8503 DIN to BNC Trigger Cable External Trigger INPUT OUTPUT Trigger Link ! DIGITAL I/O TRIG. LINK RS-232 KEITHLEY SLOT COVER IEEE-488 SLT 1 MADE IN U.S.A.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-13 What happens next depends on the state of initiation. If continuous initiation is already enabled, the instrument will leave the idle state. SYSTem:PRESet enables continuous initiation. Therefore, operation will immediately leave the idle state when it is sent. The *RCL command will do the same if INITiation:CONTinuous ON is a user saved default.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-15 Trigger model operation Once the instrument is taken out of idle, operation proceeds through the trigger model down to the device action. In general, the device action includes a measurement and, when scanning, closes the next channel. Control Source — As shown in Figure 8-10, a control source is used to hold up operation until the programmed event occurs.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 8-16 Triggering Model 2750 Multimeter/Switch System User’s Manual The trigger model can be configured to output a trigger after the completion of a series of measurements, or after every measurement. For example, with the sample counter set to 10 and the trigger counter set to one, a trigger will be sent after the 10 measurements are performed.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Triggering 8-17 Reference a. b. c. d. ABORt With continuous initiation disabled, the 2750 goes into the idle state. With continuous initiation enabled, operation continues at the top of the trigger model. INITiate Whenever the instrument is operating within the trigger model, sending this command causes an error and will be ignored.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 9 Limits and Digital I/O • Limits — Explains how to perform limit tests on measured readings. • Digital I/O — Covers the digital I/O port. Explains how the five digital outputs respond to the results of limit tests. • Remote programming — limits and digital output — Summarizes the commands to perform limit tests and control the digital I/O port.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 9-2 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Limits NOTE Limits cannot be used with the CONT function. When using limits, you can set and control the values that determine the HIGH/IN/LOW status of subsequent measurements. The limit test is performed on the result of an enabled Rel, Math, Ratio, or Channel Average operation.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-3 Overflow readings — A reading that exceeds the present measurement range causes the “OVRFLW” message to be displayed. The “IN,” “1,” and “2” messages are not displayed while in the overflow condition. The HIGH annunciator will turn on to indicate an out of limits reading. The LOW annunciator is not used for an overflow reading.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 9-4 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Scanning When a simple scan is configured, the present limit values and state will apply to all channels in the scan. When an advanced scan is configured, each channel can have its own unique limits configuration. Details to configure and run a scan are provided in Section 7. For remote programming, the parameter is used to configure channels for a scan.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-5 Digital I/O Model 2750’s Digital I/O port is accessed at a male DB-9 connector located on the rear panel. The connector location and pin designations are shown in Figure 9-2. Figure 9-2 Digital I/O port Model 2750 ! DIGITAL I/O TRIG. LINK RS-232 KEITHLEY SLOT COVER IEEE-488 SLT 1 MADE IN U.S.A.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 9-6 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Digital outputs The digital I/O port has five digital outputs. Each digital output can be used as a sink to control devices (e.g., relays), or as a source to provide input to external logic (TTL or CMOS) circuitry. The simplified schematic for the digital outputs are shown in Figure 9-3. Note that this illustration shows the schematic for one digital output.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-7 Logic sense The selected logic sense (active high or active low) determines if an output is pulled high or low when the limit is reached. If logic sense is set high, the output line will be pulled high when the reading reaches or exceeds the limit. If logic sense is set low, the output line will be pulled low to 0V when the reading reaches or exceeds the limit.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 9-8 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Sink mode — controlling external devices Each output can be operated from an external supply (voltage range from +5V to +33V applied through the external device being driven). The high current sink capacity of the output driver allows direct control of relays, solenoids, and lamps (no additional circuitry needed).
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-9 Figure 9-4 Controlling externally powered relays Model 2750 Pin 7 - Diode Clamp 33V +5V Digital Output #1 Flyback Diode 4.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 9-10 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Source mode — logic control The digital outputs can be used as logic inputs to active TTL, low-power TTL, or CMOS inputs. For this mode of operation, the output lines can source up to 200µA. CAUTION Each output line can source up to 200µA. Exceeding 200µA may cause damage to Model 2750 that is not covered by the warranty.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-11 Setting digital output The OUTPUT menu (shown in Table 9-1) is used to control and configure digital outputs. Menu items for the digital output include: • • NOTE • • DOUTPUT — Use to enable (ON) or disable (OFF) the digital outputs. PULSE — Use to enable (YES) or disable (NO) the pulse option for the digital outputs. The factory default pulse time is 2ms maximum.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 9-12 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Perform the following steps to enable and configure digital outputs: 1. 2. 3. 4. 5. 6. 7. 8. Press SHIFT and then OUTPUT. If the digital output is already on (DOUTPUT: ON), proceed to step 3. Otherwise, press to move the cursor to the right, press Δ or ∇ key to display “ON,” and press ENTER.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-13 Remote programing — limits and digital output Limits and digital output commands The limits and digital output commands are provided in Table 9-2.
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0-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 9-14 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Table 9-2 (continued) Limits and digital I/O commands Commands* Description Digital output commands CALCulate3:OUTPut:LSENse CALCulate3:OUTPut:[STATe] Set logic sense; = AHIGh or ALOW. Enable/disable digital outputs; = ON or OFF. CALCulate3:OUTPut:PULSe:TIMe Set output pulse time in secs; = 0.001 to 99999.999.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual b. c. Limits and Digital I/O 9-15 CALCulate3:LIMit1:FAIL? CALCulate3:LIMit2:FAIL? These commands are used to query the results of Limit 1 and Limit 2: 0 = Passing (reading within the high and low limits) 1 = Failing (reading has reached or exceeded the high or low limit) The “1” response message does not tell you which limit (high or low) has been reached.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 9-16 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Application — sorting resistors For this application, the idea is to sort a batch of 100Ω resistors into three bins. Bin 1 is for resistors that are within 1% of the nominal value. Bin 2 is for resistors that exceed 1% tolerance, but are within 5%. Bin 3 is for resistors that exceed 5% tolerance.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Limits and Digital I/O 9-17 Limit 1 will be used to test for the 1% tolerance and Limit 2 will be used to test for the 5% tolerance. The resistance values for the 1% and 5% tolerances are calculated as follows: R1% = 100Ω × 1% = 100Ω × 0.01 = 1Ω R5% = 100Ω × 5% = 100Ω × 0.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 9-18 Limits and Digital I/O Model 2750 Multimeter/Switch System User’s Manual Remote Operation — For remote operation, make sure both Limit 1 and Limit 2 are enabled. The following table evaluates the three possible pass/fail combinations for this example.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 10 Remote Operations • Operation enhancements — Summarizes some of the more important operations that can only be performed using remote operation. • GPIB setup — Covers GPIB bus standards, selecting the GPIB, primary address selection, and bus connections. • General bus commands — Describes general bus commands used for fundamental GPIB control.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 10-2 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Operation enhancements There are some operations you can do over the IEEE-488 bus and RS-232 interface that you cannot do from the front panel. The more important ones are summarized below. Pseudocards Using remote operation, you can assign a pseudocard to an empty switching module slot.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-3 Separate function setups A few settings from the front panel are global. That is, the setting on one function also applies to the other functions. For example, if you set DCV for 3Hdigits, all the other functions will also be set to 3Hdigits. Using remote programming, each function can have its own unique setup.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 10-4 Remote Operations Model 2750 Multimeter/Switch System User’s Manual GPIB setup The following provides information about GPIB standards, selecting the GPIB, setting the primary address, and bus connections. GPIB standards The GPIB is the IEEE-488 instrumentation data bus with hardware and programming standards originally adopted by the IEEE (Institute of Electrical and Electronic Engineers) in 1975.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-5 GPIB connections To connect the Model 2750 to the GPIB bus, use a cable equipped with standard IEEE-488 connectors as shown in Figure 10-1. Figure 10-1 IEEE-488 connector To allow many parallel connections to one instrument, stack the connectors. Two screws are located on each connector to ensure that connections remain secure.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 10-6 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Figure 10-2 shows a typical connecting scheme for a multi-unit test system. Figure 10-2 IEEE-488 connections Instrument Instrument Instrument Controller To avoid possible mechanical damage, stack no more than three connectors on any one unit. NOTE To minimize interference caused by electromagnetic radiation, use only shielded IEEE-488 cables.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-7 Figure 10-3 IEEE-488 connector location Model 2750 ! DIGITAL I/O TRIG. LINK RS-232 KEITHLEY SLOT COVER IEEE-488 SLT 1 MADE IN U.S.A. SLT 2 CAT I SLT 3 KEITHLEY SLOT COVER SLT 4 KEITHLEY SLOT COVER SLT 5 ! IEEE-488 General bus commands General commands are those commands, such as DCL, that have the same general meaning regardless of the instrument.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 10-8 Remote Operations Model 2750 Multimeter/Switch System User’s Manual REN (remote enable) The remote enable command is sent to the Model 2750 by the controller to set up the instrument for remote operation. Generally, the instrument should be placed in the remote mode before you attempt to program it over the bus. Setting REN true does not place the instrument in the remote state.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-9 DCL (device clear) Use the DCL command to clear the GPIB interface and return it to a known state. Note that the DCL command is not an addressed command, so all instruments equipped to implement DCL will do so simultaneously.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 10-10 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Front panel GPIB operation This section describes aspects of the front panel that are part of GPIB operation, including messages, status indicators, and the LOCAL key. Error and status messages See Appendix C for a list of error and status messages associated with IEEE-488 programming.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-11 SRQ You can program the instrument to generate a service request (SRQ) when one or more errors or conditions occur. When this indicator is on, a service request has been generated. This indicator stays on until the serial poll byte is read or all the conditions that caused SRQ have been cleared. See Section 11, “Status Structure,” for more information.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 10-12 Remote Operations Model 2750 Multimeter/Switch System User’s Manual These brackets indicate that IMMediate is implied (optional) and does not have to be used. Thus, the above command can be sent in one of two ways: INITiate or INITiate:IMMediate Notice that the optional command is used without the brackets. When using optional command words in your program, do not include the brackets.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Angle brackets < > Remote Operations 10-13 Angle brackets (< >) are used to denote a parameter type. Do not include the brackets in the program message. For example: RATio The indicates a Boolean-type parameter is required.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 10-14 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Long-form and short-form versions An SCPI command word can be sent in its long-form or short-form version. The command subsystem tables in Section 15 provide the long-form version. However, the short-form version is indicated by upper case characters.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-15 Program messages A program message is made up of one or more command words sent by the computer to the instrument. Each common command is a three letter acronym preceded by an asterisk (*). SCPI commands are categorized in the STATus subsystem and are used to explain how command words are structured to formulate program messages.
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 10-16 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Command path rules • • • • • Each new program message must begin with the root command, unless it is optional (e.g., [SENSe]). If the root is optional, simply treat a command word on the next level as the root. For fastest operation, do not send optional data. A colon (:) can be used at the beginning of a program message.
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2750-900-01.book Page 17 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-17 Response messages A response message is the message sent by the instrument to the computer in response to a query command program message. Sending a response message After sending a query command, the response message is placed in the Output Queue. When the Model 2750 is then addressed to talk, the response message is sent from the Output Queue to the computer.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 10-18 Remote Operations Model 2750 Multimeter/Switch System User’s Manual RS-232 interface operation Sending and receiving data The RS-232 interface transfers data using eight data bits, one stop bit, and no parity. Make sure the controller you connect to the multimeter also uses these settings. You can break data transmissions by sending a ^C (decimal 3) or ^X (decimal 18) character string to the instrument.
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Remote Operations 10-19 Signal handshaking (flow control) Signal handshaking between the controller and the instrument allows the two devices to communicate to each other regarding being ready or not ready to receive data. The Model 2750 does not support hardware handshaking (flow control).
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 10-20 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Selecting and configuring RS-232 interface After selecting (enabling) the RS-232 interface, you will then set the baud rate, flow control, and terminator. 1. 2. Press the SHIFT key and then the RS-232 key. The RS 232 ON or RS 232 OFF message will be displayed. If the RS-232 is already ON, press ENTER and proceed to step 3.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 10-22 Remote Operations Model 2750 Multimeter/Switch System User’s Manual Table 10-2 RS-232 connector pinout Pin number 1 2 3 4 5 6 7 8 9 1CTS Description No connection TXD, transmit data RXD, receive data No connection GND, signal ground Not used RTS, ready to send1 CTS, clear to send1 No connection and RTS are not used.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 11 Status Structure • Overview — Provides an operational overview of the status structure for the Model 2750. • Clearing registers and queues — Covers the actions that clear (reset) registers and queues. • Programming and reading registers — Explains how to program enable registers and read any register in the status structure.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 11-2 Status Structure Model 2750 Multimeter/Switch System User’s Manual Overview The Model 2750 provides a series of status registers and queues allowing the operator to monitor and manipulate the various instrument events. The status structure is shown in Figure 11-1. The heart of the status structure is the Status Byte Register.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 11-4 Status Structure Model 2750 Multimeter/Switch System User’s Manual Clearing registers and queues When the Model 2750 is turned on, the bits of all registers in the status structure are cleared (reset to 0), and the two queues are empty. Commands to reset the event and event enable registers, and the Error Queue are listed in Table 11-1.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-5 Programming and reading registers Programming enable registers The only registers that can be programmed by the user are the enable registers. All other registers in the status structure are read-only registers. The following explains how to ascertain the parameter values for the various commands used to program enable registers.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 11-6 Status Structure Model 2750 Multimeter/Switch System User’s Manual Reading registers Any register in the status structure can be read by using the appropriate query (?) command. The following explains how to interpret the returned value (response message). The actual query commands are covered later in this section (Table 11-2 through Table 11-5). The response message for a register query will be a decimal value.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-7 Status byte register The summary messages from the status registers and queues are used to set or clear the appropriate bits (B0, B2, B3, B4, B5, and B7) of the Status Byte Register. These summary bits do not latch, and their states (0 or 1) are solely dependent on the summary messages (0 or 1). For example, if the Standard Event Register is read, its register will clear.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 11-8 Status Structure Model 2750 Multimeter/Switch System User’s Manual Service request enable register The generation of a service request is controlled by the Service Request Enable Register. This register is programmed by you and is used to enable or disable the setting of bit B6 (RQS/MSS) by the Status Summary Message bits (B0, B2, B3, B4, B5, and B7) of the Status Byte Register.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-9 Status byte and service request commands The commands to program and read the Status Byte Register and Service Request Enable Register are listed in Table 11-2. For details on programming and reading registers, see “Programming enable registers,” page 11-5, and “Reading registers,” page 11-6.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM 11-10 Status Structure Model 2750 Multimeter/Switch System User’s Manual ' $INCLUDE: 'ieeeqb.bi' CLS CONST addr = 16 ' Clear PC output screen ' Set instrument address. ' ' Init GPIB. ' CALL initialize(21, 0) CALL transmit("unt unl listen " + STR$(addr) + " sdc unl", status%) ' Send Device Clear.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-11 Status register sets As shown in Figure 11-1, there are four status register sets in the status structure of the Model 2750: Standard Event Status, Operation Event Status, Measurement Event Status, and Questionable Event Status.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM 11-12 Status Structure • • • • • • • Model 2750 Multimeter/Switch System User’s Manual Bit B1 — Not used. Bit B2, Query Error (QYE) — Set bit indicates that you attempted to read data from an empty Output Queue. Bit B3, Battery-backed RAM Error (BRE) — Set bit indicates that the scan cannot be resumed (error +517) or there was a loss of data (error +516).
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-13 Figure 11-5 Operation event status (B15 - B11) Operation Idle Filt Trig Meas Condition (B10) (B9) (B8) (B7) (B6) (B5) (B4) (B3) (B2) (B1) (B0) Register (B15 - B11) Idle Filt Trig Meas (B10) (B9) (B8) (B7) (B6) (B5) (B4) (B3) (B2) (B1) (B0) Operation Event Register & & OR & & To Operation Summary Bit (OSB) of Status Byte Register.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM 11-14 Status Structure • • • • • • • NOTE • • • Model 2750 Multimeter/Switch System User’s Manual Bit B6, Buffer Notify (BN) — Set bit is a notification that the user-specified number of readings have been stored in the buffer. The TRACe:NOTify command specifies the number of stored readings that will set this bit (see Section 6 for details).
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2750-900-01.book Page 16 Wednesday, August 3, 2011 7:56 AM 11-16 Status Structure Model 2750 Multimeter/Switch System User’s Manual Questionable event register The used bits of the Questionable Event Register (Figure 11-7) are described as follows: • • • • • • • NOTE Bits B0 through B3 — Not used. Bit B4, Temperature Summary (Temp) — Set bit indicates that an invalid reference junction measurement has occurred for thermocouple temperature measurements. Bits B5, B6 and B7 — Not used.
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 11-18 Status Structure Model 2750 Multimeter/Switch System User’s Manual Condition registers As Figure 11-1 shows, each status register set (except the Standard Event Register set) has a condition register. A condition register is a real-time, read-only register that constantly updates to reflect the present operating conditions of the instrument.
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2750-900-01.book Page 19 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-19 Event enable registers As Figure 11-1 shows, each status register set has an enable register. Each event register bit is logically ANDed (&) to a corresponding enable bit of an enable register.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 11-20 Status Structure Model 2750 Multimeter/Switch System User’s Manual Queues The Model 2750 uses two queues, which are first-in, first-out (FIFO) registers: • • Output Queue — Used to hold reading and response messages. Error Queue — Used to hold error and status messages. The Model 2750 status model (Figure 11-1) shows how the two queues are structured with the other registers.
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2750-900-01.book Page 21 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Status Structure 11-21 On power-up, all error messages are enabled and will go into the Error Queue as they occur. Status messages are not enabled and will not go into the queue. As listed in Table 11-6, there are commands to enable and/or disable messages. For these commands, the parameter is used to specify which messages to enable or disable. The messages are specified by their codes.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 12-2 Common Commands Model 2750 Multimeter/Switch System User’s Manual Common commands (summarized in Table 12-1) are device commands that are common to all devices on the bus. These commands are designated and defined by the IEEE-488.2 standard. Table 12-1 IEEE-488.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual A *IDN? — identification query Common Commands 12-3 Reads identification code The identification code includes the manufacturer, model number, serial number, and firmware revision levels and is sent in the following format: KEITHLEY INSTRUMENTS INC., Model 2750, xxxxxxx, yyyyy/zzz Where: xxxxxxx is the serial number.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 12-4 Common Commands NOTE Model 2750 Multimeter/Switch System User’s Manual The following commands take a long time to process and may benefit from using *OPC or *OPC?: • • • • *RST and SYST:PRES *RCL and *SAV ROUT:MULT:CLOS and ROUT:MULT:OPEN – Only if the is long. CALC2:IMM and CALC2:IMM?– Only when performing the standard deviation calculation on a large buffer. A 10,000 point buffer takes around 5.75 seconds.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual NOTE Common Commands 12-5 The following commands take a long time to process and may benefit from using *OPC or *OPC?: • • • • *RST and SYST:PRES *RCL and *SAV ROUT:MULT:CLOS and ROUT:MULT:OPEN – Only if the is long. CALC2:IMM and CALC2:IMM?– Only when performing the standard deviation calculation on a large buffer. A 10,000 point buffer takes around 5.75 seconds.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 12-6 Common Commands 2. 3. NOTE Model 2750 Multimeter/Switch System User’s Manual Cancels all pending commands. Cancels response to any previously received *OPC and *OPC? commands. For RS-232 operation (and in some cases, GPIB operation), *OPC or *OPC? should be used with *RST, which is a slow responding command. Details on *OPC and *OPC? are provided in this section.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Common Commands 12-7 The Model 2750 has three overlapped commands: • • • :INITiate :INITiate:CONTinuous ON *TRG NOTE See *OPC, *OPC?, and *TRG for more information. The INITiate commands remove the Model 2750 from the idle state. The device operations of :INITiate are not considered complete until the Model 2750 returns to idle.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 13-2 SCPI Signal Oriented Commands Model 2750 Multimeter/Switch System User’s Manual The signal oriented measurement commands are used to acquire readings. You can use these high level instructions to control the measurement process. These commands are summarized in Table 13-1. NOTE When measurements are performed, the readings are fed to other enabled operations.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 13-4 SCPI Signal Oriented Commands Model 2750 Multimeter/Switch System User’s Manual Query CONFigure? Description included — When the parameter is included with CONFigure command, the specified channel(s) for the scanlist assumes the *RST default settings for the specified function. Range can also be set for the channel(s) by including the parameter. If the resolution parameter () is included, it will be ignored.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual SCPI Signal Oriented Commands 13-5 FETCh? Description This command requests the latest post-processed reading. After sending this command and addressing the Model 2750 to talk, the reading is sent to the computer. This command does not affect the instrument setup. This command does not trigger a measurement. The command simply requests the last available reading.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 13-6 SCPI Signal Oriented Commands Model 2750 Multimeter/Switch System User’s Manual If the instrument is in the idle state, INITiate takes the instrument out of the idle state. If continuous initiation is enabled, (INITiate:CONTinuous ON), then the INITiate command generates error -213 (init ignored). NOTE If continuous initiation is enabled, the READ? command will generate error -213 (init ignored).
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 13-8 SCPI Signal Oriented Commands Model 2750 Multimeter/Switch System User’s Manual When a MEASure? command is sent, the specified function is selected. If specified, range and resolution will also set. All other instrument settings related to the selected function are reset to the *RST defaults. NOTE If a function is not specified, the command executes as if the present function is specified.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM 14 FORMat and Miscellaneous SYSTem Commands • FORMat commands — Covers the SCPI commands to configure the format that readings are sent over the bus. • Miscellaneous SYSTem commands — Covers miscellaneous SYSTem commands.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 14-2 FORMat and Misc SYSTem Commands Model 2750 Multimeter/Switch System User’s Manual FORMat commands The commands in this subsystem are used to select the format for transferring data, Table 14-1, over the bus. Table 14-1 SCPI commands — data format Command Description FORMat[:DATA] [,] FORMat:ELEMents FORMat:BORDer Default Specify data format; ASCii, SREal, REAL, 32, ASCii DREal, or REAL, 64.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual FORMat and Misc SYSTem Commands 14-3 ASCII data format The ASCII data format is in a direct readable form for the operator. Most programming languages easily convert ASCII mantissa and exponent to other formats. However, some speed is compromised to accommodate the conversion. Figure 14-1 shows an example ASCII string that includes all the data elements.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 14-4 FORMat and Misc SYSTem Commands Model 2750 Multimeter/Switch System User’s Manual Figure 14-2 IEEE-754 data formats Header Byte 1 Byte 2 Byte 3 Byte 4 # 0 7 s 07 0 7 0 7 e 0 f s = sign bit (0 = positive, 1 = negative) e = exponent bits (8) f = fraction bits (23) Normal byte order shown. For swapped byte order, bytes sent in reverse order: Header, Byte 4, Byte 3, Byte 2, Byte 1.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual FORMat and Misc SYSTem Commands 14-5 FORMat:ELEMents Parameters READing UNITs TSTamp RNUMber CHANnel LIMits = DMM reading = Units = Timestamp = Reading number = Channel number = Limits reading The specified elements are included in the data string in response to FETCh?, READ?, MEASure?, and TRACe:DATA?. Note that each element in the item list must be separated by a comma (i.e.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 14-6 FORMat and Misc SYSTem Commands Model 2750 Multimeter/Switch System User’s Manual Limits — For the ASCII data format, limit test results are returned as a 4-bit binary number “abcd” where: a = High limit 2 b = Low limit 2 c = High limit 1 d = Low limit 1 A “0” indicates that the limit has passed, while a “1” indicates that the limit has failed.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual FORMat and Misc SYSTem Commands 14-7 Miscellaneous SYSTem commands SYSTem commands not covered in other sections of the manual are documented here. Table 15-7 lists all SYSTem commands and provides references on where to find more information. SYSTem:PRESet Returns the instrument to states optimized for front panel operation. SYSTem:PRESet defaults are listed in the SCPI tables in Section 15.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 14-8 FORMat and Misc SYSTem Commands Model 2750 Multimeter/Switch System User’s Manual The queue for the :KEY? query command can only hold one key-press. When :KEY? is sent and Model 2750 is addressed to talk, the key-press code number for the last key “pressed” is sent to the computer. SYSTem:BEEPer[:STATe] You can disable the beeper for limits and continuity tests.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM 15-2 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Reference tables Table 15-1 through Table 15-10 summarize the commands to operate the Model 2750 and Model 7700 switching module. NOTE The commands listed in the following tables pertain to operation of the Model 2750 and the Model 7700 switching module.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual SCPI Reference Tables 15-3 Table 15-1 CALCulate command summary Command Description CALCulate[1] Subsystem to control CALC 1: :FORMat Select math format (NONE, MXB, PERCent, or [<, clist>] RECiprocal). :FORMat? [] Query math format. :KMATh Path to configure math calculations: :MMFactor Set “m” factor for mx+b (-4294967295 to [, ] +4294967295).
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM 15-4 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-1 (continued) CALCulate command summary Command CALCulate3 :MLIMit :LATChed :OUTPut [:STATe] [:STATe]? :PULSe [:STATe] [:STATe]? :TIME Description Subsystem to control CALC 3 (limit test): Path for master limit command: Enable or disable master limit latch. Path for limit output commands: Enable or disable limit outputs.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM 15-6 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-2 DISPlay command summary Command DISPlay [:WINDow[1]] :TEXT :DATA :DATA? :STATe :STATe? :ENABle :ENABle? Description Default parameter Ref SCPI (see Note) Sec 1 Path to control user text messages. Define ASCII message “a” (up to 12 characters). Query text message. Enable or disable message mode. Query text message state.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual SCPI Reference Tables 15-7 Table 15-4 ROUTe command summary Command ROUTe :MONitor :STATe :STATe? :DATA? :POINts :POINts? :MONitor? :CLOSe :STATe? :ACONfigure :ACONfigure? :COUNt? :INTerval :INTerval? :CLOSe? :OPEN:ALL :MULTiple :OPEN :CLOSe :STATe? :CLOSe? Description Specify one channel to be monitored.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM 15-8 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-4 (continued) ROUTe command summary Command ROUTe :SCAN [:INTernal] [:INTernal]? :TSOurce :TSOurce? :NVOLatile :NVOLatile? :LSELect :LSELect? Description Path to configure scan: Specify list of channels to be scanned. Query scan list. Select trigger source to start the scan (IMM, or HLIM1, HLIM2, LLIM1, and LLIM2).
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2750-900-01.book Page 18 Wednesday, August 3, 2011 7:56 AM 15-18 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-5 (continued) SENSe command summary Command [SENSe[1]] :CONTinuity :THReshold :THReshold? Description Path to configure continuity test: Set threshold resistance in ohms (1 to 1000). Query threshold resistance. Default parameter Ref SCPI Sec 3 10 Notes: 1. CAVerage:DELay and RATio:DELay are coupled.
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2750-900-01.book Page 20 Wednesday, August 3, 2011 7:56 AM 15-20 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-7 SYSTem command summary Command SYSTem :PRESet :POSetup :POSetup? :FRSWitch? :BEEPer [:STATe] [:STATe]? :KCLick :KCLick? :KEY :KEY? :AZERo :STATe :STATe? :LSYNc [:STATe] [:STATe]? :LFRequency? :PCARdX Description Return to :SYST:PRES defaults. Select power-on setup: (RST, PRESet, SAV0, SAV1, or SAV2). Query power-on setup.
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2750-900-01.book Page 22 Wednesday, August 3, 2011 7:56 AM 15-22 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-7 (continued) SYSTem command summary Command SYSTem :END :SNOpen? :BANKs? :SWOpen? :BANKs? :CSOhms? :TIME :TIME? :DATE :DATE? :TSTamp :TYPE :TYPE? :RELative :RESet :RNUMber Description Default parameter Ref Request highest numbered digital output channel; 0 = digital input not supported.
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2750-900-01.book Page 23 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual SCPI Reference Tables 15-23 Table 15-7 (continued) SYSTem command summary Command SYSTem :RESet :ERRor? :CLEar :VERSion? :LOCal :REMote :RWLock Description Reset reading number. Next reading will be #1. Query (read) Error Queue. Clears messages from the Error Queue. Query rev level of SCPI standard. Take 2750 out of remote and restore operation of front panel controls (RS-232 only).
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2750-900-01.book Page 24 Wednesday, August 3, 2011 7:56 AM 15-24 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-8 TRACe command summary Command TRACe|:DATA :CLEar [:IMMediate] :AUTO :AUTO? :FREE? :POINts :POINts? :NOTify Description Use TRACe or DATA as root command. Path to clear the buffer. Clear the buffer. Enable or disable buffer auto-clear. Query state of buffer auto-clear. Query bytes available and bytes in use.
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2750-900-01.book Page 25 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual SCPI Reference Tables 15-25 Table 15-9 Trigger command summary Command INITiate [:IMMediate] :CONTinuous :CONTinuous? Description Subsystem command path: Initiate one trigger cycle. Enable or disable continuous initiation. Query continuous initiation. ABORt Reset trigger system. TRIGger[:SEQuence[1]] Path to program Trigger Layer: :COUNt Set measure count (1 to 110000, or INFinity).
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2750-900-01.book Page 26 Wednesday, August 3, 2011 7:56 AM 15-26 SCPI Reference Tables Model 2750 Multimeter/Switch System User’s Manual Table 15-10 UNIT command summary Command UNIT :TEMPerature :TEMPerature? :VOLTage [:DC] [, ] :DB :REFerence :REFerence? [:DC]? [] :AC [, ] :DB :REFerence :REFerence? :AC? [] Description Select temperature units (C, CEL, F, FAR, or K). Query temperature units. Path to configure voltage units.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM B-2 Model 7700 Connection Guide Model 2750 Multimeter/Switch System User’s Manual Card configuration — schematic Figure B-1 shows a simplified schematic diagram of the Model 7700 module. As shown, the Model 7700 has channels that are grouped into two banks of ten channels (twenty channels total). Backplane isolation is provided for each bank. Each bank also includes separate cold junction reference points.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM B-4 Model 7700 Connection Guide Model 2750 Multimeter/Switch System User’s Manual Connections and wiring WARNING The following information is intended for qualified service personnel. Do not make or break switching module connections unless qualified to do so.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Model 7700 Connection Guide B-5 Screw terminals Figure B-2 shows how to access the screw terminals on the Model 7700. Channel designations for the screw terminals are contained in Figure B-3.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM B-10 Model 7700 Connection Guide Model 2750 Multimeter/Switch System User’s Manual Figure B-9 Voltage connections (DC or AC) DC Voltage AC Voltage HI + Channel 1 LO (Channels 2–19) HI + Channel 20 LO Connection log Make a copy of Table B-1 and affix it to the cover of the Model 7700. Use this to record connection information and channel descriptions as needed.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM D-2 Signal Processing Sequence and Data Flow Model 2750 Multimeter/Switch System User’s Manual Signal processing sequence Basic signal processing The signal is applied to the multimeter input via front panel input terminals or a switching module. When a channel is closed or scanned, the signal connected to that channel (or channel-pair for 4-wire measurements) is connected to the input.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Signal Processing Sequence and Data Flow D-3 Signal processing using instrument features Figure D-2 shows the processing sequence for an input signal with various instrument features enabled. If a feature is not enabled, the reading simply falls through to the next enabled feature or to the display.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM D-4 Signal Processing Sequence and Data Flow Model 2750 Multimeter/Switch System User’s Manual OComp (offset-compensated ohms) The Model 2750 performs a normal ohms measurement by sourcing a known current (I), measuring the voltage (V), and then calculating the resistance (R = V/I). Offsetcompensated ohms cancels the effects of thermal EMFs which can adversely affect lowresistance measurements.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Signal Processing Sequence and Data Flow D-5 Math Next in the signal processing sequence is a Math operation (mX+b, Percent, or Reciprocal). These math operations allow you to mathematically manipulate the reading (X) that is applied to this block in the flowchart. With one of the Math functions enabled, the math result is calculated as shown in Figure D-2.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM D-6 Signal Processing Sequence and Data Flow Model 2750 Multimeter/Switch System User’s Manual Signal processing using Ratio or Ch Avg With a switching module installed, the ratio or average of two channels can be calculated. Figure D-3 shows where Ratio or Ch Avg is calculated in the signal processing sequence.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Signal Processing Sequence and Data Flow D-7 Data flow (remote operation) Remote operation can be used with triggering configured to perform a specified number of measurements and then stop. The various read commands (SENS:DATA?, FETCh?, READ?, MEAS?, CALC2:DATA?, TRACe:DATA?, and CALC1:DATA?) return the data array(s) acquired during the measurement cycle.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM D-8 Signal Processing Sequence and Data Flow NOTE Model 2750 Multimeter/Switch System User’s Manual For the following discussion, a “data array” is defined as the group of data elements that are included with each measured reading. Each data array includes the reading as well as the channel, reading number, units, timestamp, and limits result (see “FORMat:ELEMents ,” page 14-5, for details).
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Signal Processing Sequence and Data Flow D-9 [SENS[1]]:DATA[LATest]? [SENS[1]]:DATA:FRESh? These commands are used to return (read) the last processed data array stored in the sample buffer. [SENS[1]]:DATA[:LATest]? This command returns (reads) one data array. It returns the last processed data array stored in the sample buffer.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM D-10 Signal Processing Sequence and Data Flow NOTE Model 2750 Multimeter/Switch System User’s Manual For more information on FETCh?, READ? and MEASure?, see Section 13, “SCPI Signal Oriented Measurement Commands.” FETCh? With no Math function enabled, this command reads the data arrays stored in the sample buffer.
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2750-900-01.book Page 11 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Signal Processing Sequence and Data Flow D-11 CALC[1]:DATA[:LATest]? CALC[1]:DATA:FRESh? These two commands are similar to the LATest? and FRESh? commands for the SENSe1 subsystem, except that returned data arrays are the result of the math calculation. See [SENS[1]]:DATA[:LATest]? and [SENS[1]]:DATA:FRESh? for details on the differences between LATest? and FRESh?.
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM D-12 Signal Processing Sequence and Data Flow Model 2750 Multimeter/Switch System User’s Manual CALC2:IMM? CALC2:IMM CALC2:DATA? Statistical information (minimum, maximum, mean, standard deviation, and peak-to-peak) is available for the readings stored in the buffer (data store).
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Signal Processing Sequence and Data Flow D-13 Scanning For remote operation, scanning is normally performed with continuous initiation disabled (INIT:CONT OFF). The sample count (SAMP:COUNt) specifies the number of channels to scan and store in the buffers (sample buffer and data store), and the trigger count (TRIG:COUNt) specifies the number of scans to perform.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM E-2 Measurement Considerations Model 2750 Multimeter/Switch System User’s Manual Measurement considerations Low-level voltage measurements made using the Model 2750 can be adversely affected by various types of noise or other unwanted signals that can make it very difficult to obtain accurate voltage readings.
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Measurement Considerations E-3 Thermoelectric generation Figure E-1 shows a representation of how thermal EMFs are generated. The test leads are made of the A material, while the source under test is the B material. The temperatures between the junctions are shown as T1 and T2.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM E-4 Measurement Considerations Model 2750 Multimeter/Switch System User’s Manual Minimizing thermal EMFs To minimize thermal EMFs, use only copper wires, lugs, and test leads for the entire test setup. Also, it is imperative that all connecting surfaces are kept clean and free of oxides. As noted in Table E-1, copper-to-copper oxide junctions can result in thermal EMFs as high as 1mV/°C.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Measurement Considerations E-5 Source resistance noise Noise present in the source resistance is often the limiting factor in the ultimate resolution and accuracy of Model 2750 measurements. The following paragraphs discuss the generation of Johnson noise as well as ways to minimize such noise.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM E-6 Measurement Considerations Model 2750 Multimeter/Switch System User’s Manual Magnetic fields When a conductor loop cuts through magnetic lines of force, a very small current is generated. This phenomenon will frequently cause unwanted signals to occur in the test leads of a test system.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Measurement Considerations E-7 Ground loops When two or more instruments are connected together, care must be taken to avoid unwanted signals caused by ground loops. Ground loops usually occur when sensitive instrumentation is connected to other instrumentation with more than one signal return path such as power line ground.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM E-8 Measurement Considerations Model 2750 Multimeter/Switch System User’s Manual Figure E-3 shows how to connect several instruments together to eliminate this type of ground loop problem. Here, only one instrument is connected to power line ground. Ground loops are not normally a problem with instruments like the Model 2750 that have isolated LO terminals. However, all instruments in the test setup may not be designed in this manner.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Measurement Considerations E-9 Shielding WARNING Do not float input LO more than 30V rms, 42.4V peak above earth ground with an exposed shield connected to input LO. To avoid a possible shock hazard, surround the LO shield with a second safety shield that is insulated from the inner shield. Connect this safety shield to safety earth ground using #18 AWG minimum wire before use.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM E-10 Measurement Considerations Model 2750 Multimeter/Switch System User’s Manual Meter loading Loading of the voltage source by the Model 2750 becomes a consideration for high source resistance values. As the source resistance increases, the error caused by meter loading increases. Figure E-5 shows the method used to determine the percent error due to meter loading.
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2750-900-01.book Page 1 Wednesday, August 3, 2011 7:56 AM F Temperature Equations • Thermocouple equation — Documents the ITS-90 inverse function polynomial and the coefficients to calculate thermocouple temperature. • Thermistor equation — Documents the Steinhart-Hart equation which is used to calculate thermistor temperature. • RTD equation — Documents the Callendar-Van Dusen equation which is used to calculate the temperature vs. resistance readings listed in the RTD reference tables.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM F-2 Temperature Equations Model 2750 Multimeter/Switch System User’s Manual Thermocouple equation The Model 2750 uses the ITS-90 inverse function coefficients for the polynomial to calculate thermocouple temperature. The Model 2750 measures the thermocouple voltage, and then calculates temperature (in °C) as follows: t90 = c0 + c1E + c2E2 + c3E3 ... ciEi where: t90 is the calculated temperature in °C. c0, c1, c2, c3 ...
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2750-900-01.book Page 3 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Temperature Equations F-3 Table F-2 Type E inverse function polynomial -200°C to 0°C (-8,825µV to 0µV) c0 = c1 = c2 = c3 = c4 = c5 = c6 = c7 = c8 = c9 = Error: 0.0 1.697 728 8 × -4.351 497 0 × -1.585 969 7 × -9.250 287 1 × -2.608 431 4 × -4.136 019 9 × -3.403 403 0 × -1.156 486 0 × 0°C to 1,000°C (0µV to 76,373µV) 0.0 1.705 703 5 × 10-2 -2.330 175 9 × 10-7 6.543 558 5 × 10-12 -7.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM F-4 Temperature Equations Model 2750 Multimeter/Switch System User’s Manual Table F-4 Type K inverse function polynomial -200°C to 0°C (-5,891µV to 0µV) c0 = c1 = c2 = c3 = c4 = c5 = c6 = c7 = c8 = c9 = Error: 0.0 2.517 346 2 × -1.166 287 8 × -1.083 363 8 × -8.977 354 0 × -3.734 237 7 × -8.663 264 3 × -1.045 059 8 × -5.192 057 7 × 0°C to 500°C (0µV to 20,644µV) 0.0 2.508 355 2 × 10-2 7.860 106 2 × 10-8 -2.503 131 2 × 10-10 8.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Temperature Equations F-5 Table F-6 Type R inverse function polynomial -50°C to 250°C (-226µV to 1,923µV) c0 = c1 = c2 = c3 = c4 = c5 = c6 = c7 = c8 = c9 = c10 = Error: 0.0 1.889 138 0 × 10-1 -9.383 529 0 × 10-5 1.306 861 9 × 10-7 -2.270 358 0 × 10-10 3.514 565 9 × 10-13 -3.895 390 0 × 10-16 2.823 947 1 × 10-19 -1.260 728 1 × 10-22 3.135 361 1 × 10-26 -3.318 776 9 × 10-30 0.02°C to -0.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM F-6 Temperature Equations Model 2750 Multimeter/Switch System User’s Manual Table F-8 Type T inverse function polynomial -200°C to 0°C (-5,603µV to 0µV) c0 = c1 = c2 = c3 = c4 = c5 = c6 = c7 = Error: 0.0 2.594 919 2 × 10-2 -2.131 696 7 × 10-7 7.901 869 2 × 10-10 4.252 777 7 × 10-13 1.330 447 3 × 10-16 2.024 144 6 × 10-20 1.266 817 1 × 10-24 0.04°C to -0.02°C 0°C to 400°C (0µV to 20,872µV) 0.0 2.592 800 × 10-2 -7.602 961 × 10-7 4.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Temperature Equations F-7 Selecting a thermistor — The thermistor’s manufacturer’s specified curve fitting values (A, B, and C) may not be exactly the same as the ones used by the Model 2750. If they are not exactly the same, perform the following steps to select a thermistor to use with the Model 2750: NOTE 1. 2. 3. 4.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM F-8 Temperature Equations Model 2750 Multimeter/Switch System User’s Manual RTD equation The temperature vs.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual Temperature Equations F-9 C = -1 (0.00385)(0.10863) (1e-8) = -1 (0.000418)(1e-8) = - 4.18e-12 The resistance of the RTD at 100°C (R100) is then calculated as follows: R100 = R0 [1 + AT + BT2 + CT3(T-100)] = 100 {1 + [(0.00391)(100)] + [(-5.77e-7)(1002)]+ [(-4.18e-12)(1003)(100-100)]} = 100 [1 + 0.391 + (-0.006) + 0] = 100 (1.385) = 138.
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2750-900-01.book Page 2 Wednesday, August 3, 2011 7:56 AM G-2 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual Introduction The IEEE-488 bus is a communication system between two or more electronic devices. A device can be either an instrument or a computer. When a computer is used on the bus, it serves as a supervisor of the communication exchange between all the devices and is known as the controller.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM G-4 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual There are two categories of controllers: system controller and basic controller. Both are able to control other instruments, but only the system controller has the absolute authority in the system. In a system with more than one controller, only one controller may be active at any given time. Certain protocol is used to pass control from one controller to another.
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2750-900-01.book Page 5 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual IEEE-488 Bus Overview G-5 Bus management lines The five bus management lines help to ensure proper interface control and management. These lines are used to send the uniline commands. ATN (Attention) — The ATN state determines how information on the data bus is to be interpreted. IFC (Interface Clear) — The IFC line controls clearing of instruments from the bus.
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2750-900-01.book Page 6 Wednesday, August 3, 2011 7:56 AM G-6 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual Once all NDAC and NRFD are properly set, the source sets DAV low, indicating to accepting devices that the byte on the data lines is now valid. NRFD will then go low, and NDAC will go high once all devices have accepted the data. Each device will release NDAC at its own rate, but NDAC will not be released to go high until all devices have accepted the data byte.
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2750-900-01.book Page 7 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual IEEE-488 Bus Overview G-7 Table G-1 IEEE-488 bus command summary Command type Command State of ATN line Comments Uniline REN (Remote Enable) EOI IFC (Interface Clear) ATN (Attention) SRQ X X X Low X Set up devices for remote operation. Marks end of transmission. Clears interface. Defines data bus contents. Controlled by external device.
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2750-900-01.book Page 8 Wednesday, August 3, 2011 7:56 AM G-8 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual Uniline commands ATN, IFC, and REN are asserted only by the controller. SRQ is asserted by an external device. EOI may be asserted either by the controller or other devices depending on the direction of data transfer. The following is a description of each command. Each command is sent by setting the corresponding bus line true.
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2750-900-01.book Page 9 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual IEEE-488 Bus Overview G-9 Addressed multiline commands Addressed commands are multiline commands that must be preceded by the device listen address before that instrument will respond to the command in question. Note that only the addressed device will respond to these commands. Both the commands and the address preceding it are sent with ATN true.
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2750-900-01.book Page 10 Wednesday, August 3, 2011 7:56 AM G-10 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual Common commands Common commands are commands that are common to all devices on the bus. These commands are designated and defined by the IEEE-488.2 standard. Generally, these commands are sent as one or more ASCII characters that tell the device to perform a common operation, such as reset.
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D2 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 D3 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 D1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 D0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Column Row GET TCT* SDC PPC* GTL 0 (B) Command ADDRESSED COMMAND GROUP (ACG) NUL SOH STX ETX EOT ENQ ACK BEL BS HT LF VT FF CR SO SI 0 (A) X 0 0 0 SPE SPD DCL PPU* LLO 1 (B) Command UNIVERSAL COMMAND GROUP (UCG) DLE DC1 DC2 DC3 DC4 NAK SYN ETB CAN EM SUB ESC FS GS RS US 1 (A) X 0 0 1 Primary Address SP !
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2750-900-01.book Page 12 Wednesday, August 3, 2011 7:56 AM G-12 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual Typical command sequences For the various multiline commands, a specific bus sequence must take place to properly send the command. In particular, the correct listen address must be sent to the instrument before it will respond to addressed commands. Table G-3 lists a typical bus sequence for sending the addressed multiline commands.
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2750-900-01.book Page 13 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual IEEE-488 Bus Overview G-13 IEEE command groups Command groups supported by the Model 2750 are listed in Table G-5. Common commands and SCPI commands are not included in this list.
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2750-900-01.book Page 14 Wednesday, August 3, 2011 7:56 AM G-14 IEEE-488 Bus Overview Model 2750 Multimeter/Switch System User’s Manual Interface function codes The interface function codes, which are part of the IEEE-488 standards, define an instrument’s ability to support various interface functions and should not be confused with programming commands found elsewhere in this manual. The interface function codes for the Model 2750 are listed in Table G-6.
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2750-900-01.book Page 15 Wednesday, August 3, 2011 7:56 AM Model 2750 Multimeter/Switch System User’s Manual IEEE-488 Bus Overview G-15 PP (Parallel Poll Function) — The instrument does not have parallel polling capabilities (PP0). DC (Device Clear Function) — DC1 defines the ability of the instrument to be cleared (initialized). DT (Device Trigger Function) — DTI defines the ability of the Model 2750 to have readings triggered.
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2750-900-01.book Page 4 Wednesday, August 3, 2011 7:56 AM Introduction G-2 IEEE-488 bus configuration G-3 IEEE-488 Bus Overview G-1 IEEE-488 connector 10-5 IEEE-488.
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7.5X9BackCovr 12-06.qxd 1/10/07 2:45 PM Page 1 Specifications are subject to change without notice. All Keithley trademarks and trade names are the property of Keithley Instruments, Inc. All other trademarks and trade names are the property of their respective companies. A G R E A T E R M E A S U R E O F C O N F I D E N C E Keithley Instruments, Inc. Corporate Headquarters • 28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168 • 1-888-KEITHLEY • www.keithley.