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NI 4551/4552 User Manual

1. Chapter 4 Signal Connections Table 4 2 Analog 1 0 Signal Summary Signal Rise Type and Time Signal Name Direction Impedance Protection Source Sink ns Bias Lr lt 0 3 gt 1MQ 42 4 V on 100 pA in parallel 42 4 V off with 50 pF to AIGND lt 0 3 gt 1MQ 42 4 V on m 100 pA in parallel 42 4 V off with 50 pF to AIGND AIGND AI DACOOUT AO 22 Q to Short circuit to 16 7 mA at DACOOUT DACOOUT 10 4 55 to ground AOGND DACOOUT AO 22 Q to Short circuit to 16 7 mA at DACOOUT DACOOUT 10 V 4 55 kQ to ground AOGND DACIOUT AO 22 Q to Short circuit to 16 7 mA at DACIOUT DACIOUT 10 4 55 to ground AOGND DACIOUT AO 22 Q to Short circuit to 16 7 mA at DACIOUT DACIOUT 10 4 55 to ground AOGND AOGND AO DGND DIO 5 079 Short circuit to 0 5A ground Analog Input DIO Digital Input Output AO Analog Output DO Digital Output 400 V 400 V guaranteed by design but not tested or certified to operate beyond 42 4 V NI 4551 4552 User Manual 4 4 National Instruments Corporation Digital 1 0 Connector Signal Descriptions Chapter 4 Signal Connections Figure 4 2 shows the digital pin connections for the NI 4551 4552 DIOO DIO2 DIOS DIO5 DIO6 DIO8 DIO9 01011 01012 01014 01015 01022 01020 01017 01018 5 45V 45V DIO23
2. 1 MQ in parallel with 50 pF and each to AIGND Frequency response Gain 0 10 20 30 40 dB 0 1 dB 0 through 95 kHz 204 8 kS s DC coupling 20 10 50 60 1 dB 0 95 kHz 0 1 dB 0 20 kHz 3 dB bandwidth 0 493 f Input software selectable AC 3 dB cutoff frequency 3 4 Hz Common mode range Gain 20 dB Both and should remain within 12 V of AIGND Gain 0 dB sees Both and should remain within 42 4 V of AIGND Overvoltage protection 42 4 V powered on or off 400 V guaranteed by design but not tested or certified to operate beyond 42 4 V Inputs protected ACHO ACH1 ACH2 ACH3 Common mode rejection ratio figs cet 90 dB Gain 20 dB 60 dB Gain 0 dB National Instruments Corporation A 3 NI 4551 4552 User Manual Appendix A Specifications Noise dB Full Scale 65 0 70 0 75 0 80 0 95 0 1 000 10 000 100 000 1 000 000 Sample Rate S s NI 4551 4552 User Manual Figure A 1 Idle Channel Noise Typical Input noise spectral density 8 nV JHz achievable only at Gain 50 dB or 60 dB
3. 99 esse Ny uonoes o1 sng suluezzeyy Boyeuy Woudaa l d 1 se 66u p puer S ERE sebeueyy 1 seBeueyy pelea 1 011002 a a nueces ges 1 ova ree ee pecs ee pees coe see E 1 i JOD Jonuoo ova 16Beue N enas Dav pon SEN FEE 1 indino uonenuenv jesyjo ure i jesyojureo ueg 1 1 oq ov WO 1ndNI i 1 1 1 Y Y Y i exnw exnw jt w EC ou ME Po ia 8p 02 8 0 oa ov I L 1 1 1 1 L 1 1 1 1 I 1 v v v ZXNN zxnn E wo suo ayonan i 8 0Z 9P 0 oq ov I 1 1 1 4 44 pes WO LNdNI 8p 02 8 0 oQ ov o 5 a o 29 c lt v it 4 aia Y v Y KG oxnw OXniN D ure 4 oz ap o oa ow 11 Analog Bus Figure 3 2 Analog Function Block Diagram NI 4551 4552 User Manual 3 3 National Instruments Corporation Chapter 3 Hardware Overview Analog Input The analog input section of each NI 4
4. 3 5 Table 3 2 Actual Range and Measurement Precision of 3 7 Table 4 1 Analog I O Connector Pin Assignment esee 4 3 Table 4 2 Analog I O Signal Summary 4 4 Table 4 3 Digital I O Connector Pin Assignment 4 6 Table 4 4 Digital I O Signal Summary eee 4 6 NI 4551 4552 User Manual Viii National Instruments Corporation About This Manual This manual describes the electrical and mechanical aspects of the NI 4551 and NI 4552 instruments and contains information concerning their operation Unless otherwise noted the text applies to both instruments The NI 4551 and NI 4552 are high performance high accuracy analog input output I O instruments for the PCI bus These instruments also support digital I O DIO functions counter timer functions and external trigger functions Organization of This Manual The NI 4551 4552 User Manual is organized as follows National Instruments Corporation Chapter 1 Introduction describes the NI 4551 and NI 4552 instruments lists what you need to get started explains how to unpack your instruments and describes the optional software and optional equipment Chapter 2 Installation and Configuration explains how to install and configure your NI 4551 4552 instrument Chapter 3 Hardware Overview presents an overview of the
5. eessesesseeeeeeer enne ener nennen nee 4 10 Digital Power Connections oec lees e Ee e eR e beret 4 12 Field Wiring Considerations eene enne enne 4 12 Chapter 5 Calibration 1 amp E e eene enne enne 5 1 ente PU e EU HR RE ee tenda 5 2 External Calibration eet Re PU e UTAH peine Reus 5 2 Traceable Recalibration eese eene nennen nennen S 5 3 Chapter 6 Theory of Analog Operation Analog Inp t CIICUTEV ves ie ne titi be ertet ta del eh e Hep e 6 1 Input Coupling ise Ee eg eid eeu emn 6 2 Cahbratiofi tte e eec ptu acie eedem 6 2 Antialias Filtering e esent 6 2 grs bom 6 7 NOISE ovt iND Mna even 6 8 Analog Output oe teer e teet SR PUR AE ORARE 6 9 Anti Image Filtering enne nennen nennen 6 9 The DAC itd aee espe re e e ette 6 11 Cahbr tion e Regu ee a 6 12 6 12 NI 4551 4552 User Manual vi National Instruments Corporation Appendix A Specifications Appendix B Pin Connections Appendix C Contents Customer Communication Glossary Index Figures Figure 3 1 Figure 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Figure 4 5 Figure 6 1 Figure 6 2 Figur
6. see Delta sigma 64 times oversampling Sample fate Sannier etes 1 25 51 2 kS s in increments of 47 684 uS s Frequency 100 ppm National Instruments Corporation A 5 NI 4551 4552 User Manual Appendix A Specifications Output signal range software selectable Attenuation Linear Log Full Scale Range 1 0 dB 10 0 10 20 1 00 100 40 dB 0 100 V FIFO buffer size esee 256 samples Data transfers seen DMA programmed I O Interrupt Transfer Characteristics Offset residual DC 5 mV max any gain Gain amplitude 0 1 dB fpu 1 kHz Voltage Output Characteristics Output 1 22 Q between and DACXxOUT 4 55 to AOGND Frequency response 0 2 dB 0 to 23 kHz 51 2 kS s 3 dB bandwidth sss 0 492 f Output coupling eee DC Short circuit protection us Yes and may be shorted together indefinitely Outputs DACOOUT XDACIOUT Idle channel noise 91 dB f DC to 23 kHz measurement bandwidth NI 4551 4552 User Manual A 6 National Instruments Corporation Appendix A Specific
7. E Mail Address Phone Fax Mail to Technical Publications Faxt0 Technical Publications National Instruments Corporation National Instruments Corporation 6504 Bridge Point Parkway 512 794 5678 Austin Texas 78730 5039 Glossary Prefix Meanings Value p pico 10 2 n nano 10 9 u micro 10 6 m milli 10 3 k kilo 10 M mega 106 G giga 10 t tera 1022 Numbers Symbols percent positive of or plus negative of minus per degree Q ohm 5 5 VDC source signal A A amperes AC alternating current AC coupled allowing the transmission of AC signals while blocking DC signals National Instruments Corporation G 1 NI 4551 4552 User Manual Glossary ACH A D ADC ADC resolution AIGND alias amplification amplitude flatness antialiasing filter anti imaging filter AOGND ASIC asynchronous NI 4551 4552 User Manual analog input channel signal analog to digital analog to digital converter an electronic device often an integrated circuit that converts an analog voltage to a digital number the size of the discrete steps in the ADC s input to output transfer function therefore the smallest voltage difference an ADC can discriminate with a single measurement analog input ground signal a false lower frequency component that appears in sampled data acquired at too low a sampling rate a
8. 57 AB 58 59 n 60 61 DS 62 63 6 64 65 66 67 Co AB 68 DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND 5 V DGND DGND DGND DGND DGND DGND DGND DGND DGND DGND Figure B 1 68 Pin Digital Connector for Any Digital Accessory B 2 National Instruments Corporation Customer Communication For your convenience this appendix contains forms to help you gather the information necessary to help us solve your technical problems and a form you can use to comment on the product documentation When you contact us we need the information on the Technical Support Form and the configuration form if your manual contains one about your system configuration to answer your questions as quickly as possible National Instruments has technical assistance through electronic fax and telephone systems to quickly provide the information you need Our electronic services include a bulletin board service an FTP site a fax on demand system and e mail support If you have a hardware or software problem first try the electronic support systems If the information available on these systems does not answer your questions we offer fax and telephone support through our technica
9. M AU 100 Gain 0 dB Gain 20 dB AOGND Gain 40 dB Gain ee dB NV Figure 4 4 Analog Output Channel Block Diagram The analog output stage is differential and balanced Each output signal consists of a plus connection a minus connection and a ground AOGND connection The actual output signal is the difference between the plus and minus connections The pair is balanced meaning that if the impedance from each of the pair to AOGND is the same or infinite then the voltage at the plus and minus terminals is equal but opposite so that their difference is the desired signal and their sum or average is zero If impedance from each of the pair to AOGND is not the same the connection is unbalanced but the difference between the plus and minus terminals is still equal to the desired signal If the minus side is grounded the plus voltage is equal to the signal Conversely if the plus side is grounded the minus voltage is equal to the negative of the signal In all cases the difference is equal to the signal Connection of analog output signals from your NI 4551 instrument depends on the configuration of the devices receiving the signals For most signals you use a DIFF configuration and simply connect DACxOUT where is the NI4551 channel to the signal and DACxOUT to the signal ground or signal minus as appropriate When driving some floating devices however you may sometimes find it helpfu
10. National Instruments Corporation 6 5 NI 4551 4552 User Manual Chapter 6 Theory of Analog Operation sample rate is illustrated in Figure 6 3 For frequencies not near multiples of the oversampling rate the rejection is better than 85 dB Alias Rejection dB 0 00 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 Sample Rate 1 kS s Oversample 128 kHz Frequency 10 kS s 100 kS s 1 MS s 1 28 MHz 12 8 MHz 128 MHz NI 4551 4552 User Manual Figure 6 3 Alias Rejection at the Oversample Rate There is a form of aliasing that no filter can prevent When a waveform exceeds the voltage range of the ADC it is said to be clipped or overranged When clipping occurs the ADC assumes the closest value in its digital range to the actual value of the signal which is always either 32 768 or 32 767 Clipping nearly always results in an abrupt change in the slope of the signal and causes the corrupted digital data to have high frequency energy This energy is spread throughout the frequency spectrum and because the clipping happens after the antialiasing filters the energy is aliased back into the baseband The remedy for this problem is simple do not allow the signal to exceed the nominal input range Figure 6 4 shows the spectra of 10 5 Vms and 10 0 3 0 kHz sine waves digitized at
11. Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently National Instruments Products NI 4551 4552 instrument NI 4551 4552 instrument serial number Base memory address of the NI 4551 4552 instrument Programming choice and version NI DAQ LabVIEW or other Other boards in system Base I O address of other boards DMA channels of other boards Interrupt level of other boards Other Products Computer make and model Microprocessor Clock frequency or speed Type of video board installed Operating system version Operating system mode Programming language Programming language version Other boards in system Base I O address of other boards DMA channels of other boards Interrupt level of other boards Documentation Comment Form National Instruments encourages you to comment on the documentation supplied with our products This information helps us provide quality products to meet your needs Title NI 4551 4552 User Manual Edition Date April 1998 Part Number 321934A 01 Please comment on the completeness clarity and organization of the manual If you find errors in the manual please record the page numbers and describe the errors Thank you for your help Name Title Company Address
12. 12 to 6 13 analog power connections 4 10 analog trigger 3 7 to 3 11 above high level analog triggering mode figure 3 9 below low level analog triggering mode figure 3 9 high hysteresis analog triggering mode figure 3 10 inside region analog triggering mode figure 3 10 low hysteresis analog triggering mode figure 3 10 specifications A 8 antialias filtering 6 3 to 6 7 alias rejection at oversample rate figure 6 6 clipped or overranged 6 6 to 6 7 comparison of clipped signal to proper signal figure 6 7 frequency response 6 5 input frequency response figure 6 4 input frequency response near cutoff figure 6 5 Nyquist frequency example 6 3 NI 4551 4552 User Manual l 2 anti image filtering signal spectra in DAC figure 6 11 theory of operation 6 10 to 6 11 AOGND signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 analog output signal connections 4 8 to 4 9 B bipolar input 3 4 bipolar output 3 6 block diagrams analog function 3 3 digital function 3 2 bulletin board support C 1 bus interface specifications A 9 C cables See also I O connectors custom cabling 1 5 field wiring considerations 4 12 to 4 13 optional equipment 1 4 calibration 5 1 to 5 3 external calibration 5 2 to 5 3 loading calibration constants 5 1 to 5 2 onboard calibration reference specifications A 5 self calibration 5 2 specifications A 10 theory of operation ana
13. 19 by 1 84 cm 4 19 by 12 28 by 0 73 in not including connectors Digital I O connector 50 pin VHDIC female type Analog I O connector 68 pin VHDIC female type Environment Operating temperature 0 C to 40 C Storage temperature range 25 C to 85 C Relative humidity sssss 10 to 95 no condensation Calibration Calibration 1 year NI 4551 4552 User Manual A 10 National Instruments Corporation Pin Connections This appendix describes the pin connections on the optional 68 pin digital accessories for the NI 4551 and NI 4552 instruments National Instruments Corporation B 1 NI 4551 4552 User Manual Appendix B Pin Connections NI 4551 4552 User Manual DIOO DIO1 DIO2 DIOS DIO4 DIO5 DIO6 DIO7 DIO8 DIO9 DIO10 DIO11 DIO12 DIO13 01014 01015 01016 01017 DIO18 DIO19 DIO20 01021 01022 5 DIO23 01024 01025 01026 01027 01028 01029 01030 01031 EXT_TRIG 35 36 37 38 39 40 41 To 42 43 i 44 a 8 45 Po 46 47 a AB 48 49 x 50 N 51 52 53 54 N 55 N N 56 N
14. 34 6 0 5 sample periods The NI 4551 analog outputs have calibration adjustments Onboard CalDACSs remove the offset and gain errors for each channel For complete calibration instructions refer to Chapter 5 Calibration The two channel DAC chip on the NI 4551 goes into mute mode if the chip receives at least 4 096 consecutive zero values on both channels at once In mute mode the outputs clamp to ground and the noise floor drops from about 92 dB below full scale to about 120 dB below full scale Upon receiving any nonzero data the DAC instantly reverts to normal mode Mute mode quiets the background noise to extremely low levels when no 6 12 National Instruments Corporation Chapter 6 Theory of Analog Operation waveforms are being generated Mute mode has a slightly different offset from the normal offset when zeros are being sent As a result the DAC has one offset for the first 4 096 zero samples and another offset in mute mode for as long as zeros are sent This difference is usually less than 1 mV National Instruments Corporation 6 13 NI 4551 4552 User Manual Specifications This appendix lists the specifications of the NI 4551 4552 These specifications are typical at 25 C unless otherwise noted The system must be allowed to warmup for 15 minutes to achieve the rated accuracy Note Be sure to keep the cover on your computer to maintain forced air cooling Analog Input Channel Characteristics Number of
15. 48 0 49 0 50 Frequency Sample Rate fs Figure 6 2 Input Frequency Response Near the Cutoff Because the ADC samples at 128 times the data rate frequency components above 64 times the data rate can alias The digital filter rejects most of the frequency range over which aliasing can occur However the filter can do nothing about components that lie close to 128 times the data rate 256 times the data rate and so on because it cannot distinguish these components from components in the baseband 0 Hz to the Nyquist frequency If for instance the sample rate is 200 kS s and a signal component lies within 100 kHz of 25 6 MHz 128 x 200 kHz this signal is aliased into the passband region of the digital filter and is not attenuated The purpose of the analog filter is to remove these higher frequency components near multiples of the oversampling rate before they get to the sampler and the digital filter While the frequency response of the digital filter scales in proportion to the sample rate the frequency response of the analog filter remains fixed The filter response is optimized to produce good high frequency alias rejection while having a flat in band frequency response Because this filter is third order its roll off is rather slow This means that although the filter has good alias rejection for high sample rates it does not reject as well at lower sample rates The alias rejection near 128 times the sample rate versus the
16. AIGND 8 42 AIGND NC 9 43 NC AIGND 10 44 AIGND NC 11 45 NC AIGND 12 46 AIGND NC 13 47 NC AIGNDt 14 48 AIGND NC 15 49 NC AIGND 16 50 AIGND NC 17 51 NC AIGND 18 52 AIGND NC 19 53 NC AIGND 20 54 AIGND NC 21 55 NC AIGND 22 56 AIGND NC 23 57 NC AIGND 24 58 AIGND DACOOUT 25 59 DACOOUT AOGND 26 60 AOGND DAC1OUT 27 61 DAC10UT AOGND 28 62 AOGND NC 29 63 NC AOGND 30 64 AOGND NC 31 65 NC AOGND 32 66 AOGNDt 5V 133 67 45V DGND 4 68 DGND Not available on NI 4551 Not available on NI 4552 TThese AIGND and AOGND pins are not connected in the SHC68 C68 A1 cable Figure 4 1 Analog Pin Connections 4 2 National Instruments Corporation Chapter 4 Signal Connections Table 4 1 Analog 1 0 Connector Pin Assignment Signal Name Reference Direction Description ACH lt 0 3 gt AIGND Input Analog Input Channel 0 through 3 The NI 4551 uses ACH lt 0 1 gt and the NI 4552 uses ACH lt 0 3 gt lt 0 3 gt AIGND Input Analog Input Channel 0 through 3 The NI 4551 uses lt 0 1 gt and the NI 4552 uses ACH lt 0 3 gt AIGND Analog Input Ground These pins are the reference point for single ended measurements in SE configuration and the bias current return point for differential measurements All three ground references AIGND AOGND and DGND are connected together on your NI 4551 4552 instrumen
17. Communication at the end of this manual National Instruments Corporation Xi NI 4551 4552 User Manual Introduction This chapter describes the NI 4551 and NI 4552 instruments lists what you need to get started explains how to unpack your instruments and describes the optional software and optional equipment Thank you for buying the NI 4551 4552 dynamic signal analyzer instrument for PCI The NI 4551 4552 are high performance high accuracy analog I O instruments for the PCI bus These instruments are members of the PCI DSA instrument family and are specifically designed for demanding dynamic signal acquisition applications The NI 4551 has two channels of 16 bit simultaneously sampled input at 204 8 kS s and two channels of 16 bit simultaneously updated output at 51 2 kS s The NI 4552 has four channels of 16 bit simultaneously sampled analog input at 204 8 kS s Information on analog output applies only to the NI 4551 but information on analog input applies to both the NI 4551 and the NI 4552 Both the analog input and the analog output circuitry have oversampling delta sigma modulating converters Delta sigma converters are inherently linear provide built in brick wall antialiasing imaging filters and have specifications that exceed other conventional technology for this application with regard to THD SNR and amplitude flatness You can use these high quality specifications and features to acquire or generate signals with h
18. DIO25 DIO26 DIO28 DIO29 DIO31 EXT TRIG 26 27 28 29 30 31 32 A 33 34 35 36 Dv 37 38 a A 39 oa 40 e 41 N 42 43 44 45 N prt 46 N N 47 N 48 N K 49 m 50 DGND DIO1 DGND DIO4 DGND DIO7 DGND DIO10 DGND DIO13 DGND 01021 DGND DIO19 DGND DIO16 DGND 5 DGND 01024 DGND DIO27 DGND DIO30 DGND Figure 4 2 Digital Pin Connections Refer to Appendix B Pin Connections for the digital pin connections of the 68 pin connector National Instruments Corporation 4 5 NI 4551 4552 User Manual Chapter 4 Signal Connections Table 4 3 Digital 1 0 Connector Pin Assignment Signal Name Reference Direction Description DIO lt 0 31 gt DGND Input or Digital I O channels 0 through 31 Output DGND Digital Ground This pin supplies the reference for the digital signals at the I O connector as well as the 5 VDC supply 5 DGND Output 5 VDC Source These pins are fused for up to 1 A of 5 V supply The fuse is self resetting EXT_TRIG DGND Input or External trigger This pin is used as the trigger to start an Output acquisition and waveform generation Table 4 4 Digital
19. Dynamic Characteristics Alias free bandwidth DC to 0 464 f Alias rejection cere tree eere 80 dB 0 536 f lt fi lt 63 464 f Spurious free dynamic range 95 dB 80 90 dB for fin lt 20 kHz or signal lt 1 Vy IMD size 100 dB CCIF 14 kHz 15 kHz Crosstalk channel separation 100 dB DC to 100 kHz A 4 National Instruments Corporation Appendix A Specifications Phase linearity eee 1 Gain 0 dB 2 Gain lt 0 dB Interchannel 1 Gain 2 0 dB 2 Gain 0 dB same configuration all input channels Interchannel gain mismatch X 0 1 dB for all gains same configuration for all input channels Signal delay item eis 42 sample periods any sample rate time from when signal enters analog input to when digital data is available Onboard Calibration Reference Analog Output DC level oreet 5 000 V 22 5 mV Temperature coefficient 5 max Long term stability 15 ppm 1 000 h NI 4551 only Channel Characteristics Number of channels 2 simultaneously updated Output configuration Balanced differential Resolution eere 16 bits Type of DAC
20. In two s complement mode digital data values read from the analog input channel are either positive or negative Considerations for Selecting Input Ranges The input range you select depends on the expected range of the incoming signal A large input range can accommodate a large signal variation but reduces the voltage resolution Choosing a smaller input range improves the voltage resolution but can result in the input signal going out of range For best results match the input range as closely as possible to the expected range of the input signal If you exceed the rated input voltages you can damage the computer and the connected equipment AN Caution If you do not choose the input range appropriately an input signal can be clipped and can introduce large errors that are easily identified in the frequency spectrum The NI 4551 4552 is equipped with overrange detection circuits in both the analog and digital sections of each input channel These circuits determine if an input signal has exceeded the National Instruments Corporation 3 5 NI 4551 4552 User Manual Chapter 3 Hardware Overview Analog Output selected input voltage Chapter 6 Theory of Analog Operation provides a more in depth explanation of how overranges can occur Output Mode The analog output section of the NI 4551 instrument is software configurable You can select different analog output configurations through application software designed to contr
21. J Caution not under any circumstances connect these 5 V power pins directly to analog ground digital ground or to any other voltage source on the NI 4551 4552 or any other device Doing so can damage the NI 4551 4552 and the computer National Instruments is not liable for damages resulting from such a connection Field Wiring Considerations NI 4551 4552 User Manual Environmental noise can seriously influence the accuracy of measurements made with your NI 4551 4552 if you do not take proper care when running signal wires between signal sources and the instrument The following recommendations apply mainly to analog input signal routing to the instrument although they also apply to signal routing in general Minimize noise pickup and maximize measurement accuracy by taking the following precautions e Use differential analog input connections to reject common mode noise e Use individually shielded twisted pair wires to connect analog input signals to the instrument With this type of wire the signals attached to the ACHx and 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 e Route signals to the instrument carefully Keep cabling away from noise sources The most common noise source in a PCI D
22. NI 4551 4552 instruments from any other PCI DSA or National Instruments device that has the RTSI bus feature You can connect the devices through the RTSI bus cable An external digital trigger can also trigger multiple devices simultaneously by distributing that trigger through the RTSI bus You can also select the polarity of the external digital trigger The seven RTSI trigger lines on the RTSI bus provide a flexible interconnection scheme for any NI 4551 4552 instrument sharing the RTSI bus These bidirectional lines can drive the digital trigger onto the RTSI bus and can receive this signal The NI 4551 4552 instruments contain 32 lines of digital I O for general purpose use through the 50 pin connector You can individually software configure each line for either input or output Note At system power on and reset the hardware sets the DIO lines to high impedance Table 4 4 shows that there is a 100 pull down resistor These pull down resistors set the DIO pin to a logic low when the output is in a high impedance state Take careful consideration of the power on state of the system to prevent any damage to external equipment Timing Signal Routing The TIO ASIC provides a flexible interface for connecting timing signals to other instruments or to external circuitry Your NI 4551 4552 instrument uses the RTSI bus to connect timing signals between instruments and uses the DIO pins on the I O connector to connect the instrument to
23. address listed below Remember to include your name address and phone number so we can contact you with solutions and suggestions support natinst com Telephone and Fax Support National Instruments has branch offices all over the world Use the list below to find the technical support number for your country If there is no National Instruments office in your country contact the source from which you purchased your software to obtain support Country Australia Austria Belgium Brazil Canada Ontario Canada Qu bec Denmark Finland France Germany Hong Kong Israel Italy Japan Korea Mexico Netherlands Norway Singapore Spain Sweden Switzerland Taiwan United Kingdom United States NI 4551 4552 User Manual Telephone 03 9879 5166 0662 45 79 90 0 02 757 00 20 011 288 3336 905 785 0085 514 694 8521 45 76 26 00 09 725 725 11 01 48 14 24 24 089 741 31 30 2645 3186 03 6120092 02 413091 03 5472 2970 02 596 7456 5 520 2635 0348 433466 32 84 84 00 2265886 9 640 0085 08 730 49 70 056 200 51 51 02 377 1200 01635 523545 512 795 8248 C 2 Fax 03 9879 6277 0662 45 79 90 19 02 757 03 11 011 288 8528 905 785 0086 514 694 4399 45 76 26 02 09 725 725 55 01 48 14 24 14 089 714 60 35 2686 8505 03 6120095 02 41309215 03 5472 2977 02 596 7455 5 520 3282 0348 430673 32 84 86 00 2265887 9 640 0533 08 730 43 70 056 200 51 55 02 737 4644 01635 523154 512 794 5678 National I
24. and high level features e Software documentation You may have both application software and NI DAQ software documentation National Instruments application software includes ComponentWorks LabVIEW LabWindows CVI Measure and VirtualBench After you set up your hardware system use either your application software documentation or the NI DAQ documentation to help you write your application If you have a large complicated system it is worthwhile to look through the software documentation before you configure your hardware e Accessory installation guides or manuals If you are using accessory products read the terminal block and cable assembly installation guides They explain how to physically connect the relevant pieces of the system Consult these guides when you are making your connections Related Documentation The following documents contain information you may find helpful e BNC 2140 User Manual e National Instruments Application Note 025 Field Wiring and Noise Considerations for Analog Signals e PCI Local Bus Specification Revision 2 0 Customer Communication National Instruments wants to receive your comments on our products and manuals We are interested in the applications you develop with our products and we want to help if you have problems with them To make it easy for you to contact us this manual contains comment and configuration forms for you to complete These forms are in Appendix C Customer
25. apes 3 4 Inp t Coupling nete 3 4 Input Polarity and Input Range nennen 3 4 Considerations for Selecting Input Ranges eee 3 5 Analog Outputs conte agi iat awit iat Bee ee ees 3 6 Output eei 3 6 Output Polarity and Output Range sse 3 6 MAB DEL c eeweees 3 7 RTSUTDPSeISuzicmesdusunstekp eheeieigemgepesIeesigtieie 3 11 Digital Oy iere eere et e eic ete ge d pee 3 11 Timing Signal Routing onnee e reete NEE Erene re NRR ENU Ra ins 3 11 National Instruments Corporation V NI 4551 4552 User Manual Contents Selecting Sample Update Clock Frequency eene 3 12 NI 4551 4552 LED rette Hen EPIIT IPOIEOI 3 13 Chapter 4 Signal Connections VO Connectors ite rper EEEE eto ede bau eee 4 1 Analog I O Connector Signal Descriptions esee 4 2 Digital I O Connector Signal Descriptions 4 5 Analog Input Signal 4 6 Types ot Signal SOULCES cre eret nee tp re e rete ees 4 8 Floating Signal Sources sse nennen 4 8 Ground Referenced Signal Sources esee 4 8 Analog Output Signal Connections essent 4 8 Analog Power Connections eic e sca eit e o ete P ee E eie e 4 10 Digital I O Signal Connections
26. are directly affected by converter DNL The NI 4551 4552 analog inputs typically have a dynamic range of more than 90 dB The dynamic range of a circuit is the ratio of the magnitudes of the largest signal the circuit can carry and the residual noise in the absence of a signal In a 16 bit system the largest signal is taken to be a full scale sine wave that peaks at the codes 432 767 and 32 768 Such a sine wave has an rms magnitude of 32 768 1 414 23 170 475 least significant bits LSBs A grounded channel of the NI 4551 4552 has a noise level of about 0 65 LSB rms this amount fluctuates The ratio of 23 170 475 0 65 is about 35647 or 91 0 dB the dynamic range Several factors can degrade the noise performance of the inputs First noise can be picked up from nearby electronics The NI 4551 4552 works best when it is kept as far away as possible from other plug in devices power supplies disk drives and computer monitors Cabling is also critical Make sure to use well shielded coaxial or balanced cables for all connections and route the cables away from sources of interference such as computer monitors switching power supplies and fluorescent lights Finally choose the sample rate carefully Take advantage of the antialias filtering that removes signals beyond the band of interest Computer monitor noise for example typically occurs at frequencies between 15 and 50 KHz If the signal of interest is restricted to below 1
27. channels Input configuration Resolution re Type of ADU ierosin neninn Sample rates snieter 2 NI 4551 or 4 NI 4552 simultaneously sampled True differential 16 bits Delta sigma 128 times oversampling 5 kS s to 204 8 kS s in increments of 190 735 uS s Frequency 100 ppm Input signal ranges Software selectable Gain Linear Log Full Scale Range Peak 0 1 20 dB 42 4 V 0 316 10 dB 31 6 V 1 0 dB 10 0 3 16 10 dB 3 16 V National Instruments Corporation A 1 NI 4551 4552 User Manual Appendix A Specifications Gain Linear Log Full Scale Range Peak 10 20 dB 1 00 V 31 6 30 dB 0 316 V 100 40 dB 0 100 V 316 50 dB 0 0316 V 1000 60 dB 0 0100 V FIFO buffer size 256 samples Data transfers Transfer Characteristics DMA programmed I O interrupt INL relative 2 LSB DNE teet eie eee 0 5 LSB typ 1 LSB max no missing codes Offset residual DC Gain Max Offset 20 dB 30 mV 10 dB 10 mV 0 dB 3 mV 10 dB 1 mV 20 dB 300 uV 30 40 50 60 dB 100 Gain amplitude accuracy 0 1 dB f 1 kHz NI 4551 4552 User Manual A 2 National Instruments Corporation Appendix A Specifications Amplifier Characteristics Input
28. connect the analog I O to the shielded cable through a single 68 pin connector The digital I O connector for the NI 4551 4552 has 50 pins that you can connect to generic 68 pin terminal blocks through the SHC50 68 shielded cable You can connect the digital I O signals to the shielded cable through a single 50 pin connector 1 0 Connectors Table 4 1 describes the pin assignments for the 68 pin analog I O connector Table 4 3 describes the 50 pin digital connector on the NI 4551 4552 instruments A signal description follows the connector pinouts AN Caution Connections that exceed any of the maximum ratings of input or output signals on the NI 4551 4552 instruments can damage the NI 4551 4552 instrument the computer and accessories Maximum input ratings for each signal are given in the Protection column of Table 4 2 and 4 4 National Instruments is not liable for any damages resulting from such signal connections National Instruments Corporation 4 1 NI 4551 4552 User Manual Chapter 4 Signal Connections Analog 1 0 Connector Signal Descriptions NI 4551 4552 User Manual Figure 4 1 shows the analog pin connections for the NI 4551 4552 ACHO 1 35 AIGND 2 36 AIGND ACH1 3 37 ACH1 AIGND 4 38 AIGND ACH2 5 39 ACH AIGNDt 6 40 AIGND ACH3 7 41
29. digital I O signal connections 4 10 digital I O signal summary table 4 6 DIFF configuration 4 7 DIFF input mode 3 4 DIFF output mode 3 6 digital function block diagram 3 2 digital I O high impedance state note 3 11 overview 3 11 pin connections figure 4 5 signal connections 4 10 to 4 11 signal descriptions pin assignments table 4 6 pin connections figure 4 5 signal summary table 4 6 specifications A 7 to A 8 digital power connections 4 12 digital trigger specifications A 9 DIO lt 0 31 gt signal digital I O pin assignments table 4 6 digital I O signal connections 4 10 to 4 11 digital I O signal summary table 4 6 direct digital synthesis DDS technology 3 12 documentation conventions used in manual x National Instruments documentation xi organization of manual ix x related documentation xi dynamic characteristic specifications analog input A 4 to A 5 analog output A 7 NI 4551 4552 User Manual Index E EEPROM storage of calibration constants 5 1 electronic support services C 1 to C 2 e mail support C 2 environment specifications A 10 environmental noise avoiding 4 12 to 4 13 6 8 equipment optional 1 4 EXT_TRIG signal digital I O pin assignments table 4 6 digital I O signal summary table 4 6 F fax and telephone support numbers C 2 Fax on Demand support C 2 field wiring considerations 4 12 to 4 13 floating signal sources 4 8 FTP support C 1 fuse self
30. directly using external clock signals You can only generate sample and update rates using the DDS clock circuitry NI 4551 4552 User Manual The DDS clock signal and the synchronization start signal digital trigger are transmitted to other PCI DSA instruments via the RTSI bus The NI 4551 4552 can also receive these signals to synchronize the acquisition or waveform generation with other devices In a multidevice system a master device would drive the clock and synchronization signal to other slave or receiving devices Selecting a sample rate that is less than two times the frequency of a band of interest seems to indicate that the board is functioning improperly By undersampling the signal you could receive what appears to be a DC signal This situation is due to the sharp antialiasing filters that remove frequency components above the sampling frequency If you have a situation where this occurs increase the sample rate until it meets the requirements of the Shannon Sampling Theorem For more information on the filters and aliasing refer to Chapter 6 Theory of Analog Operation Unlike other converter technologies delta sigma converters must be run continuously and at a minimum clock rate To operate within guaranteed specifications the ADCs should operate at a minimum sample rate of 5 0 kS s and the DACs should operate at a minimum update rate of 3 12 National Instruments Corporation Chapter 3 Hardware Overview 1 25 kS
31. external circuitry These connections enable the NI 4551 4552 instrument to both control and be controlled by other devices and circuits National Instruments Corporation 3 11 NI 4551 4552 User Manual Chapter 3 Hardware Overview Selecting Sample Update Clock Frequency The two analog input channels of the NI 4551 and the four inputs of the NI 4552 are simultaneously sampled at any software programmable rate from 5 0 kS s to 204 8 kS s in 190 7 uS s increments worst case The instruments use direct digital synthesis DDS technology so that you can choose the correct sample rate required for your application All the input channels acquire data at the same rate One input channel cannot acquire data at a different rate than another input channel The two analog output channels of the NI 4551 are updated simultaneously at any software programmable rate from 1 25 kS s to 51 2 kS s in 47 684 uS s increments worst case The input sample rate and output update rate on the NI 4551 are synchronized and derived from the same DDS clock The input and output clocks may differ from each other by a factor of 2 1 2 4 8 128 while still maintaining their synchronization as long as the lower bounds for update and sample rate are maintained AII the output channels update data at the same rate One output channel cannot update data at a different rate than another output channel r Note You cannot generate the sample rate and update rate
32. generated based on the input trigger In this case you must be aware of the inherent delays of the finite impulse response FIR filters internal to the delta sigma converters and you must account for the delays The delay through the input converter is 42 sample periods while the delay through the output converter is 34 6 0 5 sample periods During repetitive sampling of a waveform you may observe jitter due to the uncertainty of where a trigger level falls compared to the actual digitized data Although this trigger jitter is never greater than one sample period it can seem quite bad when the sample rate is only twice the bandwidth of interest This jitter has no effect on the processing of the data and you can decrease this jitter by oversampling There are five analog level triggering modes available as shown in Figures 3 3 through 3 7 You can set lowValue and highValue independently in the software 3 8 National Instruments Corporation Chapter 3 Hardware Overview In below low level triggering mode shown in Figure 3 3 the trigger is generated when the signal value is less than lowValue HighValue is unused lowValue Trigger oo Figure 3 3 Below Low Level Triggering Mode In above high level triggering mode the trigger is generated when the signal value is greater than highValue LowValue is unused highValue Trigger ERE DERE Figure 3 4 Above High Level Triggerin
33. hardware functions on your NI 4551 4552 instrument Chapter 4 Signal Connections describes how to make input and output connections to your NI 4551 4552 instrument via the analog I O and digital I O connectors of the instrument Chapter 5 Calibration discusses the calibration procedures for your NI 4551 4552 instrument Chapter 6 Theory of Analog Operation contains a functional overview and explains the operation of each analog functional unit making up the NI 4551 4552 Appendix A Specifications lists the specifications of the NI 4551 4552 Appendix B Pin Connections describes the pin connections on the optional 68 pin digital accessories for the NI 4551 4552 instruments Appendix C Customer Communication contains forms you can use to request help from National Instruments or to comment on our products and manuals ix NI 4551 4552 User Manual About This Manual Glossary contains an alphabetical list and description of terms used in this manual including abbreviations acronyms metric prefixes mnemonics and symbols e ndex contains an alphabetical list of key terms and topics in this manual including the page where you can find each one Conventions Used in This Manual lt gt bold italic DSA italic SE NI 4551 4552 User Manual The following conventions are used in this manual Angle brackets enclose the name of a key on the keyboard for example shift Angl
34. high resolution analog signals to high rate 1 bit digital data whereas in the DAC the delta sigma modulator is digital circuitry that converts high resolution digital data to high rate 1 bit digital data As in the ADC the modulator frequency shapes the quantization noise so that almost all of its energy is above the signal frequency refer to The ADC earlier in this chapter The digital 1 bit data is then sent directly to a simple 1 bit DAC This DAC can have only one of two analog values and therefore is inherently perfectly linear The output of the DAC however has a large amount of quantization noise at higher frequencies and as described in the section Anti Image Filtering some images still remain near multiples of eight times the sample rate Two analog filters eliminate the quantization noise and the images The first is a fifth order switched capacitor filter in which the cutoff frequency scales with the sample frequency and is approximately 0 52 times the sample frequency This filter has a four pole Butterworth response and an extra pole at about 1 04 times the sample frequency The second filter is a continuous time second order Butterworth filter in which the cutoff frequency at 80 kHz does not scale with the sample frequency This filter mainly removes high frequency images from the 64 times oversampled switched capacitor filter These filters cause a delay between the input digital data and the output analog data of
35. noise above the frequency range of interest This out of band noise is typically removed by digital filters a plug in data acquisition board card or pad that can contain multiple channels and conversion devices Plug in boards PCMCIA cards and devices such as the DAQPad 1200 which connects to your computer parallel port are all examples of DAQ devices SCXI modules are distinct from devices with the exception of the SCXI 1200 which is a hybrid digital ground signal differential mode an analog input consisting of two terminals both of which are isolated from computer ground whose difference is measured a way you can configure your device to read signals in which you do not need to connect either input to a fixed reference such as the earth or a building ground See port a TTL level signal having two discrete levels a high and a low level digital input output 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 the fastest method of transferring data to from computer memory G 6 National Instruments Corporation DNL down counter drivers dynamic range E EEPROM EMC encoder EPROM event expansion ROM EXT_TRIG external trigger National Instruments Corporation G 7 Glossary differential nonlinearity a measure in least significant bit of the worst case deviat
36. range conditional retrieval conversion device NI 4551 4552 User Manual Celsius calibration DAC pin or wire lead to which you apply or from which you read the analog or digital signal Analog signals can be single ended or differential For digital signals you group channels to form ports Ports usually consist of either four or eight digital channels a condition for starting or stopping clocks clipping occurs when an input signal exceeds the input range of the amplifier hardware component that controls timing for reading from or writing to groups complementary metal oxide semiconductor common mode rejection ratio a measure of an instrument s ability to reject interference from a common mode signal usually expressed in decibels the smallest detectable change in an input voltage of a DAQ device the input range over which a circuit can handle a common mode signal the mathematical average voltage relative to the computer s ground of the signals from a differential input any voltage present at the instrumentation amplifier inputs with respect to amplifier ground the range of a parameter for which compensating adjustment can be made a method of triggering in which you simulate an analog trigger using software Also called software triggering device that transforms a signal from one form to another For example analog to digital converters ADCs for analog input digital to analog converters DACs for analog o
37. 0 kHz for example the antialias filters reject the monitor noise outside the frequency band of interest The frequency response inside the band of interest is not influenced if the sample rate were between approximately 21 6 and 28 kS s 6 8 National Instruments Corporation Chapter 6 Theory of Analog Operation Analog Output Circuitry NI4551 only The NI 4551 has two analog output channels either of which is illustrated in Figure 4 4 A common application for the analog output is to stimulate a system under test while measuring the response with the analog inputs The input and output sample clocks are synchronized and derived from the same DDS clock The input and output clocks can differ from each other by a factor of 2 1 2 4 8 128 while still maintaining their synchronization Output conversions occur simultaneously at software programmable rates from 1 25 to 51 2 kS s in increments of 47 684 15 5 The analog output circuitry uses eight times oversampling interpolators with 64 times oversampling delta sigma modulators to generate high quality signals The output channel has a range up to 10 V 7 07 Vms and can be driven as SE or DIFF The analog output also has an attenuation stage so you can choose attenuation of 0 20 or 40 dB Because of the delta sigma modulating DAC the instrument is immune to DNL distortion The analog output stage generates signals with extremely low noise and low distortion Be
38. 1 0 Signal Summary DO digital output Note pd pulldown Signal Type Protection Signal Name and Direction Impedance Volts Source Sink Bias DIO lt 0 31 gt DIO 40 5 3 5mA at 10 mA at 100 pd 24V 0 45 V DGND DIO 45V DO 0 15 Q Short circuit to 1A ground EXT TRIG DIO 40 5 3 5mA at 10 mA at 100 kQ pu 24V 0 45 V DIO digital input output pu pullup The tolerance on the 100 kQ resistors is very large Actual value may range between 20 and 100 kQ Analog Input Signal Connections N Caution signals NI 4551 4552 User Manual The analog input signals for the NI 4551 4552 instruments are lt 0 3 gt ACH lt 0 3 gt and AIGND The ACH lt 0 1 gt signals are tied to the two analog input channels of your NI 4551 and ACH lt 0 3 gt are tied to the four analog input channels of your NI 4552 instrument Exceeding the differential and common mode input ranges distorts your input AIGND is an analog input common signal that connects directly to the ground system on the NI 4551 4552 instruments You can use this signal for a general analog ground tie point to your NI 4551 4552 instrument if necessary but connecting AIGND to other earth connected grounds is not recommended AIGND is not directly available if you are using a BNC 2140 accessory 4 6 National Instruments Corporation Chapter 4 Sign
39. 3 6 input coupling 3 4 input mode 3 4 input polarity and range 3 4 to 3 5 input range selection considerations 3 5 to 3 6 National Instruments Corporation signal connections analog input stage figure 4 7 description 4 6 to 4 7 specifications A 1 to A 5 amplifier characteristics A 3 to A 4 channel characteristics A 1 to A 2 dynamic characteristics A 4 to A 5 transfer characteristics A 2 analog input circuitry 6 1 to 6 8 ADC 6 7 to 6 8 antialias filtering 6 3 to 6 7 calibration 6 2 input coupling 6 2 noise 6 8 analog I O connector signal descriptions pin assignments table 4 3 pin connections figure 4 2 signal summary table 4 4 analog operation theory 6 1 to 6 13 analog input circuitry 6 1 to 6 8 ADC 6 7 to 6 8 antialias filtering 6 3 to 6 7 calibration 6 2 input coupling 6 2 noise 6 8 analog output circuitry 6 10 to 6 13 anti image filtering 6 10 to 6 11 calibration 6 12 DAC 6 11 to 6 12 mute feature 6 12 to 6 13 analog output 3 6 to 3 7 output mode 3 6 output polarity and range 3 6 to 3 7 l 1 NI 4551 4552 User Manual Index signal connections analog output channel block diagram 4 9 description 4 8 to 4 10 specifications A 5 to A 7 channel characteristics A 5 to A 6 dynamic characteristics A 7 transfer characteristics A 6 voltage output A 6 analog output circuitry 6 10 to 6 13 anti image filtering 6 10 to 6 11 calibration 6 12 DAC 6 11 to 6 12 mute feature 6
40. 48 kS s The signal to THD plus noise ratio is 35 dB for the clipped waveform and 92 dB for the properly ranged waveform Notice that aliases of all the harmonics due to clipping appear in Figure 6 4 6 6 National Instruments Corporation Chapter 6 Theory of Analog Operation dB dB 0 0 20 20 40 40 60 60 80 80 100 M 100 120 120 140 140 0 5000 10000 15000 20000 25000Hz 0 5000 10000 15000 20000 25000Hz a Clipped Signal b Proper Signal Figure 6 4 Comparison of a Clipped Signal to a Proper Signal An overrange can occur on the analog signal as well as on the digitized signal Furthermore an analog overrange can occur independently from a digital overrange and vice versa For example a piezoelectric accelerometer may have a resonant frequency that when stimulated can produce an overrange in the analog signal but because the delta sigma technology of the ADC uses very sharp antialiasing filters the overrange is not passed into the digitized signal Conversely a sharp transient on the analog input may not overrange but due to the step response of those same delta sigma antialiasing filters the digitized data may be clipped The ADC The NI 4551 4552 ADCs use a method of A D conversion known as delta sigma modulation If the data rate is 204 8 kS s each ADC actually samples its input signal at 26 2144 MS s 128 times the data rate a
41. 52 has a bipolar input range of 20 V 10 V for a gain of 1 0 0 dB You can program the range settings on a per channel basis so that you can configure each input channel uniquely The software programmable gain on these instruments increases their overall flexibility by matching the input signal ranges to those that the ADC can accommodate With the proper gain setting you can use the full resolution of the ADC to measure the input signal Table 3 1 shows the overall input range and precision according to the input range configuration and gain used NI 4551 4552 User Manual 3 4 National Instruments Corporation Chapter 3 Hardware Overview Table 3 1 Actual Range and Measurement Precision of Input Linear Gain Gain Input Range Precision 0 1 20 dB 42 4 Vit 3 0518 mvt 0 316 10 dB 31 6 V 965 05 uV 1 0 0 dB 10 0 V 305 18 uV 3 16 10 dB 3 16 V 96 505 uV 10 20 dB 1 00 V 30 518 uV 31 6 30 dB 0 316 V 9 6505 uV 100 40 dB 0 100 V 3 0518 uV 316 50 dB 31 6mV 965 05 nV 1000 60 dB 10 0 mV 305 18 nV The value of 1 LSB of the 16 bit ADC that is the voltage increment corresponding to a change of one count in the ADC 16 bit count TT The actual input range is by design 100 V however the instrument is not tested or certified to operate in this range See Appendix A Specifications for absolute maximum ratings All data read from the ADC is interpreted as two s complement format
42. 551 4552 instrument is software configurable You can select different analog input configurations through application software The following sections describe in detail each of the analog input categories Input Mode The NI 4551 4552 instruments use differential DIFF inputs You can configure the input as a referenced single ended SE channel using the BNC 2140 DSA accessory For more information please refer to the BNC 2140 User Manual In DIFF mode one line connects to the positive input of the channel and the other connects to the negative input of the same channel You can connect the differential input to SE or DIFF signals either floating or ground referenced However grounding the negative input from floating sources may improve the measurement quality by removing the common mode noise Input Coupling The NI 4551 4552 has a software programmable switch that determines whether a capacitor is placed in the signal path If the switch is set for DC the capacitor is bypassed and any DC offset present in the source signal is passed to the ADC If the source has a significant amount of unwanted Offset bias voltage you must set the switch for AC coupling to place the capacitor in the signal path and take full advantage of the input signal range Input Polarity and Input Range The NI 4551 4552 instruments operate in bipolar mode Bipolar input means that the input voltage range is between V 2 and V 2 The NI 4551 45
43. AQ system is the video monitor Separate the monitor from the analog signals as much as possible 4 12 National Instruments Corporation Chapter 4 Signal Connections The following recommendations apply for all signal connections to digital signal routing from your NI 4551 4552 The digital output signal integrity is greatly influenced by the length of the cable being driven Minimize cable lengths and use schmitt trigger devices to deglitch signals Further conditioning may be required to create a clean signal Always try to couple a ground with a signal to minimize noise pickup and radiation The following recommendations apply for all signal connections to your NI 4551 4552 Separate NI 4551 4552 signal lines from high current or high voltage lines These lines can induce currents in or voltages on the NI 4551 4552 instrument 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 For more information refer to the application note Field Wiring and Noise Consideration for Analog Signals available from National Instruments
44. Computer Based Instruments NI 4551 4552 User Manual Dynamic Signal Acquisition Instruments for PCI NATIONAL _ P INSTRUMENTS April 1998 Edition The Software is the Instrument Part Number 321934A 01 Internet Support E mail support natinst com FTP Site ftp natinst com Web Address http www natinst com Bulletin Board Support BBS United States 512 794 5422 BBS United Kingdom 01635 551422 BBS France 01 48 65 15 59 Fax on Demand Support 512 418 1111 Telephone Support USA Tel 512 795 8248 Fax 512 794 5678 International Offices Australia 03 9879 5166 Austria 0662 45 79 90 0 Belgium 02 757 00 20 Brazil 011 288 3336 Canada Ontario 905 785 0085 Canada Qu bec 514 694 8521 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Hong Kong 2645 3186 Israel 03 6120092 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Mexico 5 520 2635 Netherlands 0348 433466 Norway 32 84 84 00 Singapore 2265886 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 200 51 51 Taiwan 02 377 1200 United Kingdom 01635 523545 National Instruments Corporate Headquarters 6504 Bridge Point Parkway Austin Texas 78730 5039 USA Tel 512 794 0100 Copyright 1998 National Instruments Corporation All rights reserved Important Information Warranty Copyright Trademarks The NI 4551 and NI 4552 are warranted against defects in materials and workmanship for a period of o
45. Figure 6 5c Still images remain and they must be filtered out Each output channel of the NI 4551 has discrete time switched capacitor and continuous time analog filters that remove the high frequency images as shown in Figure 6 5d NI 4551 4552 User Manual 6 10 National Instruments Corporation Chapter 6 Theory of Analog Operation Baseband Signal E L Images Amplitude Baseband Signal 8F 16 Fs Frequency a Spectrum of Sampled Signal Images after the Digital Filter A E e o E lt t F 8 Fs 16 F Frequency Baseband Signal b Spectrum of Signal after Digital Filter Images after the DAC o lt Fs 8 Fs 16 F Frequency c Spectrum of Signal after DAC Baseband Signal A lt gt 8F 16 F Frequency d Spectrum of Signal after Analog Filters The DAC National Instruments Corporation 6 11 Figure 6 5 Signal Spectra in the DAC The 64 times oversampling delta sigma DACSs on the NI 4551 work in the same way as delta sigma ADCS only in reverse The digital data first NI 4551 4552 User Manual Chapter 6 Theory of Analog Operation Calibration Mute Feature NI 4551 4552 User Manual passes through a digital lowpass filter and then goes to the delta sigma modulator In the ADC the delta sigma modulator is analog circuitry that converts
46. In external calibration you calibrate your instrument with a known external reference rather than relying on the onboard reference Redetermining the value of the onboard reference is part of this process and you can save the results in the EEPROM so you should not have to perform an external 5 2 National Instruments Corporation Chapter 5 Calibration calibration very often To externally calibrate your instrument call the NI DAQ calibration function You must be sure to use a very accurate external DC reference This reference should be several times more accurate than the instrument itself For example to calibrate the NI 4551 4552 the external reference should have a DC accuracy better than 115 ppm 0 001 dB Traceable Recalibration Traceable recalibration is divided into three different areas factory onsite and third party precision instruments typically require this type of recalibration every year If you require factory recalibration send your NI 4551 4552 back to National Instruments The instrument will be sent back to you with a new calibration certificate You can request a detailed report for an additional fee Please check with National Instruments for additional information such as cost and delivery times If your company has a metrology laboratory you can recalibrate the NI 4551 4552 at your location onsite You can also send out your NI 4551 4552 for recalibration by a third party Please contact Nation
47. Instruments timing bus that connects DAQ boards directly by means of connectors on top of the boards for precise synchronization of functions NI 4551 4552 User Manual Glossary S sample counter SE self calibrating Sensor settling time Shannon Sampling Theorem S H signal conditioning SNR software trigger software triggering source impedance NI 4551 4552 User Manual seconds samples the clock that counts the output of the channel clock in other words the number of samples taken On boards with simultaneous sampling this counter counts the output of the scan clock and hence the number of scans single ended a term used to describe an analog input that is measured with respect to common ground a property of a DSA board that has an extremely stable onboard reference and calibrates its own A D and D A circuits without manual adjustments by the user a device that responds to a physical stimulus heat light sound pressure motion flow and so on and produces a corresponding electrical signal the amount of time required for a voltage to reach its final value within specified limits a law of sampling theory stating that if a continuous bandwidth limited signal contains no frequency components higher than half the frequency at which it is sampled then the original signal can be recovered without distortion sample and hold a circuit that acquires and stores an analog voltage on a capac
48. National Instruments Corporation 4 13 NI 4551 4552 User Manual Calibration This chapter discusses the calibration procedures for your NI 4551 4552 instrument Your NI 4551 4552 is shipped with a calibration certificate The traceability information is stored in National Instruments corporate databases and is not actually shown on your certificate The certificate contains a unique tracking number linking your instrument to the database You can get a detailed calibration report from National Instruments for an additional charge If you are using NI DAQ that software includes calibration functions for performing all of the steps in the calibration process Calibration refers to the process of minimizing measurement and output voltage errors by making small circuit adjustments On the NI 4551 4552 instruments these adjustments take the form of writing values to onboard calibration DACs CalDACs Some form of instrument calibration is required for all but the most forgiving applications If you do not calibrate your instrument your signals and measurements could have very large offset and gain errors The four levels of calibration available are described in this chapter The first level is the fastest easiest and least accurate whereas the last level is the slowest most difficult and most accurate Loading Calibration Constants Your NI 4551 4552 instrument is factory calibrated before shipment at approximately 25 C to the level
49. abilities The level trigger circuit compares the full 16 bits of the programmed trigger level with the digitized 16 bit sample The trigger level range is identical to the analog input voltage range The National Instruments Corporation 3 7 NI 4551 4552 User Manual Chapter 3 NI 4551 4552 User Manual Hardware Overview trigger level resolution is the same as the precision for a given input range Refer to Table 3 1 for more information about input range and precision The trigger circuit generates an internal digital trigger based on the input signal and the user defined trigger levels Any of the timing sections of the timing input output TIO ASIC can use this level trigger including the analog input analog output RTSI and general purpose counter timer sections For example you can configure the analog input section to acquire a given number of samples after the analog input signal crosses a specific threshold As another example you can configure the analog output section to generate an output waveform whenever the analog input signal crosses a specific threshold Due to the nature of delta sigma converters the triggering circuits operate on the digital output of the converter Since the trigger is generated at the output of the converter triggers can occur only when a sample is actually generated Placing the triggering circuits on the digital side of the converter does not affect most measurements unless an analog output is
50. ader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident acti
51. al Instruments for approved third party calibration service providers National Instruments Corporation 5 3 NI 4551 4552 User Manual Theory of Analog Operation This chapter contains a functional overview and explains the operation of each analog functional unit making up the NI 4551 4552 See Figure 3 2 for a general block diagram of the NI 4551 4552 analog functions Analog Input Circuitry The NI 4551 has two identical analog input channels The NI 4552 has four identical analog input channels An analog input channel is illustrated in Figure 4 3 These input channels have 16 bit resolution and are simultaneously sampled at software programmable rates from 5 to 204 8 kS s in 190 7 uS s increments This flexibility in sample rates makes the instrument well suited for a wide variety of applications including audio and vibration analysis The differential analog inputs have AC DC coupling You can use a programmable gain amplifier stage on the inputs to select gains from 20 to 60 dB in 10 dB steps The input stage has differential connections allowing quiet measurement of either single ended or differential signals The analog inputs have both analog and real time digital filters implemented in hardware to prevent aliasing Input signals first pass through lowpass analog filters to attenuate signals with frequency components beyond the range of the ADCs Then digital antialiasing filters automatically adjust their cutoff freq
52. al Connections Figure 4 3 shows a diagram of your NI 4551 4552 instrument analog input stage 20 dB DC AC Coupling gt Analog NN M EE T a giis Lowpass Filter Calibration Multiplexer Converter pmeeemTA j NERA Gain 0 dB ity p Gain 10 dB d u Gain 20 dB fj 3 4Hz t Gain 30 dB Gain 40 dB AIGND Gain 0 dB Gain 50 dB 7v Gain 20 dB Gain 60 dB Figure 4 3 Analog Input Stage The analog input stage applies gain and common mode voltage rejection and presents high input impedance to the analog input signals connected to your NI 4551 4552 instrument Signals are routed directly to the positive and negative inputs of the analog input stage on the instrument The analog input stage converts two input signals to a signal that is the difference between the two input signals multiplied by the gain setting of the amplifier The amplifier output voltage is referenced to the ground for the instrument Your NI 4551 4552 instrument ADC measures this output voltage when it performs A D conversions Connection of analog input signals to your NI 4551 4552 instrument depends on the configuration of the input signal sources For most signals you use a DIFF configuration and connect the signal to ACHx where x is the NI 4551 4552 channel and the signal ground or signal minus as appropriate t
53. applications Eight of the 32 DIO signals are shown 4 10 National Instruments Corporation Chapter 4 Signal Connections 5 LED J Dos TTL Signal O DIO2 45V WW gt Switch yo DGND Connector Figure 4 5 Digital 1 0 Connections Figure 4 5 shows DIO lt 0 3 gt configured for digital input and DIO lt 4 7 gt configured for digital output Digital input applications include receiving TTL signals and sensing external device states such as the state of the switch shown in Figure 4 5 Digital output applications include sending TTL signals and driving external devices such as the LED shown in Figure 4 5 National Instruments Corporation 4 11 NI 4551 4552 User Manual Chapter 4 Signal Connections Digital Power Connections Four pins on the digital I O connector supply 5 V from the computer power supply via a self resetting fuse The fuse will reset automatically within a few seconds after the overcurrent condition is removed These pins are referenced to DGND and you can use them to power external digital circuitry The following is the power rating for the fuse e Power rating 4 65 to 5 25 VDC at 1 A Take careful consideration of the current drawn from the DIO connector Although the fuse allows a 1 A current draw system specifications can limit the current draw to less than 1 A
54. ations Dynamic Characteristics Image free bandwidth DC to 0 450 f Image 90 dB 0 550 f lt four lt 63 450 f Spurious free dynamic range 90 dB DC to 100 kHz TAD a ek heehee gib 80 dB 90 dB forf lt 5 kHz or signal lt 1 Ving IMD iene eR 90 dB CCIF 14 kHz 15 kHz Crosstalk channel separation 80 dB DC to 23 kHz Phase linearity eee 1 Interchannel 1 same configuration both output channels Interchannel gain mismatch 0 1 dB for all attenuations same configuration both output channels Signal delay eR 34 6 0 5 sample periods any sample rate time from when digital data is expressed to when analog signal appears at output terminals Digital 1 0 Number of channels 32 input output Compatibility eee TTL CMOS National Instruments Corporation A 7 NI 4551 4552 User Manual Appendix A Specifications Triggers NI 4551 4552 User Manual Digital logic levels Level Min Max Input low voltage 0 0 V 0 8 V Input high voltage 2 0V 5 0V Input low current 20V 10 pA Input high current V 5V 10 uA Output low voltage 1 10mA 0 45 V OL Output high voltage 1 23 5mA 24 OH Power on stat
55. cause the instrument has a 93 dB dynamic range it is possible to generate low noise waveforms The instrument also has excellent amplitude flatness of 0 2 dB within the frequency range of DC to 23 kHz and has a total harmonic distortion THD of 95 dB at 1 kHz With these specifications you are assured of the quality and integrity of the output signals generated Anti Image Filtering A sampled signal repeats itself throughout the frequency spectrum These repetitions begin above one half the sample rate F and at least in theory continue up through the spectrum to infinity as shown in Figure 6 5a Because the sample data actually represents only the frequency components below one half the sample rate the baseband it is better to filter out all these extra images of the signal The NI 4551 accomplishes this filtering in two stages First the data is digitally resampled at eight times the original sample rate Then a linear phase digital filter removes almost all energy above one half the original sample rate and sends the data at the eight times rate to the DAC as shown in Figure 6 5b Some further inherent filtering occurs at National Instruments Corporation 6 9 NI 4551 4552 User Manual Chapter 6 Theory of Analog Operation the DAC because the data is digitally sampled and held at eight times the sample rate This filtering has a sin x x response yielding nulls at multiples of eight times the sample rate as shown in
56. ctors 4 1 to 4 6 68 pin digital connector pin connections figure B 2 analog I O pin assignments table 4 3 NI 4551 4552 User Manual Index analog I O pin connections figure 4 2 analog I O signal summary table 4 4 digital I O pin assignments table 4 6 digital I O signal summary table 4 6 digital pin connections figure 4 5 exceeding maximum ratings warning 4 1 power connections 4 10 types of signal sources 4 8 floating 4 8 ground referenced 4 8 software installation 2 1 software programming choices 1 3 to 1 4 ComponentWorks 1 4 LabVIEW and LabWindows CVI 1 3 Measure 1 4 National Instruments application software 1 3 to 1 4 VirtualBench 1 3 to 1 4 specifications analog input A 1 to A 5 amplifier characteristics A 3 to A 4 channel characteristics A 1 to A 2 dynamic characteristics A 4 to A 5 transfer characteristics A 2 analog output A 5 to A 7 channel characteristics A 5 to A 6 dynamic characteristics A 7 transfer characteristics A 6 voltage output A 6 analog trigger A 8 bus interface A 9 calibration A 10 digital I O A 7 to A 8 digital trigger A 9 environment A 10 onboard calibration reference A 5 NI 4551 4552 User Manual 1 6 physical A 10 power requirements A 9 T technical support C 1 to C 2 telephone and fax support numbers C 2 theory of operation See analog operation theory timing signal routing 3 11 traceable recalibration 5 3
57. d National Instruments products are NOT intended to be a substitute for any form of established process procedure or equipment used to monitor or safeguard human health and safety in medical or clinical treatment Contents About This Manual Organization of This Manual sees nennen nennen ix Conventions Used in This 1 National Instruments Documentation enne ener nennen nnns xi Related 1 Customer Communication xi Chapter 1 Introduction What You Need to Get Started esses eene eet tnn 1 2 Unpacking 5 eI iei EORR Tea e ete 1 2 Software Programming Choices 2 1 3 National Instruments Application Software 1 3 Optional Equipment npe E pH e REESE Erreur eed 1 4 Custom Cabling 5 a tette teet o IE tee pits 1 5 Chapter 2 Installation and Configuration Software Installation cere rote ure pe ixi 2 1 Hardware Installation eet ee teet eterne iere vue fce e 2 1 Instrument Configuration eren en nennen trennen tenentes 2 2 Chapter 3 Hardware Overview Anglos Input 5n ert ea op cubos gei te tte tentes 3 4 Input Mode 5 eeu E ERR Rae hea
58. data to from a computer system involving communications channels operator interface devices and or data acquisition and control interfaces current output high current output low interrupt request a type of signal conditioning in which you isolate the transducer signals from the computer for safety purposes This protects you and your computer from large voltage spikes and makes sure the measurements from the DAQ device are not affected by differences in ground potentials the voltage that an isolated circuit can normally withstand usually specified from input to input and or from any input to the amplifier output or to the computer bus G 10 National Instruments Corporation kbytes s kS Kword L LabVIEW latched digital I O library linearity linearization low frequency corner LSB National Instruments Corporation G 11 Glossary kilo the standard metric prefix for 1 000 or 10 used with units of measure such as volts hertz and meters kilo the prefix for 1 024 or 210 used with B in quantifying data or computer memory a unit for data transfer that means 1 024 bytes s 1 000 samples 1 024 words of memory laboratory virtual instrument engineering workbench a type of digital acquisition generation where a device or module accepts or transfers data after a digital pulse has been received Also called handshaked digital I O a file containing compiled object modules each comprised of o
59. e seseeeeeeereneere Input High Z Data transfers eee Programmed I O Analog Trigger Source NE455 15 52 ACH lt 0 1 gt NI4552 ACH 0 3 Level ethan hie di EE full scale Slope pea mp Positive or negative software selectable Resolution eerte 16 bits HySteTESIS Programmable A 8 National Instruments Corporation Digital Trigger Compatibility eese RESPONSE i eura neret etes Pulse width seen Bus Interface Power Requirement Power NI 4551 Power NI 4552 sees Available power eese analog I O connector Available digital I O connector Power consumption can vary based on instrument personality National Instruments Corporation A 9 Appendix A Specifications Rising or falling edge 10 ns min PCI Master Slave 5 V 2 8 A idle 3 8 A active typical 12 V 11 mA typical not including momentary relay switching 12 V 40 mA typical 13 3 V unused 5 3 3 A idle 4 3 A active typical 12 V 150 mA typical not including momentary relay switching 12 V unused 13 3 V unused 4 65 to 45 25 VDC at 0 5 A 4 65 to 45 25 VDC at 1 0 A NI 4551 4552 User Manual Appendix A Specifications Physical Dimensions esee 10 65 by 31
60. e 6 3 Figure 6 4 Figure 6 5 Figure A 1 Figure B 1 Digital Function Block Diagram eee 3 2 Analog Function Block Diagram 3 3 Below Low Level Triggering 3 9 Above High Level Triggering Mode sees 3 9 Inside Region Triggering Mode eee 3 10 High Hysteresis Triggering Mode eee 3 10 Low Hysteresis Triggering Mode sene 3 10 Analog Pin Connections eec e Ee tenens 4 2 Digital Pin Connections cece csecseceeceeeceeeeeeeseecaecseceseeeeeeseneeaee 4 5 Analog Input Stages cer t ee RH ttp rt 4 7 Analog Output Channel Block Diagram eee 4 0 Digital Connections eseseseeeeeeeeeeeenen nennen 4 11 Input Frequency Response ssseeeeeeeeneeeee eene 6 4 Input Frequency Response Near the Cutoff sss 6 5 Alias Rejection at the Oversample Rate esee 6 6 Comparison of a Clipped Signal to a Proper Signal 6 7 signal Spectra in tbe eere eee ee 6 11 Idle Channel Noise Typical eene A 4 68 Pin Digital Connector for Any Digital Accessory B 2 National Instruments Corporation Vii NI 4551 4552 User Manual Contents Tables Table 3 1 Actual Range and Measurement Precision of Input
61. e brackets containing numbers separated by an ellipsis represent a range of values associated with a bit or signal name for example DBIO lt 3 0 gt The symbol indicates that the text following it applies only to a specific product a specific operating system or a specific software version An asterisk following a signal name denotes an active low signal This icon to the left of bold italicized text denotes a note which alerts you to important information This icon to the left of bold italicized text denotes a caution which advises you of precautions to take to avoid injury data loss or a system crash Bold italic text denotes an activity objective note caution or warning DSA refers to dynamic signal acquisition Italic text denotes variables emphasis a cross reference or an introduction to a key concept This font also denotes text from which you supply the appropriate word or value as in NI DAQ 6 x SE refers to single ended and is equivalent to RSE referenced single ended X National Instruments Corporation About This Manual National Instruments Documentation The NI 4551 4552 User Manual is one piece of the documentation set for your system You could have any of several types of manuals depending on the hardware and software in your system Use the manuals you have as follows e Hardware documentation This manual presents information about using your instrument such as modes of operation
62. e gain of an amplifier from the ideal gain G 8 National Instruments Corporation GND grounded measurement system H h half power bandwidth handshaked digital I O hardware hardware triggering hysteresis Hz IC IMD National Instruments Corporation G 9 Glossary ground See SE hour the frequency range over which a circuit maintains a level of at least 3 dB with respect to the nominal level a type of digital acquisition generation where a device or module accepts or transfers data after a digital pulse has been received Also called latched digital I O the physical components of a computer system such as the circuit boards plug in boards chassis enclosures peripherals and cables aform of triggering where you set the start time of an acquisition and gather data at a known position in time relative to a trigger signal the lag between making a change and the effect of the change hertz cycles per second Specifically refers to the repetition frequency of a waveform integrated circuit intermodulation distortion the ratio in decibels of the total rms signal level of harmonic sum and difference distortion products to the overall rms signal level The test signal is two sine waves added together according to the following standards SMPTE A 60 Hz sine wave and a 7 kHz sine wave added in a 4 1 amplitude ratio DIN A 250 Hz sine wave and an 8 kHz sine wave added in a 4 1 a
63. e sensor a type of signal conditioning that uses external voltages and currents to excite the circuitry of a signal conditioning system into measuring physical phenomena the rate measured in bytes s at which data is moved from source to destination after software initialization and set up operations the maximum rate at which the hardware can operate any event that causes or starts some form of data capture transistor transistor logic a signal range that is always positive for example 0 to 10 V the output equivalent of a scan One or more analog or digital output samples Typically the number of output samples in an update is equal to the number of channels in the output group For example one pulse from the update clock produces one update which sends one new sample to every analog output channel in the group the number of output updates per second volts volts direct current G 18 National Instruments Corporation VI waveform word working voltage Z zero overhead looping zero wait state memory Glossary 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 volts input high volts input low volts in volts output high volts output low reference voltage multiple volta
64. etween two instruments connected to the same building power system is typically between 1 100 mV but can be much higher if power distribution circuits are not properly connected For this reason National Instruments does not recommend connecting AIGND to the source signal ground system since the difference between the grounds can induce currents in the NI 4551 4552 ground system Analog Output Signal Connections NI 4551 4552 User Manual The analog output signals for the NI 4551 instrument are DACOOUT DACOOUT DACIOUT DACIOUT and AOGND DACOOUT and DACOOUT are the plus and minus voltage output signals for analog output channel 0 DACIOUT and DACIOUT are the plus and minus voltage output signal for analog output channel 1 AOGND is a ground reference signal for both analog output channels It is connected directly to the ground system on the NI 4551 instrument You can use this signal for a general analog ground tie point to your NI 4551 instrument if necessary but connecting AOGND to other earth connected 4 8 National Instruments Corporation Chapter 4 Signal Connections grounds is not recommended AOGND is not directly available if you are using the BNC 2140 accessory The NI 4551 has two analog output channels either of which is illustrated in Figure 4 4 v 100 kQ 119 17777551 WWW 1 0 0 DAC XOUT C e Attenuator Differential NEM 210 ove Driver WQ 1 1 4 WN 03 9 DACXxOUT
65. g retry ribbon cable rise time ROM RSE RTSI bus National Instruments Corporation G 15 Glossary the inherent uncertainty in digitizing an analog value due to the finite resolution of the conversion process a device that maps a variable from a continuous distribution to a discrete distribution a property of an event or system in which data is processed as it is acquired instead of being accumulated and processed at a later time a measure in LSB of the linearity of an ADC It includes all non linearity and quantization errors It does not include offset and gain errors of the circuitry feeding the ADC the smallest signal increment that can be detected by a measurement system Resolution can be expressed in bits in proportions or in percent of full scale For example a system has 12 bit resolution one part in 4 096 resolution and 0 0244 of full scale a technique whereby a device is signaled not to use its local memory while the memory is in use from the bus an acknowledge by a destination that signifies that the cycle did not complete and should be repeated a flat cable in which the conductors are side by side the difference in time between the 10 and 90 points of a system s step response root mean square the square root of the average value of the square of the instantaneous signal amplitude a measure of signal amplitude read only memory see SE real time system integration bus the National
66. g Mode National Instruments Corporation 3 9 NI 4551 4552 User Manual Chapter 3 Hardware Overview In inside region triggering mode the trigger is generated when the signal value is between the lowValue and the highValue highValue lowValue I EL Figure 3 5 Inside Region Triggering Mode In high hysteresis triggering mode the trigger is generated when the signal value is greater than high Value with the hysteresis specified by lowValue high Value lowValue Trigger Figure 3 6 High Hysteresis Triggering Mode In low hysteresis triggering mode the trigger is generated when the signal value is less than lowValue with the hysteresis specified by highValue highValue TN ey a ee EN lowValue Y ALL LL Takes gt Trigger Figure 3 7 Low Hysteresis Triggering Mode NI 4551 4552 User Manual 3 10 National Instruments Corporation RTSI Triggers Digital 1 0 Chapter 3 Hardware Overview You can use digital triggering through the RTSI bus and the external digital 50 pin connector EXT_TRIG is the pin dedicated to external digital triggering You can use the digital trigger to start an acquisition a waveform generation or to synchronize the start of a simultaneous acquisition and waveform generation You can trigger the
67. ge readings taken at a specific sampling rate the standard number of bits that a processor or memory manipulates at one time Microprocessors typically use 8 16 or 32 bit words the highest voltage that should be applied to a product in normal use normally well under the breakdown voltage for safety margin the ability of a high performance processor to repeat instructions without requiring time to branch to the beginning of the instructions memory fast enough that the processor does not have to wait during any reads and writes to the memory National Instruments Corporation G 19 NI 4551 4552 User Manual Index Numbers 5 V signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 analog power connections 4 10 digital I O pin assignments table 4 6 digital I O signal summary table 4 6 digital power connections 4 12 self resetting fuse 4 10 4 12 A AC input coupling 3 4 ACH lt 0 3 gt signal analog I O pin assignments table 4 3 analog I O signal connections 4 7 analog I O signal summary 4 4 ACH lt 0 3 gt signal analog I O pin assignments table 4 3 analog I O signal connections 4 7 analog I O signal summary 4 4 ADC 6 7 to 6 8 AIGND signal analog input signal connections 4 6 to 4 7 analog I O pin assignments table 4 3 analog I O signal summary 4 4 amplifier characteristic specifications A 3 to A 4 analog function block diagram 3 3 analog input 3 4 to
68. hat is built into the ADC chip This filter also has extremely flat frequency response and no phase error but its roll off near the cutoff frequency about 0 493 times the sample rate is extremely sharp and the rejection above 0 536 times the sample rate is greater than 85 dB The output stage of the digital filter resamples the higher frequency data stream at the output data rate producing 16 bit digital samples With the NI 4551 4552 filters you have the complete antialiasing protection needed to sample signals accurately The digital filter in each channel passes only those signal components with frequencies that lie below the Nyquist frequency or within one Nyquist bandwidth of multiples of 128 times the sample rate The analog filter in each channel rejects possible aliases mostly noise from signals that lie near these multiples Figures 6 1 and 6 2 show the frequency response of the NI 4551 4552 input circuitry Amplitude dB 0 00 20 00 40 00 60 00 80 00 100 00 120 00 0 00 0 20 0 40 0 60 0 80 1 00 Frequency Sample Rate f NI 4551 4552 User Manual Figure 6 1 Input Frequency Response 6 4 National Instruments Corporation Chapter 6 Theory of Analog Operation Amplitude dB 0 00 1 00 2 00 3 00 4 00 5 00 6 00 0 43 0 44 0 45 0 46 0 47 0
69. ication Initiate self calibration to minimize the effects of any offset and gain drifts particularly those due to warmup Your NI 4551 4552 instrument has an onboard calibration reference to ensure the accuracy of self calibration Its specifications are listed in Appendix A Specifications The reference voltage is measured at the factory and stored in the EEPROM for subsequent self calibrations Immediately after self calibration the only significant residual calibration error could be gain error due to time or temperature drift of the onboard voltage reference This error is addressed by external calibration which is discussed in the following section External Calibration If you are interested primarily in relative measurements you can ignore a small amount of gain error and self calibration should be sufficient To calibrate your NI 4551 4552 device while it is connected to a BNC 2140 accessory set each input channel to SE and connect each channel terminal to a channel terminal through a BNC shunt You can also calibrate your NI 4551 4552 device by removing the external cable connected to the BNC 2140 accessory External Calibration NI 4551 4552 User Manual The onboard calibration reference voltage is stable enough for most applications but if you are using your instrument at an extreme temperature or if the onboard reference has not been measured for a year or more you should externally calibrate your instrument
70. igh accuracy and fidelity without introducing noise or out of band aliases Applications include audio signal processing and analysis acoustics and speech research sonar audio frequency test and measurement vibration and modal analysis or any application requiring high fidelity signal acquisition of signals with a bandwidth up to 95 kHz or signal generation with a bandwidth up to 23 kHz National Instruments Corporation 1 1 NI 4551 4552 User Manual Chapter 1 Introduction What You Need to Get Started Unpacking To set up and use your NI 4551 or NI 4552 you will need the following 0 One of the following instruments NI 4551 NI 4552 LY NI4551 4552 User Manual L Dynamic Signal Analyzer Software CD C You may have one or more of the following software packages and documentation LabVIEW for Windows LabWindows CVI for Windows NI DAQ for PC Compatibles VirtualBench DSA ComponentWorks Measure C Your computer C SHC68 C68 A1 analog cable CL BNC 2140 accessory NI 4551 4552 User Manual Your NI 4551 4552 is shipped in an antistatic plastic package to prevent electrostatic damage to the instrument Electrostatic discharge can damage components on the instrument To avoid such damage in handling the instrument take the following precautions e Ground yourself via a grounding strap or by holding a grounded object e Touch the plastic package to a metal part of your computer chassis before remo
71. ime between failure mean time to repair predicts downtime and how long it takes to fix a product normally closed or not connected National Instruments driver software for DAQ hardware National Institute of Standards and Technology 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 atype of digital acquisition generation where LabVIEW updates the digital lines or port states immediately or returns the digital value of an input line Also called immediate digital I O or non handshaking G 12 National Instruments Corporation nonreferenced signal sources NRSE Nyquist Frequency 0 onboard channels operating system optical isolation output settling time output slew rate P passband pattern generation National Instruments Corporation G 13 Glossary signal sources with voltage signals that are not connected to an absolute reference or system ground Also called floating signal sources Some common example of nonreferenced signal sources are batteries transformers or thermocouples nonreferenced single ended mode all measurements are made with respect to a common NRSE measurement sys
72. ing If the signal in the previous example is not a sine wave the signal can have many components harmonics that lie above the Nyquist frequency If present these harmonics are erroneously aliased back into the baseband and added to the parts of the signal that are sampled accurately producing a distorted sampled data set Input to the sampler only those signals that can be accurately represented All frequency components of such signals lie below the Nyquist frequency To make sure that only those signals go into the sampler a lowpass filter is applied to signals before they reach the sampler The NI 4551 4552 has complete antialiasing filters The NI 4551 4552 includes two stages of antialias filtering in each input channel lowpass filter This filter has a cutoff frequency of about 4 MHz and a rejection of greater than 40 dB at 20 MHz Because its cutoff frequency is significantly higher than the data sample rate the analog filter has an extremely flat frequency response in the bandwidth of interest and it has very little phase error The analog filter precedes the analog sampler which operates at 128 times the selected sample rate 26 2144 MS s in the case of a 204 8 kS s sample rate and is actually a 1 bit ADC The 1 bit 128 times oversampled data National Instruments Corporation 6 3 NI 4551 4552 User Manual Chapter 6 Theory of Analog Operation that the analog sampler produces is passed on to a digital antialiasing filter t
73. ion of code widths from their ideal value of 1 LSB performing frequency division on an internal signal software that controls a specific hardware device such as a DAQ board or a GPIB interface board the ratio of the largest signal level a circuit can handle to the smallest signal level it can handle usually taken to be the noise level normally expressed in decibels electrically erasable programmable read only memory ROM that can be erased with an electrical signal and reprogrammed electromechanical compliance a device that converts linear or rotary displacement into digital or pulse signals The most popular type of encoder is the optical encoder which uses a rotating disk with alternating opaque areas a light source and a photodetector erasable programmable read only memory ROM that can be erased usually by ultraviolet light exposure and reprogrammed the condition or state of an analog or digital signal an onboard EEPROM that may contain device specific initialization and system boot functionality external digital trigger a voltage pulse from an external source that triggers an event such as A D conversion NI 4551 4552 User Manual Glossary F false triggering FIFO filtering FIR flash ADC floating signal sources Fs ft G gain gain accuracy NI 4551 4552 User Manual triggering that occurs at an unintended time first in first out memory buffer the first data stored is the fir
74. itor for a short period of time the manipulation of signals to prepare them for digitizing signal to noise ratio the ratio of the overall rms signal level to the rms noise level expressed in decibels a programmed event that triggers an event such as data acquisition a method of triggering in which you simulate an analog trigger using software Also called conditional retrieval 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 G 16 National Instruments Corporation SS S s STC switchless device synchronous system noise system RAM TC T H THD THD N throughput rate National Instruments Corporation G 17 Glossary simultaneous sampling a property of a system in which each input or output channel is digitized or updated at the same instant samples per second used to express the rate at which a DAQ board samples an analog signal system timing controller devices that do not require dip switches or jumpers to configure resources on the devices also called Plug and Play devices 1 hardware a property of an event that is synchronized to a reference clock 2 software a property of a function that begins an operation and returns only when the operation is complete a measure of the amount of noise seen by an analog circuit or an ADC when the analog inputs are gr
75. l support centers which are staffed by applications engineers Electronic Services Bulletin Board Support National Instruments has BBS and FTP sites dedicated for 24 hour support with a collection of files and documents to answer most common customer questions From these sites you can also download the latest instrument drivers updates and example programs For recorded instructions on how to use the bulletin board and FTP services and for BBS automated information call 512 795 6990 You can access these services at United States 512 794 5422 Up to 14 400 baud 8 data bits 1 stop bit no parity United Kingdom 01635 551422 Up to 9 600 baud 8 data bits 1 stop bit no parity France 01 48 65 15 59 Up to 9 600 baud 8 data bits 1 stop bit no parity FTP Support To access our FTP site log on to our Internet host ftp natinst com aS anonymous and use your Internet address such as joesmith anywhere com as your password The support files and documents are located in the support directories National Instruments Corporation C 1 NI 4551 4552 User Manual Fax on Demand Support Fax on Demand is a 24 hour information retrieval system containing a library of documents on a wide range of technical information You can access Fax on Demand from a touch tone telephone at 512 418 1111 E Mail Support Currently USA Only You can submit technical support questions to the applications engineering team through e mail at the Internet
76. l to use the SE configuration and connect the floating ground system of the instrument to AOGND to reduce common mode noise coupled from an interfering source to the National Instruments Corporation 4 9 NI 4551 4552 User Manual Chapter 4 Signal Connections instrument You can make DIFF and SE connections through the BNC 2140 accessory Analog Power Connections Two pins on the analog I O connector supply 5 V from the computer power supply via a self resetting fuse The fuse resets automatically within a few seconds after the overcurrent condition is removed These pins are referenced to DGND and you can use them to power external analog accessories like the BNC 2140 The following is the power rating for the fuse e Power rating 4 65 to 45 25 VDC at 0 5 A AN Caution Do not under any circumstances connect these 5 V power pins directly to analog ground digital ground or to any other voltage source on the NI 4551 4552 or any other device Doing so can damage the NI 4551 4552 and the computer National Instruments is not liable for damages resulting from such a connection Digital 1 0 Signal Connections NI 4551 4552 User Manual The digital I O signals are DIO lt 0 31 gt and DGND DIO lt 0 31 gt are the signals making up the DIO port DGND is the ground reference signal for the DIO port You can program all lines individually to be inputs or outputs Figure 4 5 shows signal connections for three typical digital I O
77. log input circuitry 6 2 analog output circuitry 6 12 traceable recalibration 5 3 channel characteristic specifications analog input A 1 to A 2 analog output A 5 to A 6 ComponentWorks software 1 4 National Instruments Corporation configuration effect of sampling and update rates 3 12 to 3 13 instrument configuration 2 2 connectors See I O connectors customer communication xi C 1 to C 2 D DAC mute feature 6 12 to 6 13 signal spectra in DAC figure 6 11 theory of operation 6 11 to 6 12 DACOOUT signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 analog output signal connections 4 8 to 4 9 DACOOUT signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 analog output signal connections 4 8 to 4 9 DAC1OUT signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 analog output signal connections 4 8 to 4 9 DACIOUT signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 analog output signal connections 4 8 to 4 9 DC input coupling 3 4 DDS direct digital synthesis technology 3 12 delta sigma modulation analog input circuitry 6 7 analog output circuitry 6 9 overview 1 1 triggering effect 3 8 National Instruments Corporation I 3 Index DGND signal analog I O pin assignments table 4 3 analog I O signal summary table 4 4 digital I O pin assignments table 4 6
78. ls from sensors transducers and test probes or fixtures and inputting them to a computer for processing 2 collecting and measuring the same kinds of electrical signals with A D and or DIO boards plugged into a computer and possibly generating control signals with D A and or DIO boards in the same computer decibel the unit for expressing a logarithmic measure of the ratio of two signal levels dB 20log 0 V V gt for signals in volts direct current NI 4551 4552 User Manual Glossary DC coupled DDS default setting delta sigma modulating ADC device DGND DIFF differential input differential measurement system digital port digital trigger DIO DMA NI 4551 4552 User Manual allowing the transmission of both AC and DC signals direct digital synthesis a default parameter value recorded in the driver In many cases the default input of a control is a certain value often 0 that means use the current default setting For example the default input for a parameter may be do not change current setting and the default setting may be no AMUX 64T boards If you do change the value of such a parameter the new value becomes the new setting You can set default settings for some parameters in the configuration utility or manually using switches located on the device a high accuracy circuit that samples at a higher rate and lower resolution than is needed and by means of feedback loops pushes the quantization
79. mable switch to individually configure each input channel for AC or DC coupling If the switch is set for DC the capacitor is bypassed and any DC offset present in the source signal passes to the ADC The DC configuration is preferred because it places one less component in the signal path and thus has higher fidelity The DC configuration is recommended if the signal source has only small amounts of offset voltage less than 100 mV or if the DC content of the acquired signal is important If the source has a significant amount of unwanted offset or bias voltage you must set the switch for AC coupling to take full advantage of the input signal range Using AC coupling results in a drop in the low frequency response of the analog input The 3 dB cutoff frequency is approximately 3 4 Hz but the 0 01 dB cutoff frequency for instance is considerably higher at approximately 70 5 Hz The input coupling switch can connect the input circuitry to ground instead of to the signal source This connection is usually made during offset calibration which is described in Chapter 5 Calibration The NI 4551 4552 analog inputs have calibration adjustments Onboard CalDACSs remove the offset and gain errors for each channel For complete calibration instructions refer to Chapter 5 Calibration A sampling system such as an ADC can represent only signals of limited bandwidth Specifically according to the Shannon Sampling Theorem a sampling rate
80. modify these settings through National Instruments application level software such as ComponentWorks LabVIEW LabWindows CVI and VirtualBench or driver level software such as NI DAQ 2 2 National Instruments Corporation Hardware Overview This chapter presents an overview of the hardware functions on your NI 4551 4552 instrument Figure 3 1 shows a block diagram of the digital functions Figure 3 2 shows a block diagram of the analog functions The two function blocks connect through the analog mezzanine bus National Instruments Corporation 3 1 NI 4551 4552 User Manual Chapter 3 Hardware Overview Analog Mezzanine Bus To Analog Section i A Z Direct Digital Analog Synthesis Clock Mezzanine Clock Control Control Generator General Data o Control E Functions Manager 5 7 EE EN Digital O gt Local Local ibi i NE SRAM DRAM A v Address Decode DMA Control Bus FIFO gt Arbiter Control AlL FIFO j y 1 1 PCI Controller TAO FIFO is used only PCI Bus on NI 4551 Figure 3 1 Digital Function Block Diagram NI 4551 4552 User Manual 3 2 National Instruments Corporation Hardware Overview Chapter 3
81. mplitude ratio CCIF A 14 kHz sine wave and a 15 kHz sine wave added in a 1 1 amplitude ratio inches NI 4551 4552 User Manual Glossary INL input bias current input impedance input offset current instrument driver instrumentation amplifier integrating ADC interrupt interrupt level I O isolation isolation voltage NI 4551 4552 User Manual integral nonlinearity a measure in LSB of the worst case deviation from the ideal A D or D A transfer characteristic of the analog I O circuitry the current that flows into the inputs of a circuit the measured resistance and capacitance between the input terminals of a circuit the difference in the input bias currents of the two inputs of an instrumentation amplifier a set of high level software functions that controls a specific GPIB VXI or RS 232 programmable instrument or a specific plug in DAQ board Instrument drivers are available in several forms ranging from a function callable language to a virtual instrument VI in LabVIEW a circuit whose output voltage with respect to ground is proportional to the difference between the voltages at its two inputs an ADC whose output code represents the average value of the input voltage over a given time interval a computer signal indicating that the CPU should suspend its current task to service a designated activity the relative priority at which a device can interrupt input output the transfer of
82. nch DSA is a turnkey application you can use to make measurements as you would with a stand alone dynamic analyzer ComponentWorks contains tools for data acquisition and instrument control built on NI DAQ driver software ComponentWorks provides a higher level programming interface for building virtual instruments with Visual Basic Visual C Borland Delphi and Microsoft Internet Explorer With ComponentWorks you can use all of the configuration tools resource management utilities and interactive control utilities included in NI DAQ Measure is a data acquisition and instrument control add in for Microsoft Excel With Measure you can acquire data directly from plug in DAQ boards GPIB instruments or serial RS 232 devices Measure has easy to use dialog boxes for configuring your measurements Your data is placed directly into Excel worksheet cells from which you can perform your analysis and report generation using the full power and flexibility of Excel Optional Equipment National Instruments offers a variety of products to use with your NI 4551 4552 series instruments including cables and connector blocks as follows e SHC50 68 digital cable Shielded and DIN rail mountable 68 pin connector blocks RTSI cables NI 4551 4552 User Manual 1 4 National Instruments Corporation Chapter 1 Introduction Custom Cabling National Instruments offers cables of different lengths and the BNC 2140 DSA accessory to connec
83. nd produces 1 bit samples that are applied to the digital filter This filter then expands the data to 16 bits rejects signal components greater than 102 4 KHz the Nyquist frequency and resamples the data at the more conventional rate of 204 8 kS s Although a 1 bit quantizer introduces a large amount of quantization error to the signal the 1 bit 26 MS s from the ADC carry all the information used to produce 16 bit samples at 204 8 kS s The delta sigma ADC achieves this conversion from high speed to high resolution by adding a large amount of random noise to the signal so that the resulting quantization noise although large is restricted to frequencies above 102 4 kHz This noise is not correlated with the input signal and is almost completely rejected by the digital filter National Instruments Corporation 6 7 NI 4551 4552 User Manual Chapter 6 Noise NI 4551 4552 User Manual Theory of Analog Operation The resulting output of the filter is a band limited signal with a dynamic range of over 90 dB One of the advantages of a delta sigma ADC is that it uses a 1 bit DAC as an internal reference whereas most 16 bit ADCs use 16 bit resistor network DACs or capacitor network DACs As a result the delta sigma ADC is free from the kind of differential nonlinearity DNL that is inherent in most high resolution ADCs This lack of DNL is especially beneficial when the ADC is converting low level signals in which noise and distortion
84. ne of more functions that can be linked to other object modules that make use of these functions NIDAQMSC LIB is a library that contains NI DAQ functions The NI DAQ function set is broken down into object modules so that only the object modules that are relevant to your application are linked in while those object modules that are not relevant are not linked the adherence of device response to the equation R KS where R response S stimulus and K a constant a type of signal conditioning in which software linearizes the voltage levels from transducers so the voltages can be scaled to measure physical phenomena in an AC coupled circuit the frequency below which signals are attenuated by at least 3 dB least significant bit NI 4551 4552 User Manual Glossary Mbytes s memory buffer MITE MS MSB MTBF MTTR NC NI DAQ NIST noise nonlatched digital I O NI 4551 4552 User Manual meters 1 Mega the standard metric prefix for 1 million or 106 when used with units of measure such as volts and hertz 2 mega the prefix for 1 048 576 or 220 when used with B to quantify data or computer memory a unit for data transfer that means 1 048 576 bytes s See buffer Interface to Everything a custom ASIC designed by National Instruments that implements the PCI bus interface The MITE supports bus mastering for high speed data transfers over the PCI bus million samples most significant bit mean t
85. ne 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 The media on which you receive National Instruments software are warranted not to fail to execute programming instructions due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this manual is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The re
86. nstruments Corporation Technical Support Form Photocopy this form and update it each time you make changes to your software or hardware and use the completed copy of this form as a reference for your current configuration Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently If you are using any National Instruments hardware or software products related to this problem include the configuration forms from their user manuals Include additional pages if necessary Name Company Address Fax Phone Computer brand Model Processor Operating system include version number Clock speed MHz RAM MB Display adapter Mouse yes no Other adapters installed Hard disk capacity MB Brand Instruments used National Instruments hardware product model Revision Configuration National Instruments software product Version Configuration The problem is List any error messages The following steps reproduce the problem NI 4551 4552 Hardware and Software Configuration Form Record the settings and revisions of your hardware and software on the line to the right of each item Complete a new copy of this form each time you revise your software or hardware configuration and use this form as a reference for your current configuration
87. o ACHx However if a signal has a high output impedance greater than 1 kQ and is floating you may find it useful to use an SE configuration and tether the signal minus to AIGND to reduce common mode interference You can make the DIFF and SE connections through the BNC 2140 accessory National Instruments Corporation 4 7 NI 4551 4552 User Manual Chapter 4 Signal Connections Types of Signal Sources When configuring the input channels and making signal connections first determine whether the signal sources are floating or ground referenced The following sections describe these two types of signals Floating Signal Sources A floating signal source does not connect in any way to the building ground system but instead has an isolated ground reference point Some examples of floating signal sources are outputs of transformers thermocouples battery powered devices optical isolator outputs and isolation amplifiers An instrument or device that has an isolated output is a floating signal source Ground Referenced Signal Sources A ground referenced signal source connects in some way to the building system ground and is therefore already connected to a common ground point with respect to the NI 4551 4552 instrument assuming that you plug the computer into the same power system Nonisolated outputs of instruments and devices that plug into the building power system fall into this category The difference in ground potential b
88. of F can only represent signals with a maximum frequency of 2 This maximum frequency is known as the Nyquist frequency If a signal is input to the sampling system with frequency components that exceed the Nyquist frequency the sampler cannot distinguish these parts of 6 2 National Instruments Corporation Chapter 6 Theory of Analog Operation the signal from some signals with frequency components less than the Nyquist frequency For example suppose an ADC is sampling at 1 000 S s If a 400 Hz sine wave is input the resulting samples accurately represent a 400 Hz sine wave However if a 600 Hz sine wave is input the resulting samples again appear to represent a 400 Hz sine wave because this signal exceeds the Nyquist frequency 500 Hz by 100 Hz In fact any sine wave with a frequency greater than 500 Hz that is input is represented incorrectly as a signal between 0 and 500 Hz The apparent frequency of this sine wave is the absolute value of the difference between the frequency of the input signal and the closest integer multiple of 1 000 Hz the sampling rate Therefore if a 2 325 Hz sine wave is input its apparent frequency is calculated as follows 2 325 2 1 000 325 Hz If a 3 975 Hz sine wave is input its apparent frequency is calculated as follows 4 1 000 3 975 25 Hz The process by which the sampler modulates these higher frequency signals back into the 0 through 500 Hz baseband is called alias
89. ol the NI 4551 The following sections describe in detail each of the analog output categories The NI 4551 instrument has two channels of analog output voltage at the I O connector The NI 4551 instrument uses DIFF outputs You can configure the outputs as an SE channel using the BNC 2140 DSA accessory For more information please refer to the BNC 2140 User Manual In DIFF mode one line connects to the positive input of the channel and the other connects to the negative input of that same channel You can connect the differential output to either SE or DIFF loads either floating or ground referenced However grounding the negative output is recommended when driving floating single ended loads Output Polarity and Output Range NI 4551 4552 User Manual The NI 4551 instrument operates in bipolar mode Bipolar output means that the output voltage range is between V 2 and V 2 The NI 4551 has a bipolar output range of 20 V 10 V for an attenuation of 1 0 0 dB 3 6 National Instruments Corporation Chapter 3 Hardware Overview You can program the range settings on a per channel basis so that you can configure each output channel uniquely The software programmable attenuation on these instruments increases their overall flexibility by matching the output signal ranges to your application Table 3 2 shows the overall output range and precision according to the attenuation used Table 3 2 Actual Range and Measurement Preci
90. ons of third parties or other events outside reasonable control Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation ComponentWorks CVI LabVIEW Measure NI DAQ and VirtualBench are trademarks of National Instruments Corporation Product and company names listed are trademarks or trade names of their respective companies WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS National Instruments products are not designed with components and testing intended to ensure a level of reliability suitable for use in treatment and diagnosis of humans Applications of National Instruments products involving medical or clinical treatment can create a potential for accidental injury caused by product failure or by errors on the part of the user or application designer Any use or application of National Instruments products for or involving medical or clinical treatment must be performed by properly trained and qualified medical personnel and all traditional medical safeguards equipment and procedures that are appropriate in the particular situation to prevent serious injury or death should always continue to be used when National Instruments products are being use
91. ounded RAM installed on a personal computer and used by the operating system as contrasted with onboard RAM terminal count the highest value of a counter track and hold a circuit that tracks an analog voltage and holds the value on command total harmonic distortion the ratio of the total rms signal due to harmonic distortion to the overall rms signal in decibel or a percentage signal to THD plus noise the ratio in decibels of the overall rms signal to the rms signal of harmonic distortion plus noise introduced the data measured in bytes s for a given continuous operation calculated to include software overhead NI 4551 4552 User Manual Glossary TIO transducer transducer excitation transfer rate trigger TTL U unipolar update update rate V V Vpc NI 4551 4552 User Manual timing input output the TIO ASIC is a timing and triggering controller It includes four general purpose counter timers used for applications such as event counting period and frequency measurement and pulse train generation The counters are a full 32 bits wide and include interfacing options for quadrature encoders and high frequency signals Additionally the TIO has a robust trigger routing and condition mechanism for connecting RTSI bus and board specific trigger and timing signals The TIO also provides advanced DIO capabilities for time stamping multiple I O lines and controlling digital output lines Se
92. phical programming language The LabVIEW Data Acquisition VI Library a series of VIs for using LabVIEW with National Instruments computer based instrument hardware is included with LabVIEW The LabVIEW Data Acquisition VI Library is functionally equivalent to the NI DAQ software LabWindows CVI features interactive graphics a state of the art user interface and uses the ANSI C programming language The LabWindows CVI Data Acquisition a series of functions for using LabWindows CVI with National Instruments computer based instruments hardware is included with the NI DAQ software kit The LabWindows CVI Data Acquisition library is functionally equivalent to the NI DAQ software VirtualBench is a suite of VIs for using your DAQ products just as you use standalone instruments but you benefit from processing display and National Instruments Corporation 1 3 NI 4551 4552 User Manual Chapter 1 Introduction storage capabilities of PCs VirtualBench instruments load and save waveform data to disk in the same forms used in popular spreadsheet programs and word processors A report generation capability complements the raw data storage by adding timestamps measurements user name and comments The complete VirtualBench suite contains VirtualBench Scope VirtualBench DSA VirtualBench FG VirtualBench Arb VirtualBench AODC VirtualBench DIO VirtualBench DMM and VitualBench Logger Your NI 4551 4552 comes with VirtualBench DSA VirtualBe
93. place ISA and EISA It is achieving widespread acceptance as a standard for PCs and work stations it offers a theoretical maximum transfer rate of 132 Mbytes s a measure of signal amplitude the difference between the highest and lowest excursions of the signal programmable function input devices that do not require DIP switches or jumpers to configure resources on the devices also called switchless devices 1 a communications connection on a computer or a remote controller 2 a digital port consisting of four or eight lines of digital input and or output the technique used on a DAQ board to acquire a programmed number of samples after trigger conditions are met an electrical device the resistance of which can be manually adjusted used for manual adjustment of electrical circuits and as a transducer for linear or rotary position parts per million the technique used on a DAQ board to keep a continuous buffer filled with data so that when the trigger conditions are met the sample includes the data leading up to the trigger condition the transmission of a signal through a computer system the amount of time required for a signal to pass through a circuit points multiple pulses a form of counter signal generation by which a pulse is outputted when a counter reaches a certain value G 14 National Instruments Corporation Q quantization error quantizer real time relative accuracy resolution resource lockin
94. re and Software Configuration Form in Appendix C Customer Communication of this manual Turn off and unplug your computer Remove the top cover or access port to the I O channel Remove the expansion slot cover on the back panel of the computer Insert the NI 4551 4552 instrument into a 5 V PCI slot It should fit snugly but do not force the instrument into place wa PF WN 6 Screw the mounting bracket of the NI 4551 4552 instrument to the back panel rail of the computer National Instruments Corporation 2 1 NI 4551 4552 User Manual Chapter 2 Installation and Configuration 7 Check the installation 8 Replace the cover 9 Plugin and turn on your computer The NI 4551 4552 instrument is now installed You are now ready to configure your software Instrument Configuration NI 4551 4552 User Manual The NI 4551 4552 instruments are completely software configurable However you must perform two types of configuration bus related and data acquisition related The NI 4551 4552 instruments are fully compatible with the industry standard PCI Local Bus Specification Revision 2 0 The PCI system automatically performs all bus related configurations and requires no interaction from you Bus related configuration includes setting the instrument base memory address and interrupt channel Data acquisition related configuration includes such settings as analog input polarity and range analog input mode and others You can
95. resetting analog power connections 4 10 digital power connections 4 12 G ground referenced signal sources 4 8 H hardware installation 2 1 to 2 2 hardware overview analog input 3 4 to 3 6 input mode 3 4 input polarity and range 3 4 to 3 5 input range selection considerations 3 5 to 3 6 analog output 3 6 to 3 7 analog trigger 3 7 to 3 11 block diagrams analog function 3 3 digital function 3 2 NI 4551 4552 User Manual l 4 digital I O 3 11 LEDs 3 13 timing signal routing 3 11 input coupling analog input 3 4 theory of operation 6 2 input mode 3 4 input polarity and range 3 4 to 3 5 actual range and measurement precision table 3 5 exceeding rated input voltages caution 3 5 selection considerations 3 5 to 3 6 installation hardware 2 1 to 2 2 software 2 1 unpacking NI 4451 4552 1 2 to 1 3 instrument configuration 2 2 I O connectors 4 1 to 4 6 developing cable connectors 1 5 exceeding maximum ratings warning 4 1 pin assignments table analog I O 4 3 digital I O 4 6 pin connections 68 pin digital connector figure B 2 analog figure 4 2 digital figure 4 5 signal summary table analog I O 4 4 digital I O 4 6 J jitter with triggering 3 8 National Instruments Corporation L LabVIEW and LabWindows CVI application software 1 3 LEDs 3 13 manual See documentation Measure software 1 4 mute feature 6 12 to 6 13 NI 4451 4552 See also hardware over
96. s This minimum rate is required to keep the internal circuitry of the converters running within specifications You are responsible for selecting sample and update rates that fall within the specified limits Failure to do so could greatly affect the specifications NI 4551 4552 LEDs The NI 4551 4552 has a green LED that flashes at power up This LED indicates that the onboard processor is running in the NI DAQ compatible mode and is ready to acquire or generate data In this mode the instrument acts as a standard DAQ device and you can program it using LabVIEW LabWindows CVI or any other supported National Instruments application software package The green LED may flash at a different rate when the NI 4551 4552 is accessed by VirtualBench DSA or by the instrument driver software The NI 4551 4552 has four red LEDs that National Instruments currently uses for internal debugging purposes The state of these red LEDs has no significance to your application National Instruments Corporation 3 13 NI 4551 4552 User Manual Signal Connections This chapter describes how to make input and output connections to your NI 4551 4552 instrument via the analog I O and digital I O connectors of the instrument The analog I O connector for the NI 4551 4552 connects to the BNC 2140 DSA accessory through the SHC68 C68 A 1 shielded cable You can access the analog I O of the NI 4551 4552 using standard BNC connectors on the BNC 2140 You can
97. s decreased bit one binary digit either 0 or 1 byte eight related bits of data an eight bit binary number Also used to denote the amount of memory required to store one byte of data the range of frequencies present in a signal or the range of frequencies to which a measuring device can respond a memory address that serves as the starting address for programmable registers All other addresses are located by adding to the base address a number system with a base of 2 a signal range that includes both positive and negative values for example 5 V to 5 V a type of coaxial signal connector a low pass filter having a very flat passband a very sudden sharp transition region and high rejection in the stopband temporary storage for acquired or generated data software a high speed data transfer in which the address of the data is sent followed by back to back data words while a physical signal is asserted the group of conductors that interconnect individual circuitry in a computer Typically a bus is the expansion vehicle to which I O or other devices are connected Examples of PC buses are the ISA and PCI bus a type of a plug in board or controller with the ability to read and write devices on the computer bus NI 4551 4552 User Manual Glossary C C CalDAC channel circuit trigger clip clock CMOS CMRR code width common mode range common mode signal common mode voltage compensation
98. s indicated in Appendix A Specifications The associated calibration constants the values that were written to the CalDACs to achieve calibration in the factory are stored in the onboard nonvolatile memory EEPROM Because the CalDACs have no memory capability they do not retain calibration information when the instrument is unpowered Loading calibration constants refers to the process of loading the CalDACs with the values stored in the EEPROM NI DAQ software determines when this is necessary and does it automatically The EEPROM contains a user modifiable calibration area in addition to the permanent factory calibration area This means that you can load the CalDACs with values either from the original factory calibration or from a calibration that you subsequently performed This method of calibration is National Instruments Corporation 5 1 NI 4551 4552 User Manual Chapter 5 Calibration not very accurate because it does not take into account the fact that the instrument measurement and output voltage errors can vary with time and temperature It is better to self calibrate when you install the instrument in your environment Self Calibration Your NI 4551 4552 can measure and correct for almost all of its calibration related errors without any external signal connections With National Instruments software you can self calibrate generally in less than a minute This is the preferred method of assuring accuracy in your appl
99. sion of Output Attenuation Linear Attenuation Range Precision 1 0 0 dB 10 0 V 305 18 uV 10 20 dB 1 00 V 30 158 uV 100 40 dB 0 100 V 3 0518 uV oo dB OV OV The value of 1 LSB of the 16 bit DAC that is the voltage increment corresponding to a change of one count in the DAC 16 bit count See Appendix A Specifications for absolute maximum ratings Note The instrument powers up in a mode with the outputs disabled anb infinitely attenuated Although these functions appear similar they are quite distinct and are implemented to protect your external equipment from startup transients When the DACs no longer have data written to them they automatically retransmit the last data point they received If you expect the data to return to 0 V or any other voltage level you must append the data to make it do so All data written to the DACs are interpreted as two s complement format In two s complement mode data values written to the analog output channel are either positive or negative Trigger In addition to supporting internal software triggering and external digital triggering to initiate a data acquisition sequence the NI 4551 4552 also supports analog level triggering You can configure the trigger circuit to monitor any one of the analog input channels to generate the level trigger Choosing an input channel as the level trigger channel does not influence the input channel cap
100. st data sent to the acceptor FIFOs are often used on DAQ devices to temporarily store incoming or outgoing data until that data can be retrieved or output For example an analog input FIFO stores the results of A D conversions until the data can be retrieved into system memory a process that requires the servicing of interrupts and often the programming of the DMA controller This process can take several milliseconds in some cases During this time data accumulates in the FIFO for future retrieval With a larger FIFO longer latencies can be tolerated In the case of analog output a FIFO permits faster update rates because the waveform data can be stored on the FIFO ahead of time This again reduces the effect of latencies associated with getting the data from system memory to the DAQ device atype of signal conditioning that allows you to attenuate unwanted portions of the signal you are trying to measure finite impulse response a non recursive digital filter with linear phase an ADC whose output code is determined in a single step by a bank of comparators and encoding logic signal sources with voltage signals that are not connected to an absolute reference or system ground Also called nonreferenced signal sources Some common example of floating signal sources are batteries transformers or thermocouples sample rate feet the factor by which a signal is amplified sometimes expressed in decibels a measure of deviation of th
101. t but each serves a separate purpose DACOOUT DACOOUT Output Analog Output Channel 0 This pin supplies the analog non inverting output channel 0 This pin is available only on the NI 4551 DACOOUT DACOOUT Output Analog Output Channel 0 This pin supplies the analog inverting output channel 0 This pin is available only on the NI 4551 DACIOUT DACIOUT Output Analog Output Channel 1 This pin supplies the analog non inverting output channel 1 This pin is only available on the NI 4551 DACIOUT 4DACIOUT Output Analog Output Channel 1 This pin supplies the analog inverting output channel 1 This pin is only available on the NI 4551 AOGND Ret Analog Output Ground The analog output voltages are ultimately referenced to this node AII three ground references AIGND AOGND and DGND are connected together on your NI 4551 4552 instrument but each serves a separate purpose 45V DGND Output 5 VDC Source These pins are fused for up to 0 5 A and supply power to the DSA signal conditioning accessories The fuse is self resetting DGND Digital Ground This pin supplies the reference for the 5 VDC supply All three ground references AIGND AOGND and DGND are connected together on your NI 4551 4552 instrument but each serves a separate purpose National Instruments Corporation 4 3 NI 4551 4552 User Manual
102. t cable plug part number 787131 1 e 50 position backshell with jackscrews part number 787233 1 Refer to Appendix B Pin Connections for pin assignments of digital accessories and cables National Instruments Corporation 1 5 NI 4551 4552 User Manual Installation and Configuration This chapter explains how to install and configure your NI 4551 4552 instrument Software Installation Note Install your software before you install your NI 4551 4552 instrument If you are using NI DAQ refer to your NI DAQ release notes Find the installation section for your operating system and follow the instructions given there If you are using LabVIEW LabWindows CVI or other National Instruments application software refer to the appropriate release notes After you have installed your application software refer to your NI DAQ release notes and follow the instructions given there for your operating system and application software package Hardware Installation You can install the NI 4551 4552 instrument in any available 5 V PCI expansion slot in your computer However to achieve the best noise performance leave as much room as possible between the NI 4551 4552 instrument and other devices and hardware The following are general installation instructions but consult your computer user manual or technical reference manual for specific instructions and warnings 1 Write down the instrument serial number in the NJ 4551 4552 Hardwa
103. t your analog I O to the NI 4551 4552 National Instruments recommends you do not develop your own cabling solution due to the difficulty of working with the high density connector and the need to maintain high signal integrity However if your application requires that you develop your own cable use the following guidelines e Use shielded twisted pair wires for each differential analog input or output channel pair Since the signals are differential using this type of wire yields the best results e When connecting the cable shields be sure to connect the analog input grounds to the AIGND pins and the analog output grounds to the AOGND pins For a connector pin assignment refer to Table 4 1 e To create your own accessories you can use AMP 68 pin right angle PWB receptacle header part number 787254 1 e Recommended manufacturer part numbers for the 68 pin mating connector for the cable assembly are as follows AMP 68 position straight cable plug part number 787131 3 68 position backshell with jackscrews part number 787191 1 National Instruments also offers cables of different lengths and accessories to connect your digital I O signals to the NI 4551 4552 To develop your own cable remember that the digital I O mating connector is a 50 position receptacle For a connector pin assignment refer to Table 4 3 Recommended manufacturer part numbers for this mating connector are as follows e 50 position straigh
104. tem reference but the voltage at this reference can vary with respect to the measurement system ground one half of Fs channels provided by the plug in data acquisition board base level software that controls a computer runs programs interacts with users and communicates with installed hardware or peripheral devices the technique of using an optoelectric transmitter and receiver to transfer data without electrical continuity to eliminate high potential differences and transients the amount of time required for the analog output voltage to reach its final value within specified limits the maximum rate of change of analog output voltage from one level to another the range of frequencies which a device can properly propagate or measure a type of handshaked latched digital I O in which internal counters generate the handshaked signal which in turn initiates a digital transfer Because counters output digital pulses at a constant rate this means you can generate and retrieve patterns at a constant rate because the handshaked signal is produced at a constant rate NI 4551 4552 User Manual Glossary PCI peak to peak PFI Plug and Play devices port posttriggering potentiometer ppm pretriggering propagation propagation delay pts pulse trains pulsed output NI 4551 4552 User Manual Peripheral Component Interconnect a high performance expansion bus architecture originally developed by Intel to re
105. transfer characteristic specifications analog input A 2 analog output A 6 triggers analog 3 7 to 3 11 above high level triggering mode figure 3 9 below low level triggering mode figure 3 9 high hysteresis triggering mode 3 10 inside region triggering mode figure 3 10 low hysteresis triggering mode 3 10 specifications A 8 digital specifications A 9 RTSI triggers 3 11 specifications A 8 to A 9 U unipolar input output See polarity selection unpacking NI 4451 4552 1 2 to 1 3 update clock frequency selecting 3 12 to 3 13 National Instruments Corporation Index V VirtualBench software 1 3 to 1 4 voltage output specifications A 6 W wiring considerations 4 12 to 4 13 National Instruments Corporation 1 7 NI 4551 4552 User Manual
106. type of signal conditioning that improves accuracy in the resulting digitized signal and reduces noise a measure of how close to constant the gain of a circuit remains over a range of frequencies a low pass filter preceding an ADC usually a brickwall filter that rejects signal energy above the Nyquist frequency 1 2 the sample rate of the ADC so that the ADC does not mistake out of band signals for in band signals a low pass filter after a DAC usually a brickwall filter that rejects signal energy above the Nyquist frequency 1 2 the sample rate of the DAC in order to suppress out of band images of the in band signal created by the D A conversion process analog output ground signal Application Specific Integrated Circuit a proprietary semiconductor component designed and manufactured to perform a set of specific functions for a specific customer 1 hardware a property of an event that occurs at an arbitrary time without synchronization to a reference clock 2 software a property of a function that begins an operation and returns prior to the completion or termination of the operation G 2 National Instruments Corporation attenuate attenuation ratio b B bandwidth base address binary bipolar BNC brickwall filter buffer burst mode bus bus master National Instruments Corporation G 3 Glossary to decrease the amplitude of a signal the factor by which a signal s amplitude i
107. uency to remove frequency components above half the programmed sampling rate Because of this advanced analog input design you do not have to add any filters to prevent aliasing These filters however cause a delay of 42 conversion periods between the input analog data and the digitized data The 90 dB dynamic range of the NI 4551 4552 instruments is the result of low noise and distortion and makes possible high accuracy measurements The instruments have excellent amplitude flatness of 0 1 dB and have a maximum total harmonic distortion THD specification of 92 dB at 1 kHz and a worst case THD of 80 dB at higher frequencies National Instruments Corporation 6 1 NI 4551 4552 User Manual Chapter 6 Theory of Analog Operation Input Coupling Calibration Antialias Filtering NI 4551 4552 User Manual State of the art 128 times oversampling delta sigma modulating ADCs achieve the low noise and low distortion of the NI 4551 4552 Because these ADCs sample at 128 times the specified sampling rate with 1 bit resolution they produce nearly perfect linearity Extremely flat linear phase lowpass digital filters then remove the quantization noise from outside the band of interest divide the sample rate by 128 and increase the resolution to 16 bits Using the delta sigma modulating ADCs the NI 4551 4552 are immune to the DNL distortion associated with conventional data acquisition devices The NI 4551 4552 has a software program
108. utput digital input or output ports and counter timers are conversion devices G 4 National Instruments Corporation conversion time counter timer coupling crosstalk current drive capability current sinking current sourcing D A DAC DACxOUT daisy chain DAQ dB DC National Instruments Corporation G 5 Glossary the time required in an analog input or output system from the moment a channel is interrogated such as with a read instruction to the moment that accurate data is available a circuit that counts external pulses or clock pulses timing the manner in which a signal is connected from one location to another an unwanted signal on one channel due to an input on a different channel the amount of current a digital or analog output channel is capable of sourcing or sinking while still operating within voltage range specifications the ability of a DAQ board to dissipate current for analog or digital output signals the ability of a DAQ board to supply current for analog or digital output signals digital to analog digital to analog converter an electronic device often an integrated circuit that converts a digital number into a corresponding analog voltage or current analog channel x output signal a method of propagating signals along a bus in which the devices are prioritized on the basis of their position on the bus data acquisition 1 collecting and measuring electrical signa
109. view custom cabling 1 5 optional equipment 1 4 overview 1 1 requirements for getting started 1 2 software programming choices 1 3 to 1 4 ComponentWorks 1 4 LabVIEW and LabWindows CVI 1 3 Measure 1 4 National Instruments application software 1 3 to 1 4 VirtualBench 1 3 to 1 4 unpacking 1 2 to 1 3 noise avoiding 4 12 to 4 13 6 8 Nyquist frequency 6 2 0 onboard calibration reference specifications A 5 optional equipment 1 4 output mode 3 6 output polarity and range 3 6 to 3 7 actual range and measurement precision table 3 7 power up modes note 3 7 National Instruments Corporation 1 5 physical specifications A 10 pin assignments analog I O table 4 3 digital I O table 4 6 pin connections figure 68 pin digital connector figure B 2 analog I O 4 2 digital I O 4 5 polarity selection analog input 3 4 to 3 5 actual range and measurement precision table 3 5 selection considerations 3 5 to 3 6 analog output 3 6 to 3 7 actual range and measurement precision 3 7 power connections analog power connections 4 10 digital power connections 4 12 power requirement specifications A 9 R recalibration traceable 5 3 requirements for getting started 1 2 RTSI trigger lines 3 11 S sample update clock frequency selecting 3 12 to 3 13 signal connections analog input 4 6 to 4 7 digital I O 4 10 to 4 11 field wiring considerations 4 12 to 4 13 I O conne
110. ving the instrument from the package 1 2 National Instruments Corporation Chapter 1 Introduction e Remove the instrument from the package and inspect the instrument for loose components or any other sign of damage Notify National Instruments if the instrument appears damaged in any way Do not install a damaged instrument into your computer e Never touch the exposed pins of connectors Software Programming Choices You have several options to choose from to program and use your National Instruments computer based instrument You can use National Instruments application software or the NI DAQ driver software The NI 4551 4552 can operate in two distinct modes that have different programming requirements When you operate the instrument in the instrument mode you must do all programming through the instrument driver When you operate the instrument in the NI DAQ compatible mode default state you must do all programming through NI DAQ National Instruments Application Software LabVIEW and LabWindows CVI are innovative program development software packages for data acquisition and control applications LabVIEW uses graphical programming whereas LabWindows CVI enhances traditional programing languages Both packages include extensive libraries for data acquisition instrument control data analysis and graphical data presentation LabVIEW features interactive graphics a state of the art user interface and a powerful gra

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