National Instruments NI 785xR инструкция обслуживания

Intelligent DAQ NI R Series Intellig ent DAQ User Manual NI 781xR, 783xR, NI 784xR, and NI 785xR D evices R Series Intelligent DAQ User Manual June 2008 370489F-01[...]

Support Worldwide Technical Support and Product Info rmation ni.com National Instruments Corporate Headquarters 11500 North Mopac Expressway Aust in, Texas 78759-3504 USA Tel: 512 683 0100 Worldwide Offices Australia 1800 300 800, Austria 43 662 457990-0, Belgium 32 (0) 2 757 0020, Brazil 55 11 3262 3599, Canada 800 433 3488, China 86 21 5050 9800,[...]

Important Information Warranty The NI 7811R/ 7813R/7830R/ 7831R/7833R/ 7841R/7842 R/7851R/78 52R/7853R/78 54R is warrant ed against defects i n materials and workmanshi p for a period of on e year from the da te of shipment, as evidenced by receip ts or other do cumentation. National Instr uments will, at its option, repair or replace equipment tha[...]

Compliance Compliance with FCC/Canada Radio Frequency Interference Regulations Determining FCC Class The Federal Communications Commission (FCC) has rules to protect wireless co mmunications from inte rference. The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrial-commercial locations onl y) [...]

© National Instruments Corporation v R Series Intelligent DAQ User Manual Contents About This Manual Conventions ............ .............. .............. .............. ........... ............... .............. .............. ....... v ii Related Documentation ............ .............. .............. .............. .............. ............[...]

Contents R Series Intelligent DAQ User Manual vi ni.com Types of Signal Sources ........ .............. ............ .............. .............. .............. .............. ...... 2-8 Floating Signal Sources ... .............. .............. .............. .............. ........... ............ 2-8 Ground-Referenced Signal So ur ces ..........[...]

© National Instruments Co rporation vii R Series Inte lligent DAQ User Manual About This Manual This manual describes the electrical and mechanical aspects of the National Instruments 781 x R/ 783 x R/784 x R/785 x R devices and contains information about programming and using the devices. Conventions The following con v entions appear in this man[...]

About This Manual R Series Intelligent DAQ User Manual viii ni.com monospace T ext in this font denotes text or ch aracters that you should ent er from the keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper na mes of disk dri ves, paths, directories, programs, subprograms, su broutines, d ev[...]

About This Manual © National Instruments Corporation ix R Series Intelligent DAQ User Manual information about using the FPGA Module to create VIs that run on the NI 78 xx R device. – LabVIEW FPGA Module Release and Upgrade Notes —Cont ains information about inst alling the LabVIEW FPGA Module, describes new features, and pr ovides upgrade inf[...]

About This Manual R Series Intelligent DAQ User Manual x ni.com Additional Resources The following documents contain information you migh t find helpful: • NI Dev eloper Zone tutorial, Field Wiring and Noise Considerati ons for Analog Signals , at ni.com/zone • PICMG CompactPCI 2.0 R3.0 • PXI Hardware Specifica tion Revision 2.1 • PXI Softw[...]

© National Instruments Corporation 1-1 R Series Intelligent DAQ User Manual 1 Introduction This chapter describes the NI 781 x R/783 x R/784 x R/785 x R, the concept of the Reconfigurable I/O (RIO) device, optional software and equipment for using the NI 78 xx R, and safety information about the NI 78 xx R. About the Reconfigurable I/O Device Tabl[...]

Chapter 1 Introduction R Series Intelligent DAQ User Manual 1-2 ni.com instrument (VI) to the FPGA. Using the FPGA Module, you can graphically design the timing an d functionality of the R Series device. If you only have LabVIEW but not the FPGA Module, you cannot create new FPGA VIs, b ut you can create VIs that run on W indow s or a LabVIEW Real-[...]

Chapter 1 Introduction © National Instruments Corporation 1-3 R Series Intelligent DAQ User Manual PXI-specific features are implemen ted on the J2 connector of the CompactPCI b us. T able 1-2 lists th e J2 pins used by the NI PXI-78 xx R. The NI 78 xx R is compatible with any CompactPCI chassis with a sub-bus that does not driv e these lines. Eve[...]

Chapter 1 Introduction R Series Intelligent DAQ User Manual 1-4 ni.com Flexible Functionality Flexible function ality allows the N I 78 xx R to match indi vidual application requirements and t o mimic th e functionality of fixed I/ O devices. For example, you can configure an R Series device in one application for three 32-bit quadrature encoders a[...]

Chapter 1 Introduction © National Instruments Corporation 1-5 R Series Intelligent DAQ User Manual Reconfigurable I/O Architecture Figure 1-1 shows an FPGA connected to fixed I/O resources and a bus interface. The fix ed I/O resources include A/D con verters (ADCs), D/A con verters (D A Cs), and digital I/O lines. Figure 1-1. High-Level FPGA F unc[...]

Chapter 1 Introduction R Series Intelligent DAQ User Manual 1-6 ni.com The FPGA does not retain the VI when the R Series de vice is po wered off, so you must reload the VI each time you po wer on the de vice. Y ou can load the VI from onboard flash memory or from software o ver the b us interf ace. One adv antage to using flash memory is that the V[...]

Chapter 1 Introduction © National Instruments Corporation 1-7 R Series Intelligent DAQ User Manual Note If you use the R Series device without the FPGA Module, you can use the RIO Device Setup utility , av ailable by selecting Start»All Programs»National Instruments» NI-RIO»RIO Devi ce Setup to download precomplied FPGA VI s to the flash memor[...]

Chapter 1 Introduction R Series Intelligent DAQ User Manual 1-8 ni.com Cables and Accessories National Instruments offers a v ariety of product s you can use with R Series devices, including cables, connect or blocks, and other accessories, as shown in Table 1-3. Refer to Appendix A , Connecting I/O Sign als , for more informat ion about using thes[...]

Chapter 1 Introduction © National Instruments Corporation 1-9 R Series Intelligent DAQ User Manual Custom Cabling NI offers a variety of cables for connecting signals to the N I 78 xx R. If you need to develop a custom cable, a nont erminated shiel ded cable is available from NI. The SHC68-NT-S connects to the NI 78 xx R VHDCI connectors on one en[...]

Chapter 1 Introduction R Series Intelligent DAQ User Manual 1-10 ni.com • Pollution Degree 3 means that conductiv e pollution occurs, or dry , nonconductiv e pollution occurs that becomes conductive due to condensation. Y ou must insulat e signal connectio ns for the m aximum voltage for w hich the device is rated. Do not e xceed the maximum rati[...]

Chapter 1 Introduction © National Instruments Corporation 1-11 R Series Intelligent DAQ User Manual • Measurement Category III is for measurements performed in the building installation at the distribution le vel. This cate gory refers to measurements on hard-wir ed equipment such as equipment in f ixed installations, distribution boards, and ci[...]

© National Instruments Corporation 2-1 R Series Intelligent DAQ User Manual 2 Hardware Over view of the NI 78 xx R This chapter presents an overview of the hardware functi ons and I/O connectors on the NI 78 xx R. Figure 2-1 shows a block diagram for the NI 781 x R. Figure 2-2 shows a block diagram for the NI 783 0R. Figure 2-3 shows a block diagr[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-2 ni.com Figure 2-2. NI 7830R Block Diagram RTSI/PXI Triggers PXI Local Bus (NI PXI-7830R only) Connector 0 (MIO) Connector 1 (DIO) Input Mode Mux AISENSE AIGND Calibration Mux V oltage Reference T emperature Sensor Calibration DAC s 2 x4 Channels 16-Bit DAC Digit[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-3 R Series Intelligent DAQ User Manual Figure 2-3. NI 783 1R/7833R/784 x R/785 x R Block Diagram NI 7811R Over view The NI 7811R has 1 60 bidirectional DIO lines and a V irtex-II XC2V100 0 FPGA. NI 7813R Over view The NI 7813R has 1 60 bidirectional DIO lines and a[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-4 ni.com NI 7831R/7833R Over view The NI 7831R/7833R each have eight independent, 16-bit AI channels; eight independent, 16-bi t AO channels; 96 bidirecti onal DIO lines that you can configure individually for input or ou tput; and a V irtex-II XC2V3000 FPGA. NI 7[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-5 R Series Intelligent DAQ User Manual Input Modes The NI 783 x R/784 x R/785 x R input mode is software configurab le. The input channels support three input mo des—differential (D IFF), referenced single ended (RSE), and nonreferenced single ended (NRSE). The s[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-6 ni.com Connecting Analog Input Signals The AI signals for the NI 783 x R/78 4 x R/785 x R are AI<0.. n >+, AI<0.. n >– , AIGND, and AISENSE. For the NI 7830R, n =4. For the NI 7831R/7833R/7 84 x R/785 x R, n =8. The AI<0.. n >+ and AI<0.. [...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-7 R Series Intelligent DAQ User Manual Connection of AI signals to the NI 783 x R/784 x R/78 5 x R depends on the input mode of the AI channels you are using and the typ e of input signal source. W ith dif ferent input modes, you can use the instrumentation amplifi[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-8 ni.com T ypes of Signal Sources When configuring t he input channels and making signal connections, you must first det ermine whether the signal sources are fl oating or ground referenced. The following sections describ e these two signal types. Floating Signal [...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-9 R Series Intelligent DAQ User Manual Figure 2-5 summarizes the recommended in put mode for both types of signal sources. Figure 2-5. Summary of Analog Input Connections + – + – V 1 AI< i > AISENSE AIGND< i > + – + – V 1 AI< i > AISENSE A[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-10 ni.com Differential Connection Consid erations (DIFF Input Mode) In DIFF input mode, the NI 783 x R/784 x R/785 x R measures the difference between the positive and negative input s. DIFF input mode is ideal for measuring ground-referenced signals from other de[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-11 R Series Intelligent DAQ User Manual Differential Connections for Ground-Referenced Signal Sources Figure 2-6 shows how to co nnect a gr ound-referenced signal source to a channel on the NI 783 x R/784 x R/785 x R configur ed in DIFF input mode. Figure 2-6. Diff[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-12 ni.com Differential Connections for Nonreferenced or Floating Signal Sources Figure 2-7 shows how to connect a floa ting signal source to a channel on the NI 783 x R/784 x R/785 x R configured in DI FF input mode. Figure 2-7. Differential Input Connections for [...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-13 R Series Intelligent DAQ User Manual line to AIGND, connect it to AIGND th rough a resistor that is about 100 times the equiv alent source impeda nce. The resistor puts the signal path nearly in balance. About the same amount of noise couples onto both connectio[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-14 ni.com Use DIFF input connections for greater signal integrity for any input signal that does not meet the preceding conditions. Y ou can configure the NI 783 x R/784 x R/785 x R channels in softw are for RSE or NRSE input modes. Use the RSE i nput mode for flo[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-15 R Series Intelligent DAQ User Manual Single-Ended Connections for Grounded Signal Sources (NRSE Input Mode) To measure a grounded signal source with a single-ended input mode, you must configure the NI 783 x R/784 x R/785 x R in the NRSE input mode. Then connect[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-16 ni.com Common-Mode Signal Re jection Considerations Figure 2-6 and Figure 2-9 show connectio ns for signal sources that are already referenced to some ground point with respect to the NI 783 x R/784 x R/785 x R. In these cases, the inst rumentation amplifi er c[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-17 R Series Intelligent DAQ User Manual Connecting Analog Output Signals The AO signals are AO <0.. n > and AOGND. AO < 0 . . n > are the A O channels. A O GND is the ground reference signal for the A O channels. Figure 2-10 shows ho w to make A O conne[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-18 ni.com NI 7830R has one RMIO and one RDIO connector for a total of 56 DIO lines. The NI 7831R/7833R/78 4 x R/785 x R has one RMIO and two RDIO connectors for a total of 96 DIO lines. Refer to Figure A -1, NI 781x R Co nnector Pin Assignments and Locat ions , fo[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-19 R Series Intelligent DAQ User Manual Figure 2-11. Example Digital I/O Connections Figure 2-11 shows DIO<0..3> configured for digital input and DIO<4..7> configured for digital ou tput. Digital input appli cations include recei ving TTL, L VTTL, CMOS,[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-20 ni.com The SHC68-68-RDIO was designed specifically for R Series de vices and is the NI-recommended cable for digital applications. If you are using the SH68-C68-S cable, howe ver , p lease no te the following considerations. The SH68-C68-S shield ed cable conta[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-21 R Series Intelligent DAQ User Manual R TSI T rigger Bus The NI 78 xx R can send and receive triggers through the RTSI trigger bus. The RTSI bus provides ei ght shared trigger lines that connect to all the devices on the bus. In PXI, the trigge r lines are shared[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-22 ni.com The PXI local bus right lines on the NI PXI-781 x R/783 x R are PXI/LBR<0..12> . The PXI l ocal bus left lines on the NI PXI-781 x R /783 x R are PXI/LBLSTAR<0..12>. The NI PXI-781 x R/783 x R can configure each PXI lo cal b us line either as[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-23 R Series Intelligent DAQ User Manual Figure 2-12. PXI Star T rigger Connections in a PXI Chassis Refer to the PXI Hardware Specifica tion Revision 2.1 and PXI Sof tware Specification Revision 2.1 at www.pxisa.org for mor e information about PXI triggers. Switch [...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-24 ni.com Figure 2-13. Switch Location on the NI PCI-781 x R SW1, SW2, SW3[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-25 R Series Intelligent DAQ User Manual Figure 2-14. Switch Location on the NI PXI-781 x R NI P XI- 7811 R Reconfigu rab le I/O CONNECTOR 2 (DIO) CONNECTOR 3 (DIO) SW1, SW2, SW3[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-26 ni.com Figure 2-15. Switch Location on the NI PCI-783 x R SW1, SW2, SW3[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-27 R Series Intelligent DAQ User Manual Figure 2-16. Switch Location on the NI PXI-783 x R Figure 2-17. Switch Settings Complete the following steps to pr e vent a VI stored in flash memory from loading to the FPGA: 1. Power of f and unplug the PXI/CompactPCI chass[...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-28 ni.com 3. Move SW1 to the ON position, as shown in Figure 2-17b. 4. Reinsert the NI 781 x R/783 x R into the PXI/CompactPCI chassis or PCI computer . Refer to the Installing the Hardware section of the Getting Started wi th R Series In telligent DA Q document f[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-29 R Series Intelligent DAQ User Manual (NI 784 x R/785 x R Devices) All NI 784 x R/78 5 x R devices ha v e a user-replac eable socketed fuse to protect the supply from ov ercurrent conditions. When an ov ercurrent condit ion occurs, check your cabling to the +5 V [...]

Chapter 2 Hardware Overv iew of the NI 78x x R R Series Intelligent DAQ User Manual 2-30 ni.com 3. Replace the broken fuse while ref erring to Figure 2-18 fo r the fuse locations. Figure 2-18. NI 784 x R/785 x R Replacement Fuse Location 4. Reinstall the PCI or PXI de vice into the computer or PXI chassis. 1 Littelf us e P a rt N u m b er 045 3 004[...]

Chapter 2 Hardware O verview of the NI 78x x R © National Instruments Corporation 2-31 R Series Intelligent DAQ User Manual Field Wiring Considerations (NI 783 x R/784 x R/785 x RO n l y ) Environmental noise can se riously affect the meas urement accuracy of the device if you do not take proper care when running signal wires bet ween signal sourc[...]

© National Instruments Corporation 3-1 R Series Intelligent DAQ User Manual 3 Calibration (NI 783 x R/784 x R/785 x RO n l y ) Calibration is the process of determin ing and/or adjusting the accuracy of an instrument to m inimize measurement and output voltage errors. On the NI 783 x R/784 x R/785 x R, onboard calibratio n DACs (CalDACs) correct t[...]

Chapter 3 Calibration ( N I 783x R/784x R/785x R Only) R Series Intelligent DAQ User Manual 3-2 ni.com application. Internal calibration mini mizes the effects of any offset and gain drifts, partic ularly those due t o changes in temperature. During the internal calibration process, the AI an d AO channels are compared to the NI 783 x R/784 x R/785[...]

Chapter 3 Calibration (NI 7 83x R/784x R/785x R Only) © National Instruments Corporation 3-3 R Series Intelligent DAQ User Manual T o externally calibrate your de vice, use an e xternal reference se veral times more accurate than the de vice itself. For more information on e xternally calibrating your NI 783 x R/784 x R/785 x R device, refer to th[...]

© National Instruments Corporation A-1 R Series Intelligent DAQ User Manual A Connecting I/O Signals This appendix describes how to make input and output signal connections to the NI 78 xx R I/O connectors. Figure A-1 sho ws the I/O connector pin assignments and locations for NI PCI-7811R/7813R and NI PXI-7811R/7813R. Figure A-2 sho ws the I/O con[...]

Appendix A Connecting I/O Signals R Series Intelligent DAQ User Manual A-2 ni.com Figure A-1. NI 781 x R Connector Pin Assignments and Locations DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND +5V +5V DIO28 DIO31 DIO33 DIO35 DIO37 DIO39 DIO0 DIO2 DIO3 DIO5 DIO6 DIO7 D[...]

Appendix A Connecting I/O Signals © National Instruments Corporation A-3 R Series Intelligent DAQ User Manual Figure A-2. NI 783 x R/784 x R/785 x R Connector Pin Assignments and Locations +5V DGND DGND DGND DGND DGND DGND DGND DGND DIO8 DIO10 DIO12 DIO14 AOG N D 7 AOG N D 6 AOG N D 5 AOG N D 4 AOG N D 3 AOG N D 2 AOG N D 1 AOG N D 0 No Connect AI[...]

Appendix A Connecting I/O Signals R Series Intelligent DAQ User Manual A-4 ni.com T o access the signals on the I/O connect ors, you must connect a cable from the I/O connector to a signal acces sory . 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 [...]

Appendix A Connecting I/O Signals © National Instruments Corporation A-5 R Series Intelligent DAQ User Manual Caution Connections that exceed any of the maximum ratings of input or output si gnals on the NI 78 xx R can damage the NI 78 xx R and the computer . Maximum input ratings for each signal are in the Protection column of T able A-2. NI is n[...]

Appendix A Connecting I/O Signals R Series Intelligent DAQ User Manual A-6 ni.com Connecting to 5B and SSR Analog Signal Conditioning (NI 783 x R/784 x R/785 x R Only) NI provides cables that allo w yo u to connect signals from the NI 783 x R/784 x R/785 x R directly to 5B backplanes for analog signal conditioning and SSR backplanes for digital sig[...]

Appendix A Connecting I/O Signals © National Instruments Corporation A-7 R Series Intelligent DAQ User Manual Figure A-3 shows the connector pinouts when us ing the NSC68-262650 cable. Figure A-3. Connector Pinouts when Using NSC68-262650 Cable Connecting to SSR Digital Signal Conditioning NI provides cables that allo w you to connect signals from[...]

Appendix A Connecting I/O Signals R Series Intelligent DAQ User Manual A-8 ni.com Y ou can plug each of these 50-pin head ers directly into an 8-, 16-, 24-, or 32-channel SSR backplane for dig ital signal conditioning. One of th e 50-pin headers contains DIO<0..23> from the NI 78 xx R RDIO connector . These lines correspond to Sl ots <0..2[...]

© National Instruments Corporation B-1 R Series Intelligent DAQ User Manual B Using the SCB-68 Shielded Connector Block This appendix describes how to connect input and output signals to the NI 78 xx R with the SCB-68 shielded connector block. The SCB-68 has 68 screw terminals for I/O signal connections. T o use the SCB-68 with the NI 78 xx R, you[...]

© National Instruments Corporation C-1 R Series Intelligent DAQ User Manual C T echnical Support and Professional Ser vices Visit the following sections of the award-winning National Instruments Web site at ni.com for technical support and professional services: • Support —T echnical support resources at ni.com/support include the following: ?[...]

Appendix C T echnical Support and Professional Services R Series Intelligent DAQ User Manual C-2 ni.com • Declaration of Conformit y (DoC) —A DoC is our claim of compliance with the C ouncil of th e European Communities using the manufacturer’ s declaration of conformity . This system affords the user protection f or electromagne tic compatib[...]

© National Instruments Corporation G-1 R Series Intelligent DAQ User Manual Glossar y Symbol Pref ix V alu e pp i c o 1 0 –1 2 nn a n o 1 0 –9 µ micro 10 –6 m milli 10 –3 k kilo 10 3 Mm e g a 1 0 6 Gg i g a 1 0 9 Numbers/Symbols ° Degrees. > Greater than. ≥ Greater than or equal to. < Less than. ≤ Less than or equal to. – Neg[...]

Glossary R Series Intelligent DAQ User Manual G-2 © National Instruments Corporation Square root of. +5V +5 VDC source signal. A A Amperes. A/D Analog-to-digital . A C Alternating curren t. ADC Analog-to-digital con verter—An elect ronic de vice, often an integrated circuit, that con verts an an alog voltage to a digital number . AI Analog input[...]

Glossary © National Instruments Corporation G-3 R Series Intelligent DAQ User Manual C CC e l s i u s . CalD A C Calibration D A C. CH Channel—Pin or wire lead to wh ich you apply or from which you read the analog or digital signal. Anal og signals can be single-ended or differential. For digital signals, you group channels to form ports. Ports [...]

Glossary R Series Intelligent DAQ User Manual G-4 © National Instruments Corporation DIO Digital input /output. DIO< i > Digital input/ou tput channel signal. DMA Direct memory access—A method by which data can be transferred to/from computer memory from/to a device or memory on the bus while the processor does something else. DMA is th e [...]

Glossary © National Instruments Corporation G-5 R Series Intelligent DAQ User Manual I I/O Input/output—The transfer of data to/from a computer sy stem in volving communications channels, operator interface de vices, and/or data acquisition and control interfaces. INL Relati ve accurac y . L LabVIEW Laboratory V irtual Instrument Engin eering W [...]

Glossary R Series Intelligent DAQ User Manual G-6 © National Instruments Corporation N noise An undes irable electrical signal—Nois e comes from external sources such as the A C power line, motors, generators, transformers, f luorescent lights, CR T displays, computers, electrical st orms, welders, r adio transmitt ers, and internal sources such[...]

Glossary © National Instruments Corporation G-7 R Series Intelligent DAQ User Manual R RAM Random-access memory—The generic term for the read/write memory that is used in computers. RAM allows bits and bytes to be written to it as well as read from. V arious types of RAM are DRAM, EDO RAM, SRAM, and VRAM. resolution The smallest signal increment[...]

Glossary R Series Intelligent DAQ User Manual G-8 © National Instruments Corporation T THD T otal harmonic distortion—The rati o of the total rms signal due to harmonic distortion to the overall rms signal, in decibel or a percentage. thermocouple A temperature se nsor created by joining tw o dissim ilar metals. The junction produces a small vol[...]