National Instruments E Series Field Wiring Considerations

Chapter 4 Signal Connections

DAQCard E Series User Manual 4-44

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National Instruments Corporation

Field Wiring Considerations

Environmental noise can seriously affect the accuracy of

measurements made with your DAQCard if you do not take proper care

when running signal wires between signal sources and the DAQCard.

The following recommendations apply mainly to analog input signal

routing to the DAQCard, although they also apply to signal routing in

general.

You can minimize noise pickup and maximize measurement accuracy

by taking the following precautions:

• Use differential analog input connections to reject common-mode

noise.

• Use individually shielded, twisted-pair wires to connect analog

input signals to the DAQCard. With this type of wire, the signals

attached to the CH+ and CH- inputs are twisted together and then

covered with a shield. You then connect this shield only at one

point to the signal source ground. This kind of connection is

required for signals traveling through areas with large magnetic

fields or high electromagnetic interference.

• Route signals to the DAQCard carefully. Keep cabling away from

noise sources. The most common noise source in a computer data

acquisition system is the video monitor. Separate the monitor from

the analog signals as much as possible.

The following recommendations apply for all signal connections to

your DAQCard:

• Separate DAQCard signal lines from high-current or high-voltage

lines. These lines are capable of inducing currents in or voltages

on the DAQCard signal lines if they run in parallel paths at a close

distance. To reduce the magnetic coupling between lines, separate

them by a reasonable distance if they run in parallel, or run the

lines at right angles to each other.

• Do not run signal lines through conduits that also contain power

lines.

• Protect signal lines from magnetic fields caused by electric

motors, welding equipment, breakers, or transformers by running

them through special metal conduits.

Contents

Main Page Important Information This document was created with FrameMaker 4.0.4 WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS Trademarks Page Chapter 4 Signal Connections Page Page Figures Tables About This Manual Organization of This Manual Conventions Used in This Manual National Instruments Documentation Related Documentation Customer Communication Introduction About the DAQCard E Series What You Need to Get Started LabVIEW and LabWindows/CVI Application Software Software Programming Choices NI-DAQ Driver Software Register-Level Programming Optional Equipment Custom Cabling Unpacking Installation and Configuration Installation Configuration Page National Instruments Corporation 3-1 DAQCard E Series User Manual Hardware Overview DAQ - STC This document was created with FrameMaker 4.0.4 I/O Connector Analog Input Input Mode Input Polarity and Input Range Page Page Considerations for Selecting Input Ranges Dither Chapter 3 Hardware Overview National Instruments Corporation 3-7 DAQCard E Series User Manual d. Dither enabled; average of 50 acquisitions c. Dither enabled; no averaging Dither Figure 3-3. Page Analog Trigger Page Page Digital I/O Timing Signal Routing Programmable Function Inputs DAQCard Clocks Many functions performed by the DAQCard E Series cards require a Signal Connections I/O Connector DAQCard E Series User Manual 4-2 Figure 4-1. I/O Connector Pin Assignment for the DAQCard-AI-16E-4 and DAQCard-AI-16XE-50 National Instruments Corporation 4-3 DAQCard E Series User Manual Table 4-1. I/O Connector Signal Descriptions DAQCard E Series User Manual 4-4 Table 4-1. I/O Connector Signal Descriptions (Continued) National Instruments Corporation 4-5 DAQCard E Series User Manual Table 4-2 shows the I/O signal summary for the DAQCard-AI-16E-4. I/O Signal Summary, DAQCard-AI-16E-4 Table 4-2. I/O Signal Summary, DAQCard-AI-16E-4 (Continued) Table 4-2. National Instruments Corporation 4-7 DAQCard E Series User Manual Table 4-2. I/O Signal Summary, DAQCard-AI-16E-4 (Continued) DAQCard E Series User Manual 4-8 Table 4-3 shows the I/O signal summary for the DAQCard-AI-16XE-50. I/O Signal Summary, DAQCard-AI-16XE-50 Table 4-3. Table 4-3. I/O Signal Summary, DAQCard-AI-16XE-50 (Continued) Analog Input Signal Connections Page Types of Signal Sources Input Configurations Ground-Referenced Signal Sources Floating Signal Sources Figure 4-3 summarizes the recommended input configuration for both types of signal sources. Summary of Analog Input Connections Figure 4-3. Differential Connection Considerations (DIFF Input Configuration) National Instruments Corporation 4-15 DAQCard E Series User Manual Differential Connections for Ground-Referenced Signal Sources Differential Input Connections for Ground-Referenced Signals Figure 4-4. in Figure 4-4. Differential Connections for Nonreferenced or Floating Signal Sources Page Single-Ended Connection Considerations Single-Ended Connections for Floating Signal Sources (RSE Configuration) Single-Ended Connections for Grounded Signal Sources (NRSE Configuration) Common-Mode Signal Rejection Considerations Digital I/O Signal Connections Power Connections Timing Connections Page Programmable Function Input Connections Data Acquisition Timing Connections SCANCLK Signal EXTSTROBE* Signal TRIG1 Signal Page TRIG2 Signal STARTSCAN Signal Page Page CONVERT* Signal AIGATE Signal SISOURCE Signal UISOURCE Signal General-Purpose Timing Signal Connections GPCTR0_SOURCE Signal GPCTR0_GATE Signal GPCTR0_OUT Signal GPCTR0_UP_DOWN Signal GPCTR1_SOURCE Signal GPCTR1_GATE Signal GPCTR1_OUT Signal GPCTR1_UP_DOWN Signal FREQ_OUT Signal Field Wiring Considerations Calibration Loading Calibration Constants Self-Calibration External Calibration Other Considerations Specifications A DAQCard-AI-16E-4 Analog Input Input Characteristics Page Transfer Characteristics Dynamic Characteristics Amplifier Characteristics Stability Digital I/O Timing I/O Triggers Analog Trigger Power Requirement (from PCMCIA I/O channel) Digital Trigger Physical Environment DAQCard-AI-16XE-50 Analog Input Input Characteristics Transfer Characteristics Amplifier Characteristics Dynamic Characteristics Stability Digital I/O Timing I/O Page B Appendix B Optional Cable Connector Descriptions DAQCard E Series User Manual B-2 Figure B-1. 68-Pin AI Connector Pin Assignments Appendix B Optional Cable Connector Descriptions 50-Pin AI Connector Pin Assignments Figure B-2. PC Card Questions and Answers C Configuration Operation Resources Page Resource Conflicts Common Questions D General Information Installation and Configuration Analog Input and Output Timing and Digital I/O Page Page Power-Management Modes E Page Customer Communication FTP Support Electronic Services F Bulletin Board Support Fax and Telephone Support Telephone Fax FaxBack Support E-Mail Support (currently U.S. only) Technical Support Form DAQCard E Series Hardware and Software Configuration Form Other Products National Instruments Products Documentation Comment Form Glossary Symbols A C B D E F H G Page P S R T V U W B A Numbers C D E F G I H L P O N Page Q S R Page T