Computer-Based Instruments NI 5911 User Manual High-Speed Digitizer with FLEX ADC™ NI 5911 User Manual June 2001 Edition Part Number 322150D-01
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Important Information Warranty The NI 5911 is warranted against defects in materials and workmanship for a period of one year from the date of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace equipment that proves to be defective during the warranty period. This warranty includes parts and labor.
Compliance FCC/Canada Radio Frequency Interference Compliance* Determining FCC Class The Federal Communications Commission (FCC) has rules to protect wireless communications from interference. The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrial-commercial locations only) or Class B (for use in residential or commercial locations). Depending on where it is operated, this product could be subject to restrictions in the FCC rules.
Canadian Department of Communications This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations. Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada. Compliance to EU Directives Readers in the European Union (EU) must refer to the Manufacturer's Declaration of Conformity (DoC) for information** pertaining to the CE Mark compliance scheme.
Conventions The following conventions are used in this manual: » The » symbol leads you through nested menu items and dialog box options to a final action. The sequence File»Page Setup»Options directs you to pull down the File menu, select the Page Setup item, and select Options from the last dialog box. This icon denotes a note, which alerts you to important information. This icon denotes a caution, which advises you of precautions to take to avoid injury, data loss, or a system crash.
Contents Chapter 1 Taking Measurements with the NI 5911 Installing the NI 5911 ....................................................................................................1-1 Connecting Signals ........................................................................................................1-1 Acquiring Data with Your NI 5911 ...............................................................................1-3 Programmatically Controlling Your NI 5911.............................................
Contents RTSI Bus and Clock PFI ............................................................................................... 2-11 PFI Lines ......................................................................................................... 2-11 PFI Lines as Inputs ........................................................................... 2-12 PFI Lines as Outputs......................................................................... 2-12 Synchronization .........................................
Taking Measurements with the NI 5911 1 Thank you for buying a National Instruments (NI) 5911 digitizer, featuring the FLEX ADC. This chapter provides information on installing, connecting signals to, and acquiring data from your NI 5911. Installing the NI 5911 There are two main steps involved in installation: 1. Install the NI-SCOPE driver software. You use this driver to write programs to control your NI 5911 in different application development environments (ADEs).
Chapter 1 Taking Measurements with the NI 5911 CH0 PFI1 PFI2 (DIN) Figure 1-1. NI 5911 Connectors 9 6 1 2 3 +5 Volts (Fused) GND Reserved 4 5 6 8 7 5 4 2 1 Reserved Reserved PFI 2 3 7 8 9 Reserved Reserved Reserved Figure 1-2. 9-Pin Mini Circular DIN Connector NI 5911 User Manual 1-2 ni.
Chapter 1 Taking Measurements with the NI 5911 Acquiring Data with Your NI 5911 You can acquire data either programmatically—by writing an application for your NI 5911—or interactively with the Scope Soft Front Panel. Programmatically Controlling Your NI 5911 To help you get started programming your NI 5911, NI-SCOPE comes with examples that you can use or modify.
2 Hardware Overview This chapter includes an overview of the NI 5911, explains the operation of each functional unit making up your NI 5911, and describes the signal connections. Figure 2-1 shows a block diagram of the NI 5911. Analog Input Connector AC/DC Coupling Protect/ Calibration Mux PGIA A/D Converter 100 MHz, 8-Bit Noise Shaper Calibration Generator Timing IO/ Memory Control Digital IO Connector Digital Signal Processor Capture Memory Reference Clock Data Figure 2-1.
Chapter 2 Hardware Overview Differential Input When measuring high dynamic range signals, ground noise is often a problem. The PGIA of the NI 5911 allows you to make noise-free signal measurements. The PGIA differential amplifier efficiently rejects any noise present on the ground signal. Internal to the PGIA, the signal presented at the negative input is subtracted from the signal presented at the positive input. As shown in Figure 2-2, this subtraction removes ground noise from the signal.
Chapter 2 Hardware Overview Input Ranges To optimize the ADC resolution, you can select different gains for the PGIA. In this way, you can scale your input signal to match the full input range of the converter. The NI 5911 PGIA offers seven different input ranges, from ±0.1 V to ±10 V, as shown in Table 2-1. Table 2-1. Input Ranges for the NI 5911 Range Input Protection Threshold ±10 V ±10 V ±5 V ±5 V ±2 V ±5 V ±1 V ±5 V ±0.5 V ±5 V ±0.2 V ±5 V ±0.
Chapter 2 Hardware Overview if the device has 1 MΩ output impedance, your measured signal will be one-half the actual signal value. Input Bias The inputs of the PGIA typically draw an input bias current of 1 nA at 25 °C. Attaching a device with a very high source impedance can cause an offset voltage to be added to the signal you measure, according to the formula Rs × 1 nA, where Rs is the external source impedance.
Chapter 2 Hardware Overview analysis, distortion analysis, and other measurements for which high resolution is crucial. Oscilloscope Mode The ADC converts at a constant rate of 100 MS/s, but you can choose to store only a fraction of these samples into memory at a lower rate. This allows you to store waveforms using fewer data points and decreases the burden of storing, analyzing, and displaying the waveforms.
Chapter 2 Hardware Overview Table 2-2. Available Sampling Rates and Corresponding Bandwidth in Flexible Resolution Mode Sampling Rate Resolution Bandwidth 12.5 MS/s 11 Bits 3.75 MHz 5 MS/s 14 Bits 2 MHz 2.5 MS/s 15.5 Bits 1 MHz 1 MS/s 17.5 Bits 400 kHz 500 kS/s 18 Bits 200 kHz 200 kS/s 18.5 Bits 80 kHz 100 kS/s 19 Bits 40 kHz 50 kS/s 19.5 Bits 20 kHz 20 kS/s 20.
Chapter 2 Hardware Overview Calibration The NI 5911 can be calibrated for very high accuracy and resolution due to an advanced calibration scheme. There are two different types of calibration: internal, or self, calibration and external calibration. A third option, internal restore, restores factory settings and should be used only in the event of a self-calibration failure. Internal calibration is performed via a software command that compensates for drifts caused by environmental temperature changes.
Chapter 2 Hardware Overview • The linearity of the ADC is calibrated using an internal sinewave generator as reference. • The time-to-digital converter used for RIS measurements is calibrated. Caution Do not apply high-amplitude or high-frequency signals to the NI 5911 during internal calibration. For optimal calibration performance, disconnect the input signal from the NI 5911.
Chapter 2 Analog Input High Level Gain + COMP Analog Trigger Circuit Low Level Hardware Overview ATC_OUT COMP – a. Analog Trigger Circuit Software ATC_OUT RTSI <0..6> PFI1, PFI2 Trigger 7 2 Arm b. Trigger and Arm Sources Figure 2-3. Trigger Sources Analog Trigger Circuit The analog trigger on the NI 5911 operates by comparing the current analog input to an onboard threshold voltage. This threshold voltage is the trigger value, and can be set within the current input range in 170 steps.
Chapter 2 Hardware Overview Trigger Hold-Off Trigger hold-off is the minimum length of time (in seconds) from an accepted trigger to the start of the next record. In other words, when a trigger is accepted, the trigger counter is loaded with the desired hold-off time. After completing its current record, the digitizer records no data and accepts no triggers until the hold-off counter runs out. When the counter runs out, the next record begins and a trigger may be accepted.
Chapter 2 Hardware Overview Multiple-Record Acquisitions After the trigger has been received and the posttrigger samples have been stored, the NI 5911 can be configured to begin another acquisition that is stored in another onboard memory record. This is a multiple-record acquisition. To perform multiple-record acquisitions, configure the NI 5911 to the number of records you want to acquire before starting the acquisition.
Chapter 2 Hardware Overview PFI Lines as Inputs You can select PFI1 or PFI2 as inputs for a trigger or a reference clock. Please see the Synchronization section below for more information about the use of reference clocks in the NI 5911. PFI Lines as Outputs You can select PFI1 or PFI2 to output several digital signals. Reference Clock is a 10 MHz clock that is synchronous to the 100 MHz sample clock on the NI 5911.
A Specifications This appendix lists the specifications of the NI 5911. These specifications are typical at 25 °C unless otherwise stated. Acquisition System Bandwidth .............................................. 100 MHz maximum, see Table 2-2, Available Sampling Rates and Corresponding Bandwidth in Flexible Resolution Mode Number of channels ............................... 1 Number of flexible resolution ADC....... 1 Max sample rate .....................................
Appendix A Specifications Sample Rate Mode Effective Resolution 20 kS/s Flexible Resolution 20.5 Bits 10 kS/s Flexible Resolution 21 Bits * 1
Appendix A Specifications Input Range Noise Referred to Input ±0.5 V 148 dBfs/ Hz ±0.2 V 140 dBfs/ Hz ±0.1 V 134 dBfs/ Hz Acquisition Characteristics Accuracy DC gain accuracy ................................... ±0.05% signal ±0.0001% fs for all input ranges at 1 MS/s in flexible resolution mode DC offset accuracy................................. ±0.1 mV ±0.01% fs for all input ranges at 1 MS/s in flexible resolution mode Input coupling ........................................
Appendix A Specifications Filtering Sampling Frequency Filter Mode Bandwidth Ripple Alias Attenuation 100/n* MS/s Oscilloscope 100 MHz ±3 dB N/A 12.5 MS/s Flexible Resolution 3.75 MHz ±0.2 dB –60 dB 5 MS/s Flexible Resolution 2 MHz ±0.1 dB –70 dB 2.5 MS/s Flexible Resolution 1 MHz ±0.05 dB –80 dB 1 MS/s Flexible Resolution 400 kHz ±0.005 dB –80 dB 500 kS/s Flexible Resolution 200 kHz ±0.005 dB –80 dB 200 kS/s Flexible Resolution 80 kHz ±0.
Appendix A Specifications Sampling Frequency Bandwidth Noise Density Total Noise 1 MS/s 400 kHz –160 dBfs/ Hz –104 dBfs 500 kS/s 200 kHz –160 dBfs/ Hz –107 dBfs 200 kS/s 80 kHz –160 dBfs/ Hz –111 dBfs 100 kS/s 40 kHz –160 dBfs/ Hz –114 dBfs 50 kS/s 20 kHz –160 dBfs/ Hz –117 dBfs 20 kS/s 8 kHz –160 dBfs/ Hz –121 dBfs 10 kS/s 4 kHz –160 dBfs/ Hz –124 dBfs * 1
Appendix A Specifications Clock input tolerance (as slave)..............10 MHz ±100 ppm Clock jitter ..............................................<75 pSrms, independent of reference clock source Clock compatibility ...............................TTL for both input and output Interpolator resolution (repetitive only) ......................................1 ns Sampling clock frequencies Oscilloscope mode...........................100 MHz/n, where 1
Appendix A Specifications Sensitivity............................................... 170 steps in full-scale voltage range TRIG input range ................................... ±5 V (without external attenuation) TRIG input impedance........................... 1 MΩ ± 1% in parallel with 30 pF ± 15 pF TRIG input protection ............................ ±42 V [(DC + peak AC) < 10 kHz, without external attenuation] Acquisition Modes RIS .........................................................
Appendix A Specifications Operating Environment Multiple NI 5911s in the same computer may raise operating temperatures beyond specification and give rise to imprecise data. NI strongly recommends leaving an empty PCI slot between multiple NI 5911s or adding a fan. Note Ambient temperature ..............................5 to 40 °C Relative humidity ...................................10% to 90%, noncondensing Storage Environment Ambient temperature ..............................
Technical Support Resources B Web Support National Instruments Web support is your first stop for help in solving installation, configuration, and application problems and questions. Online problem-solving and diagnostic resources include frequently asked questions, knowledge bases, product-specific troubleshooting wizards, manuals, drivers, software updates, and more. Web support is available through the Technical Support section of ni.com. NI Developer Zone The NI Developer Zone at ni.
Appendix B Technical Support Resources Worldwide Support National Instruments has offices located around the world to help address your support needs. You can access our branch office Web sites from the Worldwide Offices section of ni.com. Branch office Web sites provide up-to-date contact information, support phone numbers, e-mail addresses, and current events.
Glossary Prefix Meanings Value p- pico- 10 –12 n- nano- 10 –9 µ- micro- 10 – 6 m- milli- 10 –3 k- kilo- 10 3 M- mega- 10 6 G- giga- 10 9 Symbols % percent + positive of, or plus – negative of, or minus / per ° degree ± plus or minus Ω ohm A A amperes A/D analog to digital AC alternating current © National Instruments Corporation G-1 NI 5911 User Manual
Glossary AC coupled the passing of a signal through a filter network that removes the DC component of the signal ADC analog-to-digital converter—an electronic device, often an integrated circuit, that converts an analog voltage to a digital number ADC resolution the resolution of the ADC, which is measured in bits. An ADC with16 bits has a higher resolution, and thus a higher degree of accuracy, than a 12-bit ADC.
Glossary clock hardware component that controls timing for reading from or writing to groups CMRR common-mode rejection ratio—a measure of an instrument’s ability to reject interference from a common-mode signal, usually expressed in decibels (dB) counter/timer a circuit that counts external pulses or clock pulses (timing) coupling the manner in which a signal is connected from one location to another D dB decibel—the unit for expressing a logarithmic measure of the ratio of two signal levels: dB=
Glossary F filtering a type of signal conditioning that allows you to filter unwanted signals from the signal you are trying to measure fs full-scale—total voltage in the input range.
Glossary interrupt level the relative priority at which a device can interrupt ISA industry standard architecture K k kilo—the standard metric prefix for 1,000, or 103, used with units of measure such as volts, hertz, and meters kS 1,000 samples L LabVIEW laboratory virtual instrument engineering workbench—a graphical programming ADE developed by National Instruments LSB least significant bit M m meters MB megabytes of memory memory buffer see buffer MS million samples MSB most signifi
Glossary N noise an undesirable electrical signal—noise comes from external sources such as the AC power line, motors, generators, transformers, fluorescent lights, soldering irons, CRT displays, computers, electrical storms, welders, radio transmitters, and internal sources such as semiconductors, resistors, and capacitors. Noise corrupts signals you are trying to send or receive. Nyquist frequency a frequency that is one-half the sampling rate. See also Nyquist Sampling Theorem.
Glossary pretriggering the technique used on a device to keep a buffer filled with data, so that when the trigger conditions are met, the sample includes the data leading up to the trigger condition PXI PCI eXtensions for Instrumentation. PXI is an open specification that builds off the CompactPCI specification by adding instrumentation-specific features.
Glossary sense in four-wire resistance the sense measures the voltage across the resistor being excited by the excitation current settling time the amount of time required for a voltage to reach its final value within specified limits source impedance a parameter of signal sources that reflects current-driving ability of voltage sources (lower is better) and the voltage-driving ability of current sources (higher is better) system noise a measure of the amount of noise seen by an analog circuit or an
Glossary V V volts VAC volts alternating current VDC volts direct current Verror voltage error VI virtual instrument—(1) a combination of hardware and/or software elements, typically used with a PC, that has the functionality of a classic stand-alone instrument (2) a LabVIEW software module (VI), which consists of a front panel user interface and a block diagram program Vrms volts, root mean square value W waveform shape the shape the magnitude of a signal creates over time working voltage t
Index A conventions used in the manual, vi customer education, B-1 AC coupling, 2-4 accuracy characteristics, A-3 acquisition multiple record, 2-11 Scope Soft Front Panel, 1-3 acquisition characteristics specifications accuracy, A-3 common-mode characteristics, A-3 distortion, A-5 dynamic range, A-4 filtering, A-4 acquisition modes specifications, A-7 acquisition system specifications, A-1 analog trigger circuit, 2-9 arming.
Index G input protection circuits, 2-4 input ranges, 2-3 installing NI 5911, 1-1 grounding considerations, 2-2 H M hardware overview See also specifications acquisition system PFI lines, 2-11 triggering and arming, 2-8 block diagram of NI 5911, 2-1 calibration, 2-7 differential programmable gain input amplifier (PGIA) AC coupling, 2-4 differential input, 2-2 grounding considerations, 2-2 input bias, 2-4 input impedance, 2-3 input protection, 2-4 input ranges, 2-3 noise-free signal measurement (figure)
Index O specifications acquisition characteristics accuracy, A-3 common-mode characteristics, A-3 distortion, A-5 dynamic range, A-4 filtering, A-4 acquisition modes, A-7 acquisition system, A-1 calibration, A-8 EMC compliance, A-8 operating environment, A-8 physical, A-7 power requirements, A-7 storage environment, A-8 timebase system, A-5 triggering systems, A-6 storage environment specifications, A-8 synchronization, 2-12 system integration, by National Instruments, B-1 operating environment specifica
