EXCELLENCE IN MAGNETICS AND CRYOGENICS AMI MODEL 135/136 LIQUID HELIUM LEVEL INSTRUMENT INSTALLATION, OPERATION, AND MAINTENANCE INSTRUCTIONS American Magnetics, Inc. PO Box 2509, 112 Flint Road, Oak Ridge, TN 37831-2509, Tel: 865 482-1056, Fax: 865 482-5472 Rev.
Declaration of Conformity Application of Council Directives: Low Voltage Directive 72/23/EEC EMC Directive 89/336/EEC Manufacturer’s Name: American Magnetics, Inc. Manufacturer’s Address: 112 Flint Road, P.O. Box 2509 Oak Ridge, TN 37831-2509 U.S.A.
Model 135/136 Liquid Helium Level Instrument Instrument Configuration AMI Order Number:_____________________ Shipping Date:_________________________ Model/Serial #:_________________________ Firmware Revision:_____________________ Input Power Requirements:___________________________________________________________ Configuration Notes: _____________________________________________________________________________________ _____________________________________________________________________________________
Table of Contents 1 2 3 4 Introduction .............................................................................. 1 1.1 Model 135/136 Features............................................................ 1 1.2 Model 135 Front Panel Layout ............................................... 3 1.3 Model 135 Rear Panel Layout ................................................ 4 1.4 Model 136 Front Panel Layout ................................................ 5 1.5 Model 136 Rear Panel Layout ........
Table of Contents 5 6 4.2 IEEE-488 Communication Option ..........................................28 4.2.1 Command/return termination characters...................28 4.2.2 Communicating with the Model 135/136 ....................28 4.2.3 IEEE-488 Communication DIP Switch Settings ........30 4.2.4 IEEE-488 Command Set Reference ............................32 4.2.5 Serial Poll Status Byte.................................................36 4.3 Error Codes..................................................
Foreword Purpose and Scope This manual contains the operation and maintenance instructions for the American Magnetics, Inc. Model 135/136 Liquid Level Instrument. The manual outlines the instructions for instrument use in various system designs.
Foreword Applicable Hardware Applicable Hardware The Model 135/136 has been designed to operate with an AMI Liquid Helium Level Sensor. Operation with other equipment is not recommended and may void the warranty. General Precautions Cryogen Safety Personnel handling cryogenic liquids should be thoroughly instructed and trained as to the nature of the liquids. Training is essential to minimize accidental spilling.
Foreword Safety Summary 2. Do not apply heat. Loosen any clothing that may restrict circulation. Apply a sterile protective dressing to the affected area. 3. If the skin is blistered or there is any chance that the eyes have been affected, get the patient immediately to a physician for treatment. Containers of cryogenic liquids are self pressurizing (as the liquid boils off, vapor pressure increases). Hoses or lines used to transfer these liquids should never be sealed at both ends (i.e.
Foreword Safety/Manual Legend rupture disks, etc.) included in the cryostat and top plate assembly are necessary. Recommended Safety Equipment First Aid kit Fire extinguisher rated for class C fires Leather gloves Face shield Signs to indicate that there are potentially dangerous cryogens in use in the area.
1 Introduction 1.1 Model 135/136 Features The American Magnetics, Inc. (AMI) Model 135/136 Liquid Helium Level Instrument is an advanced, microprocessor-based instrument utilizing AMI’s patented sample-and-hold principle with automatic helium sensor vacuum burnout protection. The instruments are designed for unattended operation in systems where it is important to monitor and/or control the liquid helium levels and minimize the liquid helium losses.
Introduction Features innovative microprocessor-based circuitry detects incipient sensor burnout and de-energizes the sensor before damage can occur. A 5% increase in sensor resistance will trigger this protection, causing the current to be switched off for 6 seconds before attempting to resume normal operation. 1.1.4 Floating supply Due to safety concerns, the high voltage power supply used for the sensor is a floating supply.
Introduction Model 135 Front Panel Layout 1.2 Model 135 Front Panel Layout 1 2 32:(5 6(1625 &855(17 3 100.0 O +, 6(732,17 /2 6(732,17 /(1*7+ ,17(59$/ 6,/(1&( 2 6 Rev.
Introduction Model 135 Rear Panel Layout 1.3 Model 135 Rear Panel Layout 1 RS-232 ON $0(5,&$1 0$*1(7,&6 ,1& 2$. 5,'*( 71 8 6 $ J8 S11 &20081,&$7,216 /,1( +] 9$ 0$; 6(1625 - - 9 2 4 9 4 3 1 Optional RS-232 or GPIB communications port (RS-232 shown) 3 Sensor input DB-9 female connector (see the Appendix for the pinout diagram) 2 Auxiliary DB-9 male connector (see Appendix for pinout) 4 Power cord connector Rev.
Introduction Model 136 Front Panel Layout 1.4 Model 136 Front Panel Layout 4 1 2 3 32:(5 6(1625 &855(17 ),// O 5 +, 6(7 $ 32,176 % /2 /(1*7+ ,17(59$/ 6,/(1&( } &/26(' Rev. 3 +, /(9(/ $ % /2 /(9(/ 100.
Introduction Model 136 Rear Panel Layout 1.5 Model 136 Rear Panel Layout 1 RS-232 ON $0(5,&$1 0$*1(7,&6 ,1& 2$.
Introduction Specifications 1.6 Model 135/136 Specifications @ 25 °C Level Measurements Resolution: 0.1%, 0.1 cm, or 0.1 in Accuracya: ± 0.5% of active sensor length Linearity: ± 0.1% Sensor Current: 75 mA nominal Sensor Voltage: approx.
Introduction Specifications Physical Dimensions (Standard): Weight (Standard): Dimensions (Rack Mount): 97 mm H x 213 mm W x 273 mm D (3.8" H x 8.4" W x 10.75" D) 1.8 kg (4.0 lbs.) for Model 135 2.0 kg (4.3 lbs.) for Model 136 89 mm H x 483 mm W x 273 mm D (3.5" H x 19" W x 10.75" D) Weight (Rack Mount): 2.3 kg (5.0 lbs.) Ambient Temperature: Operating: 0 °C to 50 °C (32 °F to 122 °F) Nonoperating: −20 °C to 60 °C (−4 °F to 140 °F) Environmental Relative Humidity: 0 to 95%; non-condensing a.
2 Installation Warning Before energizing the instrument, the earth ground of the power receptacle must be verified to be at earth potential and able to carry the rated current of the power circuit. Using extension cords should be avoided; however, if one must be used, ensure the ground conductor is intact and capable of carrying the rated current.
Installation Sensor Preparation 2.2 Rack Mounting the Instrument If the instrument has a rack mount chassis, follow the following procedure: a. Attach the rack mount adapter pieces to the instrument by first removing the four screws on the side of the instrument that attach the cover to the chassis. Attach the rack mount adapter pieces to the sides of the instrument by reinstalling the screws. b.
Installation Sensor Preparation where R is the maximum allowable resistance (in ohms) for each lead wire from the instrument to the sensor, and L is the active length of the connected helium level sensor in inches. Please note that the maximum allowable active sensor length for input line voltages less than 105 VAC or 210 VAC is 64 inches. Tables for active sensor length vs. lead wire distance are provided below.
Installation Installing a Fill Valve 2.4 Installing the Optional Solenoid-Operated Fill Valve 0RGHO Install the solenoid-operated fill valve by connecting the valve power cable to the AC controller output receptacle on the rear panel of the instrument. The standard AMI supplied valve has a 9/32 inch orifice and the input and output are tapped for 3/8 NPT. Caution When using a solenoid-operated control valve with the Model 136, ensure the valve is configured for the operating voltage of the Model 136.
Installation Verifying power requirements 2.6 Connecting the Instrument to Power Warning The Model 135/136 operates on 50-60 Hz power and may be configured for 100-120 or 200-240 VAC ±10%. The power requirements for the instrument is marked on the calibration sticker on the bottom of the instrument. Verify that your instrument is configured for your power source prior to plugging in the line cord. Do not fail to connect the input ground terminal securely to an external earth ground.
Installation Verifying power requirements 14 Rev.
3 Operation This section describes the front panel display and control functions for the Model 135/136. In addition to the front panel operation described, the remote communication ports provide methods for performing similar operations and querying the current state of the instrument. Refer to the Remote Interface Reference section beginning on page 21 for more details regarding the communication functions. 3.
Operation Normal Operational Mode Note If the displayed level reading is below the LO SETPOINT level or exceeds the HI SETPOINT, an audible alarm will sound. To silence the alarm, rotate the control mode rotary switch on the front panel to the SILENCE position. 3.2.2 Configure the active length setting Note The Model 135/136 instrument is calibrated at the factory.
Operation Normal Operational Mode a. When the measured liquid level exceeds the HI setpoint, the HI LEVEL LED on the front panel is energized and a set of relay contacts are closed on the 9-pin D connector J2 on the rear panel (see the Appendix for the pinout). When the level reaches or falls below the HI setpoint, the LED is extinguished and the relay contacts open. b.
Operation Normal Operational Mode c. In addition to the LED functions, the controller output receptacle may be energized and de-energized as discussed in step 5 below. Note The A setpoint must always be above the B setpoint. The firmware does not allow these setpoints to be reversed. Both setpoints may be set from 0% to 100% of the LENGTH setting as long as A > B. 3.2.
Operation Normal Operational Mode 3.2.6 Configure the sample time interval setting To adjust the sample time interval, place the control mode rotary switch in the INTERVAL position. Use the RAISE/LOWER toggle switch to adjust the time interval in the same manner as described in paragraph 3.2.2. The instrument is shipped with the time interval set for 1.0 minutes. This value can be changed to any setting between 0 and 600 minutes.
Operation Dirty Sensor Operational Mode or 4-20 mA analog signal corresponding to 0-100% of liquid level. Refer to the Appendix for the pinout diagram of connector J2. 3.3 Dirty Sensor Operational Mode AMI expects the helium level sensor to be reasonably clean and free from oil, water, ice, etc. for proper operation. However, it is recognized that some experiments might result in some material being deposited on the sensor wire. Ice formation at some point on the sensor is a typical occurrence.
4 Remote Interface Reference 4.1 Serial Communication/Data Logger Option The serial communication/data logger option provides a 25-pin D-type connector on the rear panel of the instrument for serial communications and data logger function. 4.1.1 Serial port connector and cabling An IBM-compatible computer’s serial port can be directly connected to the Model 135/136 via a standard PC modem cable.
Remote Interface Reference Serial Communication DIP Switch Settings of only termination characters. Otherwise, the shared input/output command buffer of the Model 135/136 may become corrupted. No other form of flow control is supported. 4.1.3 ON Serial Communication DIP Switch Settings 1 1234567 8 0 The 8 DIP switches located on the rear panel of the Model 135/136 are used to control various parameters of the serial interface. Switches 6 through 8 control the baud rate of the interface.
Remote Interface Reference Serial Communication DIP Switch Settings 4.1.3.3 Data logger function Switch 1 of the communications DIP switch controls the data logger function. This feature is normally used with a printer rather than a host computer, since a computer can be more usefully programmed utilizing the available command set. The data logger function generates a time relative to instrument power-up and a corresponding helium level.
Remote Interface Reference Serial Command Set Reference 4.1.4 Serial Command Set Reference All commands sent to the Model 135/136 are processed and the Model 135/ 136 responds with the answer. If the command is invalid, the Model 135/ 136 will respond with -8. All return values are terminated with (i.e. a carriage return followed by a linefeed). For those commands that do not return a value, the Model 135/136 will return the termination only. 4.1.4.
Remote Interface Reference Serial Command Set Reference 4.1.4.
Remote Interface Reference Serial Command Set Reference the sampling interval to 0.1 minutes (or 0.1 hours if so configured, see page 53). The SAVE command saves the HI, LO, A, B, INTERVAL, LENGTH, and current remote units settings to permanent memory. These settings are then recalled each time the power is turned off and then reapplied to the instrument. If the configuration is changed from the front panel, the settings are automatically saved to permanent memory. 4.1.4.
Remote Interface Reference Serial Command Set Reference 4.1.4.4 Commands for performing level measurements Command: LEVEL Function: Returns the liquid helium level in the current units Returns: Command: HOLD Function: Immediately ceases level measurements Returns: Command: MEASURE Function: Initiates level measurement in the current sampling mode Returns: The LEVEL command returns the liquid helium level in the current units selected.
Remote Interface Reference IEEE-488 Communication Option 4.2 IEEE-488 Communication Option The IEEE-488 communication option provides a GPIB connector on the rear panel of the instrument for IEEE-488 (GPIB, HPIB) communications. 4.2.1 Command/return termination characters All commands are transmitted and received as ASCII values and are case insensitive. The Model 135/136 always transmits and EOI as the termination for return data.
Remote Interface Reference Communicating with the Model 135/136 via IEEE-488 Begin Send Command SRQ Asserted? Y N Another Command? Wait for or Read SRQ N Y Get Response End N Y (-8) Error? Error Routine Basic communication flow diagram for IEEE-488 commands. Rev.
Remote Interface Reference IEEE-488 Communication DIP Switch Settings 4.2.3 ON IEEE-488 Communication DIP Switch Settings 1 12345 0 The 5 DIP switches located on the rear panel of the Model 135/136 are used to control the IEEE-488 interface. Switches 1 through 5 control the IEEE-488 bus address of the unit. 4.2.3.1 IEEE-488 primary bus address The Model 135/136 primary bus address is controlled by switches 1 through 5 of the communication DIP switch on the rear panel.
Remote Interface Reference IEEE-488 Communication DIP Switch Settings DIP switch Rev.
Remote Interface Reference IEEE-488 Command Set Reference 4.2.4 IEEE-488 Command Set Reference All commands sent to the Model 135/136 are processed and the Model 135/ 136 responds with the answer. If the command is invalid, the Model 135/ 136 will respond with -8. All return values are terminated with (linefeed) and EOI asserted. For those commands that do not return a value, the Model 135/136 will echo the command string in the return message.
Remote Interface Reference IEEE-488 Command Set Reference 4.2.4.
Remote Interface Reference IEEE-488 Command Set Reference the sampling interval to 0.1 minutes (or 0.1 hours if so configured, see page 53). The SAVE command saves the HI, LO, A, B, INTERVAL, LENGTH, and current remote units settings to permanent memory. These settings are then recalled each time the power is turned off and then reapplied to the instrument. If the configuration is changed from the front panel, the settings are automatically saved to permanent memory. 4.2.4.
Remote Interface Reference IEEE-488 Command Set Reference 4.2.4.5 Commands for performing level measurements Command: LEVEL Function: Returns the liquid helium level in the current units Returns: Command: HOLD Function: Immediately ceases level measurements Returns: HOLD Command: MEASURE Function: Initiates level measurement in the current sampling mode Returns: MEASURE The LEVEL command returns the liquid helium level in the current units selected.
Remote Interface Reference Serial Poll Status Byte 4.2.5 Serial Poll Status Byte The IEEE-488 serial poll status byte (spoll byte) can be used to obtain information about the state of the instrument. Bit 7 of the status byte is reserved for SRQ. The remaining bits are used to provide custom information as shown in the table below.
Remote Interface Reference Error Codes 4.3 Error Codes The Model 135/136 returns specific error codes for invalid commands and/ or arguments. If an error condition is returned, the command is not processed and the configuration of the instrument is not modified. The table below provides a list of error codes, their meaning, and any associated limits. The error codes are common to both the serial and IEEE488 communication options.
Remote Interface Reference Error Codes 38 Rev.
5 Virtual Instrument Operation In order to make the communications options easier to use for the customer, AMI provides a LabVIEW®-based interface for remote monitoring and control of the Model 135/136. LabVIEW is a virtual instrument (VI) development and deployment software tool produced and marketed by National Instruments. LabVIEW is available on several platforms including Microsoft Windows™, Microsoft Windows NT™, Apple Macintosh™, Sun Solaris™, and HP-UX™.
Virtual Instrument Operation RS-232 Virtual Instrument front panel of the actual instrument to the mode desired by the operator. The VI’s representation of the sampling mode toggle switch overrides any actual front panel setting by forcing the actual instrument to perform an immediate measurement when placed in the UPDATE position. 5.1.1 Launching and initializing the RS-232 VI First, make sure the Model 135/136 is connected to a COM port on the host computer and that the instrument is powered on.
Virtual Instrument Operation RS-232 Virtual Instrument VI Function Serial Port Send.vi Manages sending and receiving of ASCII strings from the actual instrument. 0RGHO Set 136 A via Serial Port.vi Configures the A setpoint. 0RGHO Set 136 B via Serial Port.vi Configures the B setpoint. Set 13X Interval via Serial Port.vi Configures the sampling interval setting. Set 13X HI via Serial Port.vi Configures the HI setpoint. Set 13X Length via Serial Port.vi Configures the sensor length.
Virtual Instrument Operation RS-232 Virtual Instrument and the baud rate to which the Model 135/136 is set (see page 22 for instructions on setting the baud rate). The user may then start the VI. Please refer to your LabVIEW documentation for instructions on how to start and control the execution of VI’s. 5.1.
Virtual Instrument Operation IEEE-488 Virtual Instrument 5.2 IEEE-488 Virtual Instrument The IEEE-488 (or GPIB) VI functions nearly identically to the RS-232 VI with a few exceptions. The VI library, provided in the file MODEL13X.LLB, for the IEEE-488 virtual instrument contains the following files: VI Function 13X Alarms.vi Manages alarm functions for 135/136. Config 13X via GPIB.vi Initializes actual instrument from VI configuration. Convert from CM.
Virtual Instrument Operation IEEE-488 Virtual Instrument with multiple devices on one GPIB bus. The exact design of the nonexclusive operation is dependent upon the specific devices you may have connected to the bus. When running the VI it is important to operate the instrument using the VI and not via the actual instrument front panel. Otherwise, the VI and the actual instrument may not be synchronized.
Virtual Instrument Operation IEEE-488 Virtual Instrument enter all data in the control fields (Sensor Length, Hi Setpoint, etc.) in the indicated units. The user should also select the correct GPIB bus and primary address (see page 30 for instructions on setting the Model 135/136 primary address). If only one GPIB interface is present in the host computer, the GPIB bus is normally set to 0.
Virtual Instrument Operation Running multiple GPIB devices string. Any settings changed by the VI virtual panel toggle switches or control fields are saved in permanent memory in the actual instrument. The control fields and toggle switches function whether the VI is run exclusively or non-exclusively on the GPIB bus. If the VI is executed exclusively, then the VI may be gracefully stopped by using the STOP toggle switch in the lower left corner of the VI.
6 Service Guide The procedures in this section should only be performed by Qualified Service Personnel (QSP). 6.1 Troubleshooting Procedures The following paragraphs serve as an aid to assist QSP in troubleshooting a potential problem with the Model 135/136. If the QSP is not comfortable with troubleshooting the system, you may contact an Authorized AMI Technical Support Representative for assistance. Refer to “Additional Technical Support” on page 53.
Service Guide No level reading 6.1.1 No level reading 1. Ensure that the sensor is immersed in liquid helium. If the sensor is immersed and/or cooled, then proceed to step 2. Note When the sensor is not cooled, the instrument will enter into the sensor burnout protection mode and turn off the sensor current. Refer to paragraph 3.1 of the Operation section for a description of this mode. 2. Check the sensor connections.
Service Guide Erratic or erroneous level reading Warning This procedure is to be performed only when the instrument is completely de-energized by removing the power-cord from the power receptacle. Failure to do so could result in personnel coming in contact with high voltages capable of producing life-threatening electrical shock. a. Ensure the instrument is de-energized by disconnecting the power cord from the power source.
Service Guide Erratic or erroneous level reading 3. Check for a dirty sensor. If the sensor collects oil, water, etc., the sensor could possibly not operate correctly. Refer to page 20 for a discussion of the optional dirty sensor operational mode. 4. Ensure the sensor is not installed in a restricted area which prohibits the level of helium around the area of the sensor to be an accurate representation of the level to be measured.
Service Guide Unit not responding to communications 6.1.4 Unit not responding to communications 1. Verify your communications cable integrity and wiring. See the Appendix for DB-25 to DB-9 translation for RS-232 cables. 2. Check to make sure you are sending the correct termination to the instrument. If you are using the RS-232 option, make sure the echo feature is set correctly for your application and the baud rate matches the setting of the host device.
Service Guide Custom Instrument Configurations 6.2 Custom Instrument Configurations 6.2.1 Modifying the line voltage requirements Warning Before removing the cover of the instrument, remove the power from the instrument by disconnecting the power cord from the power receptacle. Failure to do this could expose the user to high voltages and could result in life-threatening electrical shock.
Service Guide Return Authorization 6.2.3 Changing time adjustments from minutes to hours Warning Before removing the cover of the instrument, remove the power from the instrument by disconnecting the power cord from the power receptacle. Failure to do this could expose the user to high voltages and could result in life-threatening electrical shock. The Model 135/136 can be configured to use hours for the time settings, as opposed to the factory setting of minutes.
Service Guide Return Authorization 54 Rev.
Appendix A.1 4-20 ma Current Loop Option The 4-20 mA output utilizes pins 1 and 2 of connector J2. When the Model 135/136 is configured for the 4-20 mA current loop option, the 0-10 VDC analog output from connector J2 is not available. The figure below shows the wiring diagram and the voltage requirements for the power supply and receiver.
Appendix Sensor Connector J1 Wiring A.2 Sensor Connector J1 Wiring Pin Function 1 Sensor + Red) I ( 2 Not used 3 Not used 4 Not used 5 Not used 6 Sensor V- (Yellow) 7 Sensor I- (Black) 8 Sensor V+ (Blue) 9 Not used Pin 1 J1 Warning Although the sensor connector terminals are isolated from earth ground and therefore touching one terminal is not hazardous, the voltage between terminals is at a hazardous potential.
Appendix Auxiliary connector J2 pinout A.3 Auxiliary Connector J2 Pinout Pin Function 1 4-20 mA current loop input (optional feature) 2 4-20 mA current loop output (optional feature) 3 0-10 VDC output (optional feature) 4 0-10 VDC or 4-20 mA common (optional feature) 5&6 Lo level relay contacts (dry) 7&8 Hi level relay contacts (dry) 9 Not used Pin 1 J2 The HI level and LO level contacts are provided for external use by the customer.
Appendix RS-232 Cable DB-25 to DB-9 Translation A.4 RS-232 Cable DB-25 to DB-9 Translation DB-25 Pin DB-9 Pin 2 3 3 2 4 7 5 8 6 6 7 5 8 1 20 4 22 9 All other pins on the DB-25 connector are unused. This is standard PC modem cable wiring. A.
Index A R AMI Internet e-mail address AMI WWW address 53 applicable hardware vi audible alarm 16 53 rack mounting 10 rear panel layout 4, 6 return authorization 53 S safety equipment v iii legend v iii sensor connector J1 wiring 56 sensor lead wire sizing 10 sensor preparation 10 serial communications baud rate 22 cables 5 8 commands 24 data logger 23 DIP switch 2 2 echo function 22 error codes 37 interactive communication 21 terminators 2 1 serial port connector/cables 21 specifications 7 B burnout p
Index 60 Rev.