National Instruments NI PXI-7851 User Manual
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National Instruments NI PXI-7851 User Manual

National Instruments NI PXI-7851 User Manual

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  • Page 1 PXI-7851...
  • Page 2 Intelligent DAQ NI R Series Intelligent DAQ User Manual NI 781xR, 783xR, NI 784xR, and NI 785xR Devices R Series Intelligent DAQ User Manual June 2008 370489F-01...
  • Page 3 Thailand 662 278 6777, Turkey 90 212 279 3031, United Kingdom 44 (0) 1635 523545 For further support information, refer to the Technical Support and Professional Services appendix. To comment on National Instruments documentation, refer to the National Instruments Web site at and enter ni.com/info the info code feedback ©...
  • Page 4 Instruments Corporation. National Instruments respects the intellectual property of others, and we ask our users to do the same. NI software is protected by copyright and other intellectual property laws. Where NI software may be used to reproduce software or other materials belonging to others, you may use NI software only to reproduce materials that you may reproduce in accordance with the terms of any applicable license or other legal restriction.
  • Page 5 These classes are known as Class A (for use in industrial-commercial locations only) or Class B (for use in residential or commercial locations). All National Instruments (NI) products are FCC Class A products. Depending on where it is operated, this Class A product could be subject to restrictions in the FCC rules. (In Canada, the Department of Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.) Digital...

  • Page 6: Table Of Contents

    NI 7830R Overview.......................2-3 NI 7831R/7833R Overview ...................2-4 NI 784xR Overview.......................2-4 NI 785xR Overview.......................2-4 Analog Input (Multifunction R Series Only) ..............2-4 Input Modes.....................2-5 Input Range .....................2-5 Connecting Analog Input Signals ..................2-6 © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 7 Contents Types of Signal Sources ....................2-8 Floating Signal Sources .................. 2-8 Ground-Referenced Signal Sources ..............2-8 Input Modes........................2-8 Differential Connection Considerations (DIFF Input Mode) ......2-10 Differential Connections for Ground-Referenced Signal Sources ... 2-11 Differential Connections for Nonreferenced or Floating Signal Sources ..............

  • Page 8: About This Manual

    About This Manual This manual describes the electrical and mechanical aspects of the National Instruments 781xR/783xR/784xR/785xR devices and contains information about programming and using the devices. Conventions The following conventions appear in this manual: <> Angle brackets that contain numbers separated by an ellipsis represent a range of values associated with a bit or signal name—for example,...

  • Page 9: Related Documentation

    • NI R Series Intelligent DAQ Specifications—Lists the specifications of the NI 781xR/783xR/784xR/785xR R Series devices. This document is available at Start»All Programs»National Instruments»NI-RIO. This document is also available at ni.com/manuals • LabVIEW FPGA documentation –...
  • Page 10 To access this document, refer to . In ni.com/manuals LabVIEW 8.0 or later, you can also view the LabVIEW Manuals directory that contains this document by selecting Start»All Programs»National Instruments»LabVIEW»LabVIEW Manuals. © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 11: Additional Resources

    • PXI Software Specification Revision 2.1 • National Instruments Example Finder—LabVIEW contains an extensive library of VIs and example programs for use with R Series devices. To access the NI Example Finder, open LabVIEW and select Help»Find Examples, then select Hardware Input and Output»...

  • Page 12: Introduction

    You can change the functionality of the FPGA on the R Series device in LabVIEW using the LabVIEW FPGA Module to create and download a custom virtual © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 13: Using Pxi With Compactpci

    Chapter 1 Introduction instrument (VI) to the FPGA. Using the FPGA Module, you can graphically design the timing and functionality of the R Series device. If you only have LabVIEW but not the FPGA Module, you cannot create new FPGA VIs, but you can create VIs that run on Windows or a LabVIEW Real-Time (RT) target to control existing FPGA VIs.

  • Page 14: Overview Of Reconfigurable I/O

    You can configure the behavior of the reconfigurable FPGA to match the requirements of the measurement and control system. You can implement this user-defined behavior as an FPGA VI to create an application-specific I/O device. © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 15: Flexible Functionality

    Chapter 1 Introduction Flexible Functionality Flexible functionality allows the NI 78xxR to match individual application requirements and to mimic the functionality of fixed I/O devices. For example, you can configure an R Series device in one application for three 32-bit quadrature encoders and then reconfigure the R Series device in another application for eight 16-bit event counters.

  • Page 16: Reconfigurable I/O Architecture

    The functions use varied amounts of logic. You can place useful applications in the FPGA. How much FPGA space your application requires depends on your need for I/O recovery, I/O, and logic algorithms. © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 17: Reconfigurable I/O Applications

    Chapter 1 Introduction The FPGA does not retain the VI when the R Series device is powered off, so you must reload the VI each time you power on the device. You can load the VI from onboard flash memory or from software over the bus interface. One advantage to using flash memory is that the VI can start executing almost immediately after power up, instead of waiting for the computer to completely boot and load the FPGA VI.

  • Page 18: Labview Real-Time Module

    Note If you use the R Series device without the FPGA Module, you can use the RIO Device Setup utility, available by selecting Start»All Programs»National Instruments» NI-RIO»RIO Device Setup to download precomplied FPGA VIs to the flash memory of the R Series device. This utility installs with NI-RIO. You also can use the utility to...

  • Page 19: Cables And Accessories

    Chapter 1 Introduction Cables and Accessories National Instruments offers a variety of products you can use with R Series devices, including cables, connector blocks, and other accessories, as shown in Table 1-3. Table 1-3. R Series Connectivity Options Cable Connector...

  • Page 20: Custom Cabling

    The pollution has no influence. • Pollution Degree 2 means that only nonconductive pollution occurs in most cases. Occasionally, however, a temporary conductivity caused by condensation must be expected. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 21 Chapter 1 Introduction • Pollution Degree 3 means that conductive pollution occurs, or dry, nonconductive pollution occurs that becomes conductive due to condensation. You must insulate signal connections for the maximum voltage for which the device is rated. Do not exceed the maximum ratings for the device. Do not install wiring while the device is live with electrical signals.
  • Page 22 Measurement Category IV is for measurements performed at the primary electrical supply installation (<1,000 V). Examples include electricity meters and measurements on primary overcurrent protection devices and on ripple control units. © National Instruments Corporation 1-11 R Series Intelligent DAQ User Manual...

  • Page 23: Hardware Overview Of The Ni 78 Xx R

    Interface RIO Devices Address/Data Digital I/O (40) PXI Local Bus (NI PXI-781x R Only) Digital I/O (40) RTSI Bus Digital I/O (40) Figure 2-1. NI 781 x R Block Diagram © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 24 Chapter 2 Hardware Overview of the NI 78xxR Calibration Configuration Flash DACs Input Mux Control Memory 16-Bit Instrumentation AI– Ampliflier – x4 Channels Input Mode Mux AISENSE User- Voltage Temperature AIGND Control Reference Sensor Configurable Data/Address/ Interface FPGA on RIO Control Calibration Address/Data...

  • Page 25: Ni 7811R Overview

    The NI 7830R has four independent, 16-bit AI channels; four independent, 16-bit AO channels; 56 bidirectional DIO lines that you can configure individually for input or output; and a Virtex-II XC2V1000 FPGA. © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 26: Ni 7831R/7833R Overview

    Chapter 2 Hardware Overview of the NI 78xxR NI 7831R/7833R Overview The NI 7831R/7833R each have eight independent, 16-bit AI channels; eight independent, 16-bit AO channels; 96 bidirectional DIO lines that you can configure individually for input or output; and a Virtex-II XC2V3000 FPGA.

  • Page 27: Input Modes

    The negative input of the instrumentation amplifier on each AI channel connects internally to the AISENSE input pin. Input Range The NI 783xR/784xR/785xR AI range is fixed at ±10 V. © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 28: Connecting Analog Input Signals

    Chapter 2 Hardware Overview of the NI 78xxR Connecting Analog Input Signals The AI signals for the NI 783xR/784xR/785xR are AI<0..n>+, AI<0..n>–, AIGND, and AISENSE. For the NI 7830R, n=4. For the NI 7831R/7833R/784xR/785xR, n=8. The AI<0..n>+ and AI<0..n>– signals are connected to the eight AI channels of the NI 783xR/784xR/785xR.
  • Page 29 If you have a grounded source, do not reference the signal to AIGND. You can avoid this reference by using DIFF or NRSE input modes. © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 30: Types Of Signal Sources

    Chapter 2 Hardware Overview of the NI 78xxR Types of Signal Sources When configuring the input channels and making signal connections, you must first determine whether the signal sources are floating or ground referenced. The following sections describe these two signal types. Floating Signal Sources A floating signal source is not connected to the building ground system but instead has an isolated ground-reference point.
  • Page 31 AI< i > – – AISENSE AISENSE – – Single-Ended— Nonreferenced AIGND< i > (NRSE) AIGND< i > See text for information on bias resistors. Figure 2-5. Summary of Analog Input Connections © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 32: Differential Connection Considerations (Diff Input Mode)

    Chapter 2 Hardware Overview of the NI 78xxR Differential Connection Considerations (DIFF Input Mode) In DIFF input mode, the NI 783xR/784xR/785xR measures the difference between the positive and negative inputs. DIFF input mode is ideal for measuring ground-referenced signals from other devices. When using DIFF input mode, the input signal connects to the positive input of the instrumentation amplifier and its reference signal, or return, connects to the negative input of the instrumentation amplifier.

  • Page 33: Differential Connections For Ground-Referenced Signal Sources

    V– (input signals) are both within their specified input ranges. Refer to the NI R Series Intelligent DAQ Specifications, available at , for more information about input ranges. ni.com/manuals © National Instruments Corporation 2-11 R Series Intelligent DAQ User Manual...

  • Page 34: Differential Connections For Nonreferenced Or Floating Signal Sources

    Chapter 2 Hardware Overview of the NI 78xxR Differential Connections for Nonreferenced or Floating Signal Sources Figure 2-7 shows how to connect a floating signal source to a channel on the NI 783xR/784xR/785xR configured in DIFF input mode. Bias Resistors AI–...

  • Page 35: Single-Ended Connection Considerations

    The leads connecting the signal to the NI 783xR/784xR/785xR are less than 3 m (10 ft). • The input signal can share a common reference point with other signals. © National Instruments Corporation 2-13 R Series Intelligent DAQ User Manual...

  • Page 36: Single-Ended Connections For Floating Signal Sources (Rse Input Mode)

    Chapter 2 Hardware Overview of the NI 78xxR Use DIFF input connections for greater signal integrity for any input signal that does not meet the preceding conditions. You can configure the NI 783xR/784xR/785xR channels in software for RSE or NRSE input modes. Use the RSE input mode for floating signal sources.

  • Page 37: Single-Ended Connections For Grounded Signal Sources (Nrse Input Mode)

    Source – Measured – Voltage – Common- Mode Noise and Ground AISENSE – Potential AIGND I/O Connector NRSE Input Mode Selected Figure 2-9. Single-Ended Input Connections for Ground-Referenced Signals © National Instruments Corporation 2-15 R Series Intelligent DAQ User Manual...

  • Page 38: Common-Mode Signal Rejection Considerations

    Chapter 2 Hardware Overview of the NI 78xxR Common-Mode Signal Rejection Considerations Figure 2-6 and Figure 2-9 show connections for signal sources that are already referenced to some ground point with respect to the NI 783xR/784xR/785xR. In these cases, the instrumentation amplifier can reject any voltage caused by ground potential differences between the signal source and the device.

  • Page 39: Connecting Analog Output Signals

    DGND and DIO<0..15>. The DIO<0..n> signals make up the DIO port and DGND is the ground reference signal for the DIO port. The NI 781xR has four RDIO connectors for a total of 160 DIO lines. The © National Instruments Corporation 2-17 R Series Intelligent DAQ User Manual...
  • Page 40 Chapter 2 Hardware Overview of the NI 78xxR NI 7830R has one RMIO and one RDIO connector for a total of 56 DIO lines. The NI 7831R/7833R/784xR/785xR has one RMIO and two RDIO connectors for a total of 96 DIO lines. Refer to Figure A-1, NI 781xR Connector Pin Assignments and Locations,...
  • Page 41 The NI 78xxR SHC68-68-RDIO cable contains individually shielded bundles that route each digital signal on an individually shielded pair of wires, and each signal is twisted with its own wire to digital ground. © National Instruments Corporation 2-19 R Series Intelligent DAQ User Manual...
  • Page 42 Chapter 2 Hardware Overview of the NI 78xxR The SHC68-68-RDIO was designed specifically for R Series devices and is the NI-recommended cable for digital applications. If you are using the SH68-C68-S cable, however, please note the following considerations. The SH68-C68-S shielded cable contains 34 twisted pairs of conductors. To maximize the digital I/O available on the NI 78xxR, some of the DIO lines are twisted with power or ground and some DIO lines are twisted with other DIO lines.

  • Page 43: Rtsi Trigger Bus

    Each local bus is 13 lines wide. All of these lines connect to the FPGA on the NI PXI-781xR/783xR. © National Instruments Corporation 2-21 R Series Intelligent DAQ User Manual...
  • Page 44 Chapter 2 Hardware Overview of the NI 78xxR The PXI local bus right lines on the NI PXI-781xR/783xR are PXI/LBR<0..12>. The PXI local bus left lines on the NI PXI-781xR/783xR are PXI/LBLSTAR<0..12>. The NI PXI-781xR/783xR can configure each PXI local bus line either as an input or an output signal.

  • Page 45: Switch Settings (Ni 781Xr/783Xr Only)

    SW1 is in the OFF position. To prevent a VI stored in flash memory from loading to the FPGA at power up, move SW1 to the ON position, as shown in Figure 2-17. Note SW2 and SW3 are not connected. © National Instruments Corporation 2-23 R Series Intelligent DAQ User Manual...
  • Page 46 Chapter 2 Hardware Overview of the NI 78xxR SW1, SW2, SW3 Figure 2-13. Switch Location on the NI PCI-781 x R R Series Intelligent DAQ User Manual 2-24 ni.com...
  • Page 47 N I P X I- 7 8 1 1 R e c o n fi g u ra b le I/ O Figure 2-14. Switch Location on the NI PXI-781 x R © National Instruments Corporation 2-25 R Series Intelligent DAQ User Manual...
  • Page 48 Chapter 2 Hardware Overview of the NI 78xxR SW1, SW2, SW3 Figure 2-15. Switch Location on the NI PCI-783 x R R Series Intelligent DAQ User Manual 2-26 ni.com...
  • Page 49 Complete the following steps to prevent a VI stored in flash memory from loading to the FPGA: Power off and unplug the PXI/CompactPCI chassis or PCI computer. Remove the NI 781xR/783xR from the PXI/CompactPCI chassis or PCI computer. © National Instruments Corporation 2-27 R Series Intelligent DAQ User Manual...

  • Page 50: +5 V Power Source

    Chapter 2 Hardware Overview of the NI 78xxR Move SW1 to the ON position, as shown in Figure 2-17b. Reinsert the NI 781xR/783xR into the PXI/CompactPCI chassis or PCI computer. Refer to the Installing the Hardware section of the Getting Started with R Series Intelligent DAQ document for installation instructions.

  • Page 51: Device Fuse Replacement (Ni 784Xr/785Xr Only)

    Power down and unplug the computer or PXI chassis. Remove the PCI device from the expansion slot on the computer, or the PXI device from the PXI slot in the PXI chassis. © National Instruments Corporation 2-29 R Series Intelligent DAQ User Manual...
  • Page 52 Chapter 2 Hardware Overview of the NI 78xxR Replace the broken fuse while referring to Figure 2-18 for the fuse locations. 1 Littelfuse Part Number 0453 004 (NI Part Number 766247-01) Figure 2-18. NI 784 x R/785 x R Replacement Fuse Location Reinstall the PCI or PXI device into the computer or PXI chassis.

  • Page 53: Field Wiring Considerations (Ni 783Xr/784Xr/785Xr Only)

    Refer to the NI Developer Zone tutorial, Field Wiring and Noise Considerations for Analog Signals, at for more information. ni.com/zone © National Instruments Corporation 2-31 R Series Intelligent DAQ User Manual...

  • Page 54: Calibration (Ni 783 X R/784 X R/785 X R Only)

    NI provides software to perform an internal calibration. This internal calibration process, which generally takes less than two minutes, is the preferred method of assuring accuracy in your © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 55: External Calibration

    Note The NI 78xxR Calibration Utility does not support NI 781xR devices. If you have NI-RIO installed, you can find the internal calibration utility at Start»All Programs»National Instruments»NI-RIO»Calibrate 78xxR Device. Device is the NI PXI-783xR/784xR/785xR or NI PCI-783xR device. Immediately after internal calibration, the only significant residual calibration error is gain error due to time and temperature drift of the onboard voltage reference.
  • Page 56 To externally calibrate your device, use an external reference several times more accurate than the device itself. For more information on externally calibrating your NI 783xR/784xR/785xR device, refer to the NI 783xR Calibration Procedure for NI-RIO, found on ni.com/manuals © National Instruments Corporation R Series Intelligent DAQ User Manual...

  • Page 57: Appendix A Connecting I/O Signals

    Figure A-2 shows the I/O connector pin assignments and locations for NI PCI-7830R/7831R/7833R and the NI PXI-7830R/7831R/7833R/ 7841R/7842R/7851R/7852R/7853R/7854R. Note The NI PXI-7830R and NI PCI-7830R do not have Connector 2 (RDIO). © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 58 Appendix A Connecting I/O Signals 68 34 DIO39 DIO38 DIO37 67 33 DIO36 TERMINAL 68 TERMINAL 35 66 32 DIO35 DIO34 65 31 DIO32 DIO33 TERMINAL 34 TERMINAL 1 64 30 DIO30 DIO31 DIO29 63 29 DIO28 DIO27 62 28 61 27 DIO26 60 26...
  • Page 59 DGND DIO1 DGND DIO1 DGND DIO0 DGND DIO0 1 No Connect on the NI 7830R Figure A-2. NI 783 x R/784 x R/785 x R Connector Pin Assignments and Locations © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 60 Appendix A Connecting I/O Signals To access the signals on the I/O connectors, you must connect a cable from the I/O connector to a signal accessory. Plug the small VHDCI connector end of the cable into the appropriate I/O connector and connect the other end of the cable to the appropriate signal accessory.
  • Page 61 NI 784xR, and NI 785xR) DIO<0..39> Connector <1..2> (NI 783xR, NI 784xR, and NI 785xR) AI = Analog Input AO = Analog Output DIO = Digital Input/Output DO = Digital Output © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 62 Appendix A Connecting I/O Signals Connecting to 5B and SSR Analog Signal Conditioning (NI 783 x R/784 x R/785 x R Only) NI provides cables that allow you to connect signals from the NI 783xR/784xR/785xR directly to 5B backplanes for analog signal conditioning and SSR backplanes for digital signal conditioning.
  • Page 63 SSR backplanes for digital signal conditioning. This cable has a 68-pin male VHDCI connector on one end that plugs into the NI 78xxR RDIO connectors. The other end of this cable provides two 50-pin female headers. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 64 Appendix A Connecting I/O Signals You can plug each of these 50-pin headers directly into an 8-, 16-, 24-, or 32-channel SSR backplane for digital signal conditioning. One of the 50-pin headers contains DIO<0..23> from the NI 78xxR RDIO connector. These lines correspond to Slots <0..23>...
  • Page 65 SCB-68 to the with the SHC68-68-RMIO (for Connector 0 on the NI 783xR/784xR/785xR) or SHC68-68-RDIO (Connector <0..3> on the NI 781xR and Connector <1..2> on the NI 783xR/784xR/785xR) shielded cables. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 66 Technical Support and Professional Services Visit the following sections of the award-winning National Instruments Web site at for technical support and professional services: ni.com • Support—Technical support resources at include ni.com/support the following: – Self-Help Technical Resources—For answers and solutions,...
  • Page 67 Appendix C Technical Support and Professional Services Declaration of Conformity (DoC)—A DoC is our claim of • compliance with the Council of the European Communities using the manufacturer’s declaration of conformity. This system affords the user protection for electromagnetic compatibility (EMC) and product safety.
  • Page 68 Greater than or equal to. < Less than. ≤ Less than or equal to. – Negative of, or minus. Ω Ohms. Per. Percent. ± Plus or minus. Positive of, or plus. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 69 Application-Specific Integrated Circuit—A proprietary semiconductor component designed and manufactured to perform a set of specific functions. bipolar A signal range that includes both positive and negative values (for example, –5 to +5 V). R Series Intelligent DAQ User Manual © National Instruments Corporation...
  • Page 70 Decibel—The unit for expressing a logarithmic measure of the ratio of two signal levels: dB = 20log10 V1/V2, for signals in volts. Direct current. DGND Digital ground signal. DIFF Differential mode. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 71 A configuration that is downloaded to the FPGA and that determines the functionality of the hardware. glitch An unwanted signal excursion of short duration that is usually unavoidable. Hour. Hardware-in-the-loop. Hertz. R Series Intelligent DAQ User Manual © National Instruments Corporation...
  • Page 72 Multiplexer—A switching device with multiple inputs that sequentially connects each of its inputs to its output, typically at high speeds, in order to measure several signals with a single analog input channel. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 73 (2) A digital port, consisting of four or eight lines of digital input and/or output. Parts per million. Pull-up. Pulse-width modulation. PCI eXtensions for Instrumentation—An open specification that builds off the CompactPCI specification by adding instrumentation-specific features. R Series Intelligent DAQ User Manual © National Instruments Corporation...
  • Page 74 The voltage rate of change as a function of time. The maximum slew rate of an amplifier is often a key specification to its performance. Slew rate limitations are first seen as distortion at higher signal frequencies. © National Instruments Corporation R Series Intelligent DAQ User Manual...
  • Page 75 Volts, input high. Volts, input low. Volts, output high. Volts, output low. Volts, root mean square. waveform Multiple voltage readings taken at a specific sampling rate. R Series Intelligent DAQ User Manual © National Instruments Corporation...

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