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NI 4472 User Manual - Department of Biomedical Engineering

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1. Figure 3 10 Inside Region Triggering Mode NI 4472 User Manual 3 12 ni com Chapter 3 Device Overview and Theory of Operation In high hysteresis triggering mode shown in Figure 3 11 the trigger is generated when the signal value is greater than highValue with the hysteresis specified by lowValue highValue lowValue Trigger Figure 3 11 High Hysteresis Triggering Mode In low hysteresis triggering mode shown in Figure 3 12 the trigger is generated when the signal value is less than lowValue with the hysteresis specified by highValue Trigger Figure 3 12 Low Hysteresis Triggering Mode You can use the EXT TRIG input SMB connector on the NI 4472 for dedicated external digital triggering Alternately you can trigger the NI 4472 from any other National Instruments device that has the RTSI bus feature You can programmatically route any PXI trigger to the NI 4472 except 5 5 which is reserved for internal use when synchronizing multiple NI 4472 devices Note PXI chassis with multiple PXI buses might not have RTSI connections across the bus boundaries National Instruments Corporation 3 13 NI 4472 User Manual Chapter 3 Device Overview and Theory of Operation Device and Clocks NI 4472 User Manual NI 4472 for PXI CompactPCI The NI 4472 for PXI CompactPCI can use either its int
2. 10 0 100 0 200 0 128 64f NI 4472 User Manual Figure 3 6 Alias Rejection at the Oversample Rate No filter can prevent a type of aliasing caused by a clipped or overranged waveform that is one that exceeds the voltage range of the ADC When clipping occurs the ADC assumes the closest value in its digital range to the actual value of the signal which is always either 8 388 607 223 1 or 8 388 608 273 Clipping 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 3 7 shows the spectra of 10 5 Vim and 10 0 Vims 3 0 KHz sine waves The signal to THD plus noise THD N ratio is 35 dB for the clipped waveform and 92 dB for the properly ranged waveform Aliases of all the harmonics due to clipping appear in Figure 3 7a 3 8 ni com Chapter 3 Device Overview and Theory of Operation 0 0 20 20 40 40 60 60 80 80 100 100 120 120 140 140 0 5000 10000 15000 20000 25000 0 5000 10000 15000 20000 25000 a Clipped Signal b Proper Signal
3. NI 4472 User Manual A 8 16 0 by 9 9 cm 6 3 by 3 9 in 1 3U CompactPCI slot 17 5 by 10 7 cm 6 9 by 4 2 in SMB male SMB male 0 to 50 C 20 to 70 C 10 to 90 RH non condensing On software command computes gain and offset corrections Whenever temperature is different from temperature at last internal calibration by more than 5 C Internal voltage reference read and stored in non volatile memory 2 years 15 minutes ni com Appendix A Specifications Safety Designed in accordance with e EN 61010 1 1993 A2 1995 61010 1 1990 A2 1995 e UL 3101 1 1993 UL 3111 1 1994 UL 3121 1998 e CAN CSA 22 2 no 1010 1 1992 A2 1997 Installation I Pollution degree sss 2 Electromagnetic Compatibility EMC EML ihre CE C Tick and FCC Part 15 Class A Compliant Electrical emissions esee EN 55011 Class A at 10m FCC Part 15A above 1 GHz Electrical immunity Evaluated to EN 61326 1997 A1 1998 Table 1 Note For full EMC compliance you must operate this device with shielded cabling In addition all covers and filler panels must be installed See the Declaration of Conformity DoC for this product for any additional regulatory compliance information To obtain the DoC for this product click Declaration of Conformity at com hardref nsf This w
4. The ADC Figure 3 7 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 might 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 might not overrange but due to the step response of those same delta sigma antialiasing filters the digitized data might be clipped The NI 4472 ADC uses a method of A D conversion known as delta sigma modulation If the data rate is 51 2 kS s each ADC actually samples its input signal at 6 5536 MS s 128 times the data rate and produces 1 bit samples that are applied to the digital filter This filter then expands the data to 24 bits rejects signal components greater than 25 6 kHz the Nyquist frequency and re samples the data at the more conventional rate of 51 2 kS s Although a 1 bit quantizer introduces a large amount of quantization error to the signal the 1 bit 6 5536 MS s from the ADC carry all the information used to produce 24 bit samples at 51 2 kS s The delta sigma ADC achieves this conversion from high speed to high resolution by adding a large a
5. Using PXI with CompactPCI section in Chapter 1 Getting Started with Your NI 4472 NI 4472 User Manual 2 2 ni com Chapter 2 Using Your NI 4472 3 Make sure there are no lighted LEDs on your chassis If any are lit wait until they go out before continuing your installation 4 Remove the filler panel for the slot you have chosen Ground yourself using a grounding strap or by touching a grounded object Follow the ESD protection precautions described in the Unpacking section of Chapter 1 Getting Started with Your NI 4472 6 Insert the NI 4472 for PXI CompactPCI into a 5 V PXI slot Use the injector ejector handle to fully insert the device into the chassis 7 Screw the front panel of the NI 4472 for PXI CompactPCI to the front panel mounting rail of the system 5 Note ensure a good ground connection securely fasten the front panel of NI 4472 for PXI CompactPCI to the chassis with the two screws attached for that purpose 8 Visually verify the installation Make sure the device is not touching other devices or components and is fully inserted in the slot 9 Plugin and turn on your computer The NI 4472 for PXI CompactPCI is now installed You are now ready to configure your NI 4472 device Testing Your Device The NI 4472 is completely software configurable The system software automatically allocates all device resources including base memory address and interrupt level This device does not require DMA con
6. V V for signals in volts absolute signal level compared to full scale direct current allowing the transmission of both AC and DC signals Direct Digital Synthesis clock a type of clock source with an output frequency controlled by a digital input word 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 devices 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 noise above the frequency range of interest This out of band noise is typically removed by digital filters a plug in data acquisition device card or pad that can contain multiple channels and 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 an analog input consisting of two terminals both of which are isolated from computer gro
7. 0 02 uF to ground The signal line of each analog input channel circuit NI 4472 User Manual 3 2 ni com Chapter 3 Device Overview and Theory of Operation is protected to 42 4 V whether power is on or off The shield side of the analog input channels has no overvoltage protection Do not apply a signal that varies by more than 2 5 V from the ground of the NI 4472 Analog Input Signal Connections Figure 3 3 shows a diagram of one of the eight identical NI 4472 analog input stages 24 V Compliant ICP Current Source ICP On Off E DC AC Common Mode Coupling Ghigke pr i Differentia Analog CHO Bu 0T Buffer 9 i 0 047 uF 5 Converter 0 01 uel X Calibration 1 MQ E Multiplexer Gain 12 77 dB 5 Figure 3 3 Analog Input Stage The analog input stage presents high input impedance to the analog input signals connected to your NI 4472 Signals are routed to the positive inputs of the analog input stage and their returns are routed to AIGND through a common mode choke Your NI 4472 ADCs measure these signals when they perform A D conversions These input channels have 24 bit resolution and are simultaneously sampled at software programmable rates from 102 4 kS s down to 1 0 kS s in 190 7 uS s increments for f gt 51 2 kS s or 95 37 uS s increments for National
8. 4 ni com Chapter 2 Using Your NI 4472 NATIONAL INSTRUMENTS NI 4472 FOR PXI IOE NI 4472 for PXI CompactPCI NI 4472 for PCI Figure 2 1 NI 4472 Front Panels National Instruments Corporation 2 5 NI 4472 User Manual Chapter 2 Using Your NI 4472 Before configuring the analog input channels and making signal connections you need to determine e Whether the input signal source is floating or grounded e Whether the accelerometer or microphone you are using requires ICP type current stimulation e Whether AC or DC coupling is best for your application e voltage range of the input signal Signal Sources The analog input channels of the NI 4472 have unbalanced differential inputs Figure 2 2 shows the input configurations for floating and grounded signal sources Floating NI 4472 Source CHn gt Signal 2 Ground Grounded Source NI 4472 CHn Signal Ground Figure 2 2 Input Configurations for the NI 4472 UN Caution Connecting a signal that varies more than 2 5 V from the ground reference of the NI 4472 to the ground shield of any analog input channel can result in inaccurate measurements or damage to your device National Instruments is not responsible for damage caused by such connections NI 4472 User Manual 2 6 ni com Chapter 2 Using Your NI 4472 Floating Signa
9. You can install the NI 4472 device in any available slot in your PCI bus computer or PXI CompactPCI chassis However to achieve best noise performance leave as much room as possible between the NI 4472 device 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 Note It is important to install the NI DAQ driver software before installing your NI 4472 device to ensure that the device is properly detected NI4472 for PCI Turn off and unplug your computer 2 Remove the cover 3 Make sure there are no lighted LEDs on your motherboard If any are lit wait until they go out before continuing your installation National Instruments Corporation 2 1 NI 4472 User Manual Chapter 2 Using Your NI 4472 4 Remove the expansion slot cover on the back panel of the computer 5 Ground yourself using a grounding strap or by touching a grounded object Follow the ESD protection precautions described in the Unpacking section of Chapter 1 Getting Started with Your NI 4472 6 Insert the NI 4472 for PCI into a PCI slot Gently rock the device to ease it into place It may be a tight fit but do not force the device into place 7 Screw the mounting bracket of the NI 4472 for PCI to the back panel rail of the computer Replace the cover 9 Plug in and turn on your computer Note For proper c
10. a grounded object e Touch the antistatic package to a metal part of your computer chassis before removing the device from the package UN Caution Never touch the exposed pins of connectors Remove the device from the package and inspect the device for loose components or any other sign of damage Notify National Instruments if the device appears damaged in any way Do not install a damaged device into your computer Store your NI 4472 in the antistatic envelope when not in use Software Programming Choices When programming your National Instruments DAQ hardware you can use National Instruments application development environment ADE software or other ADEs In either case you use NI DAQ National Instruments Application Software LabVIEW features interactive graphics a state of the art user interface and a powerful graphical programming language The LabVIEW Data Acquisition VI Library a series of virtual instruments for using LabVIEW with National Instruments DAQ hardware is included with LabVIEW The LabVIEW Data Acquisition VI Library is functionally equivalent to NI DAQ software Measurement Studio which includes LabWindows CVI tools for Visual C and tools for Visual Basic is a development suite that allows you to use ANSI C Visual C and Visual Basic to design your test and measurement software For C developers Measurement Studio includes LabWindows CVI a fully integrated ANSI C application development
11. 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 to decrease the amplitude of a signal the range of frequencies present in a signal or the range of frequencies to which a measuring device can respond a signal range that includes both positive and negative values for example 5 V to 5 V temporary storage for acquired or generated data software 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 G 2 ni com CCIF channel clip clock CMOS CMRR code width common mode range common mode signal conditional retrieval counter timer coupling crosstalk current sourcing National Instruments Corporation G 3 Glossary Celsius See IMD 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 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 mod
12. data acquisition sequence the NI 4472 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 capabilities The level trigger circuit compares the full 24 bits of the programmed trigger level with the digitized 24 bit sample 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 DAQ STC can use this level trigger including the analog input 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 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 generated based on the input trigger In this case you account for the inherent delays of the finite impulse response FIR filters internal to the delta sigma converters The delay through the input converter is 38 8 sample periods During repetitive sampling
13. data at the same rate One input channel cannot acquire data at a different rate from another input channel e Note If you do not specify a rate at a multiple of the increment NI DAQ will automatically choose the next higher step for you e Note Unlike other converter technologies delta sigma converters must be run continuously and at a minimum clock rate to operate within specifications Although the software will let you use a lower sample rate you must always use a sample rate of at least 1 0 kS s to ensure the accuracy of your data acquisition Synchronizing Multiple Devices The NI 4472 can send or receive the DDS clock signal and the synchronization start signal to or from other NI 4472 devices on the same bus to synchronize data acquisition In a multi device system a master device drives the clock and synchronization signals to other slave or receiving devices UN Caution Do not use 5 TRIG 5 to drive any signals in your system if you are synchronizing multiple NI 4472 for PXI CompactPCI devices The synchronization signal is driven on 5 TRIG 5 so driving other signals on RTSI 5 TRIG 5 could lead to double driving the line which can result in unpredictable behavior and might damage your system NI4472 for PCI In a PCI system any NI 4472 can be the master The master broadcasts the ADC oversample clock to the other NI 4472 devices and synchronizes the start of the acquisition using reserved lines in th
14. filter for each input channel This filter has a cutoff frequency of about 400 kHz 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 In the NI 4472 the analog sampler operates at 64 times the selected sample rate for rates above 51 2 kS s and at 128 times the selected sample rate for rates at and below 51 2 kS s For example if you select a sample rate of 102 4 kS s the ADC operates at 6 5536 MS s 64 x 102 4 kS s The analog sampler is a 1 bit ADC The 1 bit oversampled data that the analog sampler produces is passed on to a digital antialiasing filter that 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 4863 times the sample rate is extremely sharp and the rejection above 0 5465 times the sample rate is greater than 110 dB The output stage of the digital filter resamples the higher frequency data stream at the output data rate producing 24 bit digital samples 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 64 times the sample rate for sample rates above 51 2 kS s or 128 times the sample rate for sample r
15. of a waveform you might 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 significant 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 sampling at a higher rate Five analog level triggering modes are available as shown in Figures 3 8 through 3 12 You can set lowValue and highValue independently in the software National Instruments Corporation 3 11 NI 4472 User Manual Chapter 3 Device Overview and Theory of Operation In below low level triggering mode shown in Figure 3 8 the trigger is generated when the signal value is less than lowValue highValue is unused lowValue Trigger ce Figure 3 8 Below Low Level Triggering Mode In above high level triggering mode shown in Figure 3 9 the trigger is generated when the signal value is greater than highValue lowValue is unused highValue Trigger Figure 3 9 Above High Level Triggering Mode In inside region triggering mode shown in Figure 3 10 the trigger is generated when the signal value is between lowValue and highValue highValue ___ 4 4 4 tet cot NI es m RE lowValue ceto Vd Rage SES CHI n PR 98
16. reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader 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 mo
17. that plug into the building power system fall into this category The difference in ground potential or common mode voltage between two instruments connected to the same building power system is typically between 1 and 100 mV but the common mode voltage can be much higher if power distribution circuits are not properly connected This difference in ground potential induces currents in the ground system that can cause errors in your measurement For low common mode voltages the resistor on the signal ground has a resistor value of 50 and is usually sufficient to reduce this current to negligible levels but your results can vary depending on the system setup Itis best to use the NI 4472 to acquire data from floating signal sources but you can measure signals from grounded sources if the ground reference of the source does not vary by more than 2 5 V from the ground reference of the NI 4472 National Instruments Corporation 2 7 NI 4472 User Manual Chapter 2 Using Your NI 4472 Generating Onboard Current Excitation with ICP Circuitry Input Coupling NI 4472 User Manual If you attach an ICP type accelerometer or microphone preamplifier to an analog input channel you must enable the ICP circuitry for that channel in order to generate the required excitation current The ICP circuitry of any input channel can be enabled or disabled independently of that of any other input channel When ICP signal conditioning is enabled larg
18. 0 0 60 0 80 0 dB Full Scale i I T T T T 0 5000 10000 15000 20000 25000 30000 35000 40000 45000 51194 Frequency Hz Figure A 5 Spurious Free Dynamic Range at 102 4 kS s National Instruments Corporation A 5 NI 4472 User Manual Appendix A Specifications THD 1 90 dB 20 dBFS lt 100 dB 60 dBFS lt 60 dB IMD i itte tpe lt 100 dB CCIF 14 kHz 15 kHz Crosstalk channel separation fin 0 to 51 2 kHz Between channels 0 and 1 2 and 3 4 and 5 or 6 and 7 Shorted lt 90 dB TKO Joad 32 2 nies lt 80 dB Other channel combinations Shorted lt 100 dB 1 EO lo8d intente lt 90 dB Phase Ilmeatity te lt 0 5 Interchannel phase mismatch lt fin in KHz x 0 018 0 082 Interchannel gain mismatch 0 1dB Onboard Calibration Reference DC level eo Ree es 5 000 V 2 5 mV Temperature coefficient 5 ppm C max Long term stability sess 20 ppm 41 000 h Signal Conditioning Constant current source software enabled ie eter ecce ceste cud 4 mA 5 Compliance 24 V Output impedance gt 250 at 1 kHz Current nOol
19. 11 Device Configuration ISSUE Shree reete retener emen 2 12 Chapter 3 Device Overview and Theory of Operation Functional Overview eres ete e E RR E pe EB tege res 3 1 Connectors ote eR t ee es eu odios vente Oe ae 3 2 Analog Input Signal 3 3 Calibration dime eE EE a PORT ETHER Ee PR Ve e AREE URN 3 4 Antialias Filtering 5 eene eset ne e tre 3 4 National Instruments Corporation Vii NI 4472 User Manual Contents THe ADG n d ae E EE E eed 3 9 NOISE iiit dB GI ER NR ROO I aise standings 3 10 3 11 Deviceand C locks iiie ee i et RR E 3 14 Chapter 4 Calibration Loading Calibration nennen enne rennen ene 4 1 selt Calibration np tereti e i e ee P e REDE 4 2 External CalibfatloTi 2 ete e arn e et e PER e ER 4 2 Traceable Recalibration erret 4 3 Appendix A Specifications Appendix B Technical Support Resources Glossary Index NI 4472 User Manual Viii ni com Getting Started with Your NI 4472 This chapter describes the NI 4472 for PCI and the NI 4472 for PXI CompactPCI lists what you need to get started explains how to unpack your device and describes your programming choices About the NI 4472 The NI 4472 is a high performance high accuracy analog input
20. 8 to 127 with 0 meaning silence See offset binary format G 12 ni com U unbalanced differential input undersampling V Vec VDC VI waveform National Instruments Corporation Glossary an analog input channel consisting of two terminals with different input impedances whose difference is measured In the case of the NI 4472 one terminal is referenced to ground through a resistor See differential input sampling at a rate lower than the Nyquist frequency can cause aliasing volts collector common voltage power supply voltage volts direct current 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 in reference voltage multiple voltage readings taken at a specific sampling rate G 13 NI 4472 User Manual Index A ADC 3 9 to 3 10 aliasing See also antialias filtering caused by clipped or overranged waveform 3 8 to 3 9 definition 3 4 analog function block diagram 3 2 analog input signal connections 3 3 to 3 10 ADC 3 9 to 3 10 analog input stage figure 3 3 antialias filtering 3 4 to 3 9 alias rejection at oversample rate figure 3 8 comparison of clipped signal to proper signal figure 3 9 input frequency response figure 3 6 input freque
21. A D conversion NI 4472 User Manual Glossary FIFO filtering Fin FIR floating signal sources Js G gain grounded measurement system NI 4472 User Manual first in first out memory buffer the first data stored is the first 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 a type of signal conditioning that allows you to attenuate unwanted portions of the signal you are trying to measure input signal frequency finite impulse response a non recursive digital filter with linear phase 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 ba
22. DAQ NI 4472 User Manual Dynamic Signal Acquisition Device for PCI and PXI CompactPCl INSTRUMENTS May 2001 Edition Part Number 322940B 01 NATIONAL Worldwide Technical Support and Product Information ni com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 794 0100 Worldwide Offices Australia 03 9879 5166 Austria 0662 45 79 90 0 Belgium 02 757 00 20 Brazil 011 284 5011 Canada Calgary 403 274 9391 Canada Montreal 514 288 5722 Canada Ottawa 613 233 5949 Canada Qu bec 514 694 8521 Canada Toronto 905 785 0085 China Shanghai 021 6555 7838 China ShenZhen 0755 3904939 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Germany 089 741 31 30 Greece 30 1 42 96 427 Hong Kong 2645 3186 India 91805275406 Israel 03 6120092 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Malaysia 603 9596711 Mexico 5 280 7625 Netherlands 0348 433466 New Zealand 09 914 0488 Norway 32 27 73 00 Poland 0 22 528 94 06 Portugal 351 1 726 9011 Singapore 2265886 Spain 91 640 0085 Sweden 08 587 895 00 Switzerland 056 200 51 51 Taiwan 02 2528 7227 United Kingdom 01635 523545 For further support information see the Technical Support Resources appendix To comment on the documentation send e mail to techpubseni com Copyright 2001 National Instruments Corporation All rights reserved Important Information Warranty T
23. DING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Compliance FCC Canada Radio Frequency Interference Compliance Determining FCC Class The Federal Communications Commission FCC has rules to protect wireless communications from interference The FCC places digital electronics into two classes These classes are known as Class A for use in industrial commercial locations only or Class B for use in residential or commercial locations Depending on where it is operated this product could be subject to restrictions in the FCC rules In Canada the Department of Communications DOC of Industry Canada regulates wireless interference in much the same way Digital electronics emit weak signals during normal operation that can affect radio television or other wireless products By examining the product you purchased you can determine the FCC Class and therefore which of the two FCC DOC Warnings apply in the following sections Some products may not be labeled at all for FCC if so the reader should then assume these are Class A devices FCC Class A products only display a simple warning statement of one paragraph in length regarding interference and undesired operation Most of our products are FCC Class A The FCC rules have restrictions regarding the locations where FCC Class A products can be operated FCC Class B products display either a FCC ID code starting with the letter
24. Hz to the Nyquist frequency If for instance the sample rate is 50 kS s and a signal component lies within 25 kHz of 6 4 MHz 128 x 50 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 response of the filter is optimized to produce good high frequency alias rejection while having a flat in band frequency response Because this filter is second order its roll off is rather slow The filter has good alias rejection at high sample rates but as a result of its slow roll off does not filter aliases as well at lower sample rates The alias rejection near 64 or 128 times the sample rate versus sample rate for the NI 4472 is illustrated in Figure 3 6 For frequencies not near multiples of the oversample rate the rejection is better than 110 dB National Instruments Corporation 3 7 NI 4472 User Manual Chapter 3 Device Overview and Theory of Operation Alias Rejection dB 0 00 10 00 20 00 30 00 40 00 50 00 60 00 70 00 80 00 90 00 100 00 Sample Rate kS s 1 0 Oversample 128 kHz 1 28 MHz 6 4 MHz Frequency
25. Instruments Corporation 3 3 NI 4472 User Manual Chapter 3 Device Overview and Theory of Operation Calibration Antialias Filtering NI 4472 User Manual lt 51 2 kS s This flexibility in sample rates makes the device well suited for a wide variety of applications including audio and vibration analysis The unbalanced differential analog inputs have software selectable AC DC coupling The NI 4472 analog inputs have calibration adjustments Onboard calibration circuits remove the offset and gain errors for each channel For complete calibration instructions refer to Chapter 4 Calibration A sampling system such as an ADC can represent signals of only limited bandwidth Specifically a sampling rate of f can only represent signals with a maximum frequency of f 2 This maximum frequency is known as the Nyquist frequency The bandwidth from 0 Hz to the Nyquist frequency is the Nyquist bandwidth If a signal is input to the sampling system with frequency components that exceed the Nyquist frequency the sampler cannot distinguish these parts of the signal from some signals with frequency components less than the Nyquist frequency For example suppose a sampler such as an ADC is sampling at 1 000 S s If a 400 Hz sine wave is input then 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 ex
26. NI 4472 User Manual Transfer Characteristics Offset residual DC 3 mV max Gain amplitude accuracy 0 1 dB max fi 1 kHz Amplifier Characteristics Input impedance ground referenced Positive input sees 1 MQ in parallel with 60 pF Negative input shield 50 Q in parallel with 0 02 uF Flatness relative to 1 2 0 03 dB DC to 0 4535 max DC coupled 3 dB bandwidth 0 4863 f Input coupling eee AC or DC software selectable AC 3 dB cutoff frequency 3 4 Hz Overvoltage protection 424 V Negative input shield Not protected Inputs protected CH lt 0 7 gt Common mode rejection ratio CMRR Jin S Y KHz iate gt 60 dB min INOISG 4 4 aper ph e e dede Refer to Figures A 1 through A 3 A 2 ni com Appendix A Specifications 99 00 100 00 101 00 102 00 103 00 104 00 105 00 106 00 107 00 108 00 109 00 110 00 111 00 112 00 113 00 114 00 Noise dB Full Scale 1 0 10 0 512 1000 1000 0 Sample Rate kS s NOTE The change in the noise level at 51 2 kS s is due to the reduction of the oversampling rate of the delta sigma ADC Fig
27. OMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTRONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISUSES OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCLUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS BECAUSE EACH END USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION INCLU
28. Q device samples an analog signal the clock that counts the output of the channel clock in other words the number of samples taken On devices 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 a common ground a property of a DSA device 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 manipulation of signals to prepare them for digitizing a type of coaxial connector 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 system timing controller NI 4472 User Manual Glossary switchless device synchronous system noise THD THD N transducer transfer rate TRIGI EXT TRIG trigger tri state TTL TTL compatible two s complement format NI 4472 User Manual devices that do not require dip switches or jumpers to configure resources on the devices also called Plug and Play devices 1 hardw
29. a sine wave has an RMS magnitude of 8 388 608 1 414 5 932 537 482 least significant bits LSBs Several factors can degrade the noise performance of the inputs One of these factors is noise picked up from nearby electronic devices The NI 4472 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 Refer to the Field Wiring Considerations section of Chapter 2 Using Your NI 4472 for more information One way to reduce the effects of noise on your measurements is to choose the sample rate carefully Take advantage of the anti alias 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 10 kHz for example the anti alias 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 is between roughly 21 6 and 28 kS s 3 10 ni com Trigger Chapter 3 Device Overview and Theory of Operation In addition to supporting internal software triggering and external digital triggering to initiate a
30. are 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 grounded 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 See sensor 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 trigger 1 signal any event that causes or starts some form of data capture logic circuitry designed to have three possible outputs 0O 1 and hi Z The hi Z high impedance state effectively pulls the output out of its circuit and can be used to simplify bus communication by wire ANDing tri state inputs transistor transistor logic operating in a nominal range of 0 to 5 VDC with a signal below 1 V alogic low and a signal above 2 4 V a logic high a system for digitally encoding sound that stores the amplitude values as a signed number with silence represented by a sample with a value of 0 For example with 8 bit sound samples two s complement values would range from 12
31. ates at or below 51 2 kS s The analog filter in each channel rejects possible aliases mostly noise from signals that lie near these multiples Figures 3 4 and 3 5 show the frequency response of the NI 4472 input circuitry National Instruments Corporation 3 5 NI 4472 User Manual Chapter 3 Device Overview and Theory of Operation Amplitude dB 0 00 N 20 00 40 00 60 00 80 00 100 00 120 00 P hace P cn 0 00 0 20 0 40 0 60 0 80 1 00 Frequency Sample Rate f Figure 3 4 Input Frequency Response 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 48 0 49 0 50 Frequency Sample Rate f Figure 3 5 Input Frequency Response Near the Cutoff NI 4472 User Manual 3 6 ni com Chapter 3 Device Overview and Theory of Operation Because the ADC samples at 64 or 128 times the data rate frequency components above one half of the oversampling rate 32 or 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 integer multiples of the oversampling rate 64 for f gt 51 2 kS s 128 and 256 times the data rate and so on because it cannot distinguish these components from components in the baseband 0
32. cation uses the NI DAQ driver software as illustrated in Figure 1 1 1 4 ni com Chapter 1 Getting Started with Your NI 4472 Conventional LabVIEW or Programming Environment Measurement Studio Visual Basic Visual C NI DAQ Driver Software ZN ZEE Computer or Personal Hardware Workstation Figure 1 1 The Relationship Between the Programming Environment NI DAQ and Your Hardware To download a free copy of the most recent version of NI DAQ click Download Software at ni com Using PXI with CompactPCI Using PXI compatible products with standard CompactPCI products is an important feature provided by the PXI Specification Revision 2 0 If you use a PXI compatible plug in device in a standard CompactPCI chassis you will be unable to use PXI specific functions but you can still use the basic plug in device functions For example the RTSI bus on your NI 4472 for PXI CompactPCl is available in a PXI chassis but not in a CompactPCI chassis 5 Note The CompactPCI specification does not require the chassis to supply 3 3 to the devices but the NI 4472 for PXI CompactPCI requires 3 3 V power on the PCI bus in order to work Refer to Appendix A Specifications for complete power requirements National Instruments Corporation 1 5 NI 4472 User Manual Chapter 1 Getting Started with Your NI 4472 The CompactPCI specification permits vendors to deve
33. ceeds 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 as follows 2 325 2 1 000 325 Hz If a 3 975 Hz sine wave is input its apparent frequency is as follows 4 1 000 3 975 25 Hz The process by which the sampler modulates these higher frequency signals back into the 0 to 500 Hz baseband is called aliasing 3 4 ni com Chapter 3 Device Overview and Theory of Operation If the signal in the previous example is not a pure 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 To avoid this it is important to input to the sampler only those signals that can be accurately represented those whose frequency components all 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 4472 includes a two pole anti alias lowpass
34. correct the interference at his own expense Canadian Department of Communications This Class A digital apparatus meets all requirements of the Canadian Interference Causing Equipment Regulations Cet appareil num rique de la classe A respecte toutes les exigences du R glement sur le mat riel brouilleur du Canada Class B Federal Communications Commission This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or television reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures Reorient or relocate the receiving antenna Increase the separation between the equipment and receiver Connect the equipment into an outlet on a circuit different from that to which the receiver is connected Consult the dealer or an experienced radio TV technician for help Canadian Department of Communicatio
35. d Theory of Operation 9 EXT Digital Trigger To 9 lr AC DC 4 Hardware Linear FIFO CHO MUX Coupling LP Filter ADCO Parallel Correction To x AC DC Hardware Linear FIFO CH1 MUX Coupling Peeler ADGA Parallel Correction e e e e e e e To To To lt 0 6 CH 0 6 CH 0 6 lt 0 6 gt CH7 INPUT CAL LP Filter ADC7 Serial IO Hardware Linear MUX Hy Parallel Correction v cone Sone From DDS Correction Trigger Digital cone Control Sone Control Control Overrange Figure 3 2 Analog Function Block Diagram 1 0 Connectors Caution Connections that exceed any of the maximum ratings for input signals on the NI 4472 can damage the device the computer and the associated accessories National Instruments is not liable for any damage resulting from such signal connections The front panel of the NI 4472 has nine SMB male connectors for attaching signal inputs The EXT TRIG connector is the input for the PFIO EXT_TRIG signal Triggers cannot be output from the EXT TRIG connector The EXT TRIG line is compatible with TTL and CMOS voltage levels CH lt 0 7 gt are analog input channels 0 through 7 Input impedance on the positive signal wire of each input channel is 1 MQ in parallel with 60 pF to ground Input impedance on the negative shield wire is 50 Q in parallel with
36. device for the PCI PXI or CompactPCI bus It is part of the National Instruments Dynamic Signal Acquisition Analysis DSA product family and is specifically designed for demanding dynamic signal acquisition applications The NI 4472 features eight analog input channels These channels are simultaneously sampled at a maximum rate of 102 4 kS s with 24 bit resolution and multiple triggering modes including external digital triggering Each input channel has an independent software switchable 4 mA current source for Integrated Circuit Piezoelectric ICP9 type accelerometers and microphone preamplifiers See Appendix A Specifications for details about your NI 4472 The analog input circuitry uses oversampling delta sigma modulating analog to digital converters ADCs Delta sigma converters are inherently linear provide built in brick wall anti aliasing filters and have specifications that exceed other conventional technology for this application with regard to total harmonic distortion THD signal to noise ratio SNR and amplitude flatness These features help you acquire signals with high accuracy and high fidelity without introducing noise or out of band aliases Applications for NI 4472 devices 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 National Instrument
37. dification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright 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 Trademarks DAQPad DAQ STC LabVIEW Measurement Studio MITE National Instruments NI ni com NI DAQ PXI RTSI and SCXI are trademarks of National Instruments Corporation ICP is a registered trademark of PCB Piezotronics Inc Other product and company names mentioned herein are trademarks or trade names of their respective companies WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS 1 NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN 2 IN ANY APPLICATION INCLUDING THE ABOVE RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY C
38. e DC offset voltages can occur on signal inputs due to the output bias voltage requirements of the ICP transducer you are using To remove this offset you must enable AC coupling on the affected input channels of the NI 4472 Using DC coupling with ICP is appropriate only if the impedance of the sensor does not exceed 2 5 kQ and you are acquiring very low frequency signals In LabVIEW use AI Parameter vi to control the onboard excitation You can control onboard excitation only for the channels that are configured for an acquisition in AI Config vi If you are programming in the NI DAQ text application program interface API you should use the AI Change Parameter function with the ND DS A EXCITATION parameter You can configure each analog input channel of the NI 4472 to be AC or DC coupled If you select DC coupling any DC offset present in the source signal is passed to the ADC The DC coupled configuration is usually best 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 bias voltage you must select 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 approximate
39. e RTSI cable For specific LabVIEW programming instructions refer to Synchronizing Multiple PCI DSA Devices in LabVIEW Help Start Programs National Instruments LabVIEW 6 LabVIEW Help For using NI DAQ with National Instruments Corporation 2 11 NI 4472 User Manual Chapter 2 Using Your NI 4472 other ADEs refer to Synchronizing Multiple PCI DSA Devices Select Signal in NI DAQ Function Reference Help Start Programs National Instruments DAQ NI DA Q Help NI4472 for PXI CompactPCI To synchronize two or more NI 4472 devices in a PXI CompactPCI system one must be located in PXI Slot 2 This device is the master and the NI 4472 devices in other slots are slaves The master broadcasts the ADC oversample clock to the other NI 4472 devices on the PXI Star trigger lines and uses the RTSI 5 TRIG 5 line to synchronize the start of the acquisition For specific LabVIEW programming instructions refer to Synchronizing Multiple PXI DSA Devices in LabVIEW Help Start Programs National Instruments LabVIEW 6 LabVIEW Help For using NI DAQ with other ADEs refer to Synchronizing Multiple PXI DSA Devices Select Signal in NI DAQ Function Reference Help Start Programs National Instruments DA Q NI DAQ Help Device Configuration Issues Selecting a sample rate that is less than two times the frequency of a band of interest can lead you to believe the device is functioning improperly By undersampling the signal yo
40. e rejection ratio a measure of an instrument s ability to reject interference from a common mode signal usually expressed in decibels dB 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 a method of triggering in which you simulate an analog trigger using software Also called software triggering 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 ability of a DAQ device to supply current for analog or digital output signals NI 4472 User Manual Glossary DAQ dB dBFS DC DC coupled DDS clock default setting delta sigma modulating ADC device differential input NI 4472 User Manual data acquisition 1 collecting and measuring electrical signals 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 devices plugged into a computer and possibly generating control signals with D A and or DIO devices in the same computer decibel the unit for expressing a logarithmic measure of the ratio of two signal levels dB 20100
41. ebsite lists the DoCs by product family Select the appropriate product family followed by your product and a link to the DoC in Adobe Acrobat format appears Click the Acrobat icon to download or read the DoC 1 Category I refers to equipment for which measures are taken to limit transient overvoltages to a level lower than that of local level mains supplies such as telecommunications and protected electronic circuits National Instruments Corporation A 9 NI 4472 User Manual Technical Support Resources Web Support National Instruments Web support is your first stop for help in solving installation configuration and application problems and questions Online problem solving and diagnostic resources include frequently asked questions knowledge bases product specific troubleshooting wizards manuals drivers software updates and more Web support is available through the Technical Support section of ni com NI Developer Zone The NI Developer Zone at ni com zone is the essential resource for building measurement and automation systems At the NI Developer Zone you can easily access the latest example programs system configurators tutorials technical news as well as a community of developers ready to share their own techniques Customer Education National Instruments provides a number of alternatives to satisfy your training needs from self paced tutorials videos and interactive CDs to instructo
42. ed data transfers over the PCI bus million samples most significant bit normally closed or not connected National Instruments driver software for DAQ hardware G 8 ni com noise nonreferenced signal sources Nyquist frequency Nyquist Sampling Theorem 0 offset binary format operating system oversampling P passband PCI PFI National Instruments Corporation G 9 Glossary 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 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 a frequency that is one half the sampling rate See Nyquist Sampling Theorem the theorem states that if a continuous bandwidth limited analog signal contains no frequency components higher than half the frequency at which it is sampled then the original signal can be recovered without distortion a method of digitally encoding sound that represents the range of amplitude values as an unsigned number with the midpoint of the range
43. ents application software 1 3 to 1 4 NI 4472 See also theory of operation block diagrams analog function block diagram 3 2 digital function block diagram 3 1 front panel figure 2 5 installation hardware installation 2 1 to 2 3 software installation 2 1 J2 connector pins table 1 6 overview 1 1 requirements for getting started 1 2 safety information 1 7 software programming choices National Instruments application software 1 3 to 1 4 NI DAQ driver software 1 4 to 1 5 specifications 1 to 9 unpacking 1 3 using PXI with CompactPCI 1 5 to 1 6 NI Developer Zone B 1 NI DAQ driver software 1 4 to 1 5 noise field wiring considerations 2 10 methods for reducing 3 10 minimizing note 2 4 Nyquist bandwidth 3 4 Nyquist frequency 3 4 0 onboard calibration reference specifications A 6 onboard current excitation generating with ICP circuitry 2 8 operation of NI 4472 See theory of operation overranged waveform 3 8 to 3 9 National Instruments Corporation l 3 Index P PCI See CompactPCI physical specifications A 8 polarity and range 2 9 power requirements A 7 PXI clocks timebases 3 14 installing NI 4472 for PXI CompactPCI note 2 2 using with CompactPCI 1 5 to 1 6 R requirements for getting started 1 2 RSTI 5 TRIG 5 signal for synchronization caution 2 11 S safety information 1 7 safety specifications A 9 sample clock frequency selecting 2 11 synchronizing mul
44. environment that features interactive graphics and the LabWindows CVI Data Acquisition and Easy I O libraries For Visual Basic developers National Instruments Corporation 1 8 NI 4472 User Manual Chapter 1 Getting Started with Your NI 4472 NI DAQ NI 4472 User Manual Measurement Studio features a set of ActiveX controls for using National Instruments DAQ hardware These ActiveX controls provide a high level programming interface for building virtual instruments For Visual C developers Measurement Studio offers a set of Visual C classes and tools to integrate those classes into Visual C applications The libraries ActiveX controls and classes are available with Measurement Studio and the NI DAQ software Using LabVIEW or Measurement Studio software greatly reduces the development time for your data acquisition and control application NI DAQ which shipped with your NI 4472 device has an extensive library of functions that you can call from your ADE These functions allow you to use all the features of your NI 4472 NI DAQ controls all direct interactions between the NI 4472 hardware and the host computer These functions include interrupt programming and direct memory access DMA NI DAQ maintains a consistent software interface among its different versions so that you can change platforms with minimal modifications to your code Whether you are using LabVIEW Measurement Studio or other programming languages your appli
45. ernal DDS timebase or a timebase received from another NI 4472 over the PXI backplane If you configure the NI 4472 to use the internal timebase and place the NI 4472 in slot 2 you can program the device to drive its internal timebase over the PXI backplane to another NI 4472 that you program to receive this timebase signal The default configuration at startup is to use the internal timebase without driving the PXI backplane timebase signal This timebase is software selectable NI 4472 for PCI The NI 4472 for PCI can use either its internal DDS timebase or a timebase received over the RTSI bus If you configure the NI 4472 to use the internal timebase you can program the NI 4472 to drive its internal timebase over the RTSI bus to another NI 4472 that you program to receive this timebase signal The default configuration at startup is to use the internal timebase without driving the RTSI bus timebase signal This timebase is software selectable 3 14 ni com Calibration This chapter discusses the calibration procedures for your NI 4472 Your NI 4472 comes with a calibration certificate The certificate contains a unique tracking number linking your device to the National Instruments corporate databases where the traceability information is stored Calibration refers to the process of minimizing measurement and output voltage errors by making small circuit adjustments On the NI 4472 devices these adjustments are made to the digita
46. g Using Test Panels to Acquire a Signal To quickly test your signal connections and the operation of your system you can use the Test Panels to view a signal input to your NI 4472 To do so follow these instructions 1 Connect a known signal to an analog input channel on the NI 4472 2 Launch Measurement amp Automation Explorer MAX from the desktop Open the Devices and Interfaces folder 4 Right click the icon for the NI 4472 device you want to test and select Test Panel from the pop up menu National Instruments Corporation 2 9 NI 4472 User Manual Chapter 2 Using Your NI 4472 5 Set your parameters as follows e Channel Select the input channel you are using e Sample Rate Hz Enter a sampling rate that is at least twice the highest frequency component of your input signal Data Mode Select Continuous e Y Scale Mode Select Auto Scale 6 Click Start to begin a continuous signal acquisition The Test Panel window displays a graph of the signal you input Field Wiring Considerations Environmental noise can affect the accuracy of measurements made with your NI 4472 if you do not take proper care when running signal wires between signal sources and the device For more information refer to National Instruments Application Note 025 Field Wiring and Noise Considerations for Analog Signals The following recommendations apply mainly to analog input signal routing to the NI 4472 althou
47. gger A 7 digital trigger A 7 synchronizing multiple devices 2 11 to 2 12 system integration by National Instruments B 1 NI 4472 User Manual 1 4 technical support resources B 1 to B 2 test panels for acquiring signals 2 9 to 2 10 testing device configuration 2 3 theory of operation analog input signal connections 3 3 to 3 10 ADC 3 9 to 3 10 analog input stage figure 3 3 antialias filtering 3 4 to 3 9 calibration 3 4 noise 3 10 block diagrams analog function block diagram 3 2 digital function block diagram 3 1 connectors 3 2 to 3 3 triggers 3 11 to 3 14 above high level triggering mode figure 3 12 below low level triggering mode figure 3 12 device and clocks 3 14 high hysteresis triggering mode figure 3 13 inside region triggering mode figure 3 12 low hysteresis triggering mode figure 3 13 timebases 3 14 traceable calibration 4 3 triggers 3 11 to 3 14 above high level triggering mode figure 3 12 below low level triggering mode figure 3 12 device and clocks 3 14 digital trigger 2 9 high hysteresis triggering mode figure 3 13 ni com Index inside region triggering mode U oe a unpacking NI 4472 1 3 low hysteresis triggering mode figure 3 13 specifications W analog trigger B Web support from National Instruments B 1 DIEA Meenas Worldwide technical support B 2 National Instruments Corporation 1 5 NI 4472 User Manual
48. gh they also apply to signal routing in general Minimize noise pickup and maximize measurement accuracy by taking the following precautions NI 4472 User Manual Route signals to the device carefully Keep cabling away from noise sources The most common noise source in a data acquisition system is the video monitor Separate the monitor from the analog signals as much as possible Separate NI 4472 signal lines from high current or high voltage lines These lines can induce currents in or voltages on the NI 4472 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 dedicated metal conduits 2 10 ni com Chapter 2 Using Your NI 4472 Selecting Your Sample Clock Frequency The eight analog input channels of the NI 4472 are simultaneously sampled at any software programmable rate from 102 4 kS s down to 1 0 kS s in 190 7 uS s increments for gt 51 2 kS s or 95 37 uS s increments for fg lt 51 2 kS s The device uses direct digital synthesis DDS technology so that you can choose the correct sample rate for your application All the input channels acquire
49. h the NI 4472 device can come in contact Connections including power signals to ground and vice versa that exceed any of the maximum signal ratings on the NI 4472 device can create a shock or fire hazard or can damage any or all of the boards connected to the chassis the host computer and the NI 4472 device National Instruments is not liable for any damages or injuries resulting from incorrect signal connections Clean the device and accessories by brushing off light dust with a soft non metallic brush Remove other contaminants with a stiff non metallic brush The unit must be completely dry and free from contaminants before returning it to service National Instruments Corporation 1 7 NI 4472 User Manual Using Your NI 4472 This chapter explains how to install configure and test your NI 4472 It also provides information you need to know to acquire signals with your NI 4472 Installing Your Software Complete the following steps in order to install your software before installing your NI 4472 device 1 Install your ADE such as LabVIEW or Measurement Studio according to the instructions on the CD and the release notes 2 Install NI DAQ according to the instructions on the CD and the DAQ Quick Start Guide included with your device hy Note It is important to install the NI DAQ driver software before installing your NI 4472 device to ensure that the device is properly detected Installing Your Hardware
50. he NI 4472 for PCI and the NI 4472 for PXI CompactPCI are warranted against defects in materials and workmanship for a period of one year from the date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace equipment that proves to be defective during the warranty period This warranty includes parts and labor 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 document is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments
51. io inches 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 measured resistance and capacitance between the input terminals of a circuit and ground a computer signal indicating that the CPU should suspend its current task to service a designated activity interrupt request NI 4472 User Manual Glossary kS L LabVIEW library linearity LSB memory buffer MITE MS MSB NC NI DAQ NI 4472 User Manual kilo the standard metric prefix for 1 000 or 103 used with units of measure such as volts hertz and meters 1 000 samples laboratory virtual instrument engineering workbench a file containing compiled object modules each comprised of one of more functions that can be linked to other object modules that make use of these functions nidaqmsc 1ib 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 least significant bit See buffer MXI Interface to Everything a custom ASIC designed by National Instruments that implements the PCI bus interface The MITE supports bus mastering for high spe
52. itions are met the sample includes the data leading up to the trigger condition 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 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 the difference in time between the 1096 and 9096 points of the step response of a system root mean square the square root of the average value of the square of the instantaneous signal amplitude a measure of signal amplitude G 10 ni com RSE RTSI bus S s sample counter SE self calibrating sensor signal conditioning SMB SNR software trigger software triggering STC National Instruments Corporation G 11 Glossary See SE real time system integration bus the National Instruments timing bus that connects DAQ devices directly by means of connectors on top of the devices for precise synchronization of functions seconds samples samples per second used to express the rate at which a DA
53. l 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 It is important to tie the ground reference of a floating signal to the analog input ground to establish a local reference for the signal Otherwise the measured input signal varies as the source floats out of the common mode input range With the NI 4472 you tie the signal ground to the analog input ground simply by attaching the signal cable to any of the analog input channel SMB connectors Hence all floating signals fed to the NI 4472 are automatically ground referenced 5 Note ensure a good ground connection securely fasten the front panel of NI 4472 to the chassis with the screw that held the slot cover NI 4472 for PCI or two screws attached for that purpose NI 4472 for PXI CompactPCI Grounded 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 4472 assuming the PCI bus computer or PXI or CompactPCI chassis and controller are plugged into the same power system Nonisolated outputs of instruments and devices
54. l data coming from the ADCs If you are using the NI DAQ device driver the software includes calibration functions for performing all of the steps in the calibration process Some form of device calibration is required for all but the most forgiving applications If you do not calibrate your device 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 complex and most accurate Loading Calibration Constants Your NI 4472 device is factory calibrated at approximately 25 C to the levels indicated in Appendix A Specifications Before shipment the associated calibration constants the values that were written to the calibration circuitry to achieve calibration in the factory are stored in the onboard nonvolatile memory EEPROM Because the calibration circuits have no memory they do not retain calibration information when the device is unpowered Loading calibration constants refers to the process of loading the calibration circuits with the values stored in the EEPROM NI DAQ determines when this is necessary and does it automatically National Instruments Corporation 4 1 NI 4472 User Manual Chapter 4 Calibration Self Calibration Your NI 4472 can measure and correct almost all of its calibration related errors without any externa
55. l signal connections Your National Instruments software provides a self calibration method Initiate self calibration by calling the DSA Calibrate vi or the Calibrate_DSA function This self calibration process which generally takes less than a minute is the preferred method of assuring accuracy in your application Initiate self calibration to minimize the effects of any offset and gain drifts particularly those due to temperature variations Your NI 4472 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 or during an external calibration operation 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 External Calibration section If you are interested primarily in relative measurements you can ignore a small amount of gain error and self calibration should be sufficient External Calibration NI 4472 User Manual The onboard calibration reference voltage is stable enough for most applications but if you are using your device at an extreme temperature or if the onboard reference has not been measured for two years or more you might want to externall
56. lies only to that platform Contents Chapter 1 Getting Started with Your NI 4472 Abouttlie NE44172 saisir etr A taeda a AA sue eee 1 1 What You Need to Get Started oo eee ce a akea a aaar a a 1 2 Unpacking 5 ccrto tee ete om eei ere ee ier 1 3 Software Programming Choices sees enne 1 3 National Instruments Application Software sese 1 3 NEDA Q Epi eoe a e ENEMIES 1 4 Using PXT witb CompactPCL 5 4 tee E PR dh 1 5 Safety Information eot EAE tdi e Eger 1 7 Chapter 2 Using Your NI 4472 Instalhng Y otr Software ertet teta ee n ceeds Un ett e ett 2 1 Installing Your Hardware deceret ER RE Ee RUE Reve eese dh 2 1 Testing Your Device etate d ee Ee e det Re ede eed us 2 3 Connecting Sign ls ccc eere tette Het ec d a eie e oe aet TEE 2 4 Signal Sources zi ates duet e oq ERR 2 6 Floating Signal Sources sese 2 7 Grounded Signal Sources eee 2 7 Generating Onboard Current Excitation with ICP 2 8 Input Couplings 5 neret en eg addere 2 8 Input Polarity and Input Range 2 9 Digital Trip Ser isn utet Govern RH 2 9 Using Test Panels to Acquire a 1 2 9 Field Waring Considerations rd aret tne d 2 10 Selecting Your Sample Clock Frequency eene 2 11 Synchronizing Multiple Devices serere 2
57. lop sub buses that coexist with the basic PCI interface on the CompactPCI bus Compatible operation is not guaranteed between CompactPCI devices with different sub buses nor between CompactPCI devices with sub buses and PXI The standard implementation for CompactPCI does not include these sub buses Your NI 4472 for PXI CompactPCI will work in any standard CompactPCI chassis adhering to the PICMG CompactPCI 2 0 R2 1 specification Caution Damage to your equipment can occur if the lines shown in Table 1 1 are driven by a CompactPCI sub bus PXI specific features are implemented on the J2 connector of the CompactPCI bus Table 1 1 lists the J2 pins used by your NI 4472 for PXI CompactPCI Your PXI device is compatible with any CompactPCI chassis with a sub bus that does not drive these lines Even if the sub bus is capable of driving these lines the PXI device is still compatible as long as those pins on the sub bus are disabled by default and not ever enabled Damage may result if these lines are driven by the sub bus Table 1 1 J2 Connector Pins Used by the NI 4472 for PXI CompactPCI NI 4472 for PXI CompactPCI Signal PXI Pin Name PXI J2 Pin Number Master Clock Distribution LBL lt 0 12 gt C20 E20 A19 C19 D19 E19 D15 D2 E2 Al CL D1 El Sync Pulse PXI Trigger 5 C18 Reserved LBR O0 12 A21 C21 D21 E21 A20 B20 E15 A3 C3 D3 E3 A2 B2 Master Clock Reception PXI Star In D17 In some circums
58. ly 70 5 Hz 2 8 ni com Chapter 2 Using Your NI 4472 Input Polarity and Input Range The NI 4472 analog inputs are bipolar that is the input voltage range is centered on 0 V The input voltage range is 10 V with 1 19 uV resolution and is always at a gain of 1 0 0 dB Due to the large dynamic range of the ADC used on the NI 4472 programmable gain is not required for most applications Since the NI 4472 does not have hardware to adjust the input gain the component count in the input signal path is reduced resulting in a cleaner signal If the input signal has an amplitude greater than 10 V it will be clipped and introduce large errors that can be easily identified in the frequency spectrum UN Caution Connections that exceed the rated input voltages can damage the computer and the connected equipment Overvoltage protection is 42 2 V on the positive signal line The shield does not have overvoltage protection Do not make a non ground connection to the shield Also do not connect the shield to a ground that varies more than 2 5 V from the ground of the NI 4472 National Instruments is not liable for any damages resulting from such connections All data read from the ADC is interpreted as two s complement format In two s complement mode digital data values read from the analog input channel are either positive or negative Digital Trigger You can use the EXT TRIG SMB connector on the NI 4472 for external digital triggerin
59. mount of random noise to the signal so that the resulting quantization noise although large is restricted to frequencies above 25 6 kHz This noise is not correlated with the input signal and is almost completely rejected by the digital filter National Instruments Corporation 3 9 NI 4472 User Manual Chapter 3 Device Overview and Theory of Operation Noise NI 4472 User Manual The resulting output of the filter is a band limited signal with a dynamic range of 102 4 kS s down to 1 0 kS s in 190 7 uS s increments for fs gt 51 2 kS s or 95 37 uS s increments for fs 51 2 kS s One of the advantages of a delta sigma ADC is that it uses a 1 bit DAC as an internal reference 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 are directly affected by converter DNL The NI 4472 analog inputs typically have a dynamic range of more than 102 4 kS s down to 1 0 kS s in 190 7 uS s increments for f gt 51 2 kS s or 95 37 uS s increments for 51 2 kS s The dynamic range of a circuit is the ratio of the magnitudes of the largest signal the circuit can carry to the residual noise in the absence of a signal In a 24 bit system the largest signal is taken to be a full scale sine wave that peaks at the codes 8 388 607 and 8 388 608 Such
60. n Please contact National Instruments for approved third party calibration service providers Calibration documentation and function libraries are available online at ni com National Instruments Corporation 4 3 NI 4472 User Manual Specifications This appendix lists the specifications of the NI 4472 These specifications are typical at 25 C unless otherwise noted The system must be allowed to warm up for 15 minutes to achieve the rated accuracy Note sure to keep the filler panels on all unused slots in your chassis or computer to maintain forced air cooling Analog Input Channel Characteristics Number of channels 8 simultaneously sampled Input configuration eee eects Unbalanced differential R sol tion 24 bits nominal Type of ADG ettet Delta sigma Oversampling for sample rate f 1 0 kS s f 51 2 kS s 128 f 51 2 kS s lt f 102 4 KS s 64 f Sample rates f sse 102 4 kS s down to 1 0 kS s in 190 7 uS s increments for fs gt 51 2 kS s or 95 37 uS s increments for f 51 2 kS s Frequency 25 ppm Input signal range 10 Vy FIFO buffer size een 1 024 samples Data transfers eeseeeeeee DMA National Instruments Corporation A 1 NI 4472 User Manual Appendix A Specifications
61. ncy response near cutoff figure 3 6 calibration 3 4 noise 3 10 analog input specifications A 1 to A 6 amplifier characteristics A 2 to A 4 idle channel noise figure A 3 input noise spectral density figures A 3 to A 4 channel characteristics A 1 dynamic characteristics A 4 to A 6 spurious free dynamic range figures 5 transfer characteristics A 2 antialias filtering 3 4 to 3 9 alias rejection at oversample rate figure 3 8 comparison of clipped signal to proper signal figure 3 9 National Instruments Corporation input frequency response figure 3 6 input frequency response near cutoff figure 3 6 B bipolar input 2 9 block diagrams analog function block diagram 3 2 digital function block diagram 3 1 bus interface specifications A 7 calibration 4 1 to 4 3 external calibration 4 2 to 4 3 loading calibration constants 4 1 onboard calibration reference specifications A 6 self calibration 4 2 specifications A 8 traceable calibration 4 3 CH lt 0 7 gt signals 3 2 clipped waveform aliases due to clipping figure 3 9 definition 3 8 clocks device and clocks 3 14 selecting sample clock frequency 2 11 to 2 12 CompactPCI clocks timebases 3 14 installing NI 4472 for PXI CompactPCI note 2 2 using with PXI 1 5 to 1 6 configuration device configuration issues 2 12 testing 2 3 NI 4472 User Manual Index connecting signals See signal connections conventions u
62. ns This Class B digital apparatus meets all requirements of the Canadian Interference Causing Equipment Regulations Cet appareil num rique de la classe B respecte toutes les exigences du R glement sur le mat riel brouilleur du Canada Compliance to EU Directives Readers in the European Union EU must refer to the Manufacturer s Declaration of Conformity DoC for information pertaining to the CE Mark compliance scheme The Manufacturer includes a DoC for most every hardware product except for those bought for OEMs if also available from an original manufacturer that also markets in the EU or where compliance is not required as for electrically benign apparatus or cables To obtain the DoC for this product click Declaration of Conformity at com hardref nsf This website lists the DoCs by product family Select the appropriate product family followed by your product and a link to the DoC appears in Adobe Acrobat format Click the Acrobat icon to download or read the DoC Certain exemptions may apply in the USA see FCC Rules 15 103 Exempted devices and 15 105 c Also available in sections of CFR 47 The CE Mark Declaration of Conformity will contain important supplementary information and instructions for the user or installer Conventions lt gt bold italic monospace platform The following conventions are used in this manual Angle brackets that contain numbers separated by an ellipsis repre
63. ooling all covers and filler panels must be installed The NI 4472 for PCI is now installed NI 4472 for PXI CompactPCI 1 Turn off and unplug your PXI or CompactPCI chassis Note If you are installing more than one NI 4472 device in a PXI or CompactPCI chassis and want to synchronize data acquisition operations between the devices one NI 4472 must be installed in slot 2 Refer to the Synchronizing Multiple Devices section of this chapter for more information 2 Choose an unused PXI or CompactPCI slot in your system Note For maximum performance when using a non PXI chassis install the NI 4472 for PXI CompactPCI in a slot that supports bus arbitration or bus master modules The NI 4472 for PXI CompactPCI contains onboard bus master DMA logic that you can use only if the NI 4472 for PXI CompactPCI is installed in such a slot National Instruments recommendis installing the NI 4472 for PXI CompactPCI in such a slot If you choose a slot that does not support bus masters you will have to disable the onboard DMA controller using your software A PXI compliant chassis must have bus arbitration for all slots Caution The NI 4472 for PXI CompactPCI has connections to several reserved lines on the CompactPCI J2 connector Use of these lines by other devices in your CompactPCI system can damage your equipment Before installing an NI 4472 for PXI CompactPCI in a CompactPCI system that uses J2 connector lines for purposes other than PXI see the
64. r led hands on courses at locations around the world Visit the Customer Education section of ni com for online course schedules syllabi training centers and class registration System Integration If you have time constraints limited in house technical resources or other dilemmas you may prefer to employ consulting or system integration services You can rely on the expertise available through our worldwide network of Alliance Program members To find out more about our Alliance system integration solutions visit the System Integration section of ni com National Instruments Corporation B 1 NI 4472 User Manual Appendix B Technical Support Resources Worldwide Support National Instruments has offices located around the world to help address your support needs You can access our branch office Web sites from the Worldwide Offices section of ni com Branch office Web sites provide up to date contact information support phone numbers e mail addresses and current events If you have searched the technical support resources on our Web site and still cannot find the answers you need contact your local office or National Instruments corporate Phone numbers for our worldwide offices are listed at the front of this manual NI 4472 User Manual B 2 ni com Glossary Prefix Meanings Value p pico 10 12 n nano 10 9 u micro 10 6 m milli 10 3 k kilo 103 M mega 106 N
65. representing silence For example an 8 bit sound stored in offset binary format would contain sample values ranging from 0 to 255 with a value of 128 specifying silence no amplitude See two s complement format base level software that controls a computer runs programs interacts with users and communicates with installed hardware or peripheral devices sampling at a rate greater than the Nyquist frequency the range of frequencies which a device can properly propagate or measure Peripheral Component Interconnect a high performance expansion bus architecture originally developed by Intel to replace 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 programmable function input NI 4472 User Manual Glossary Plug and Play devices port posttriggering ppm pretriggering Q quantization error quantizer R relative accuracy resolution rise time rms NI 4472 User Manual devices that do not require DIP switches or jumpers to configure resources on the devices also called switchless devices a communications connection on a computer or a remote controller the technique used on a DAQ device to acquire a programmed number of samples after trigger conditions are met parts per million the technique used on a DAQ device to keep a continuous buffer filled with data so that when the trigger cond
66. s Corporation 1 1 NI 4472 User Manual Chapter 1 Getting Started with Your NI 4472 What You Need to Get Started To set up and use your NI 4472 device you need the following Q Q One of the following devices 4472 for PCI NI 4472 for PXI CompactPCI NI 4472 User Manual One of the following software packages and documentation LabVIEW Windows Measurement Studio Windows Asupported application development environment such as Visual C NI DAQ for PC Compatibles and documentation Your PCI bus computer or PXI or CompactPCI chassis and controller Female SMB connector cables The following documents also contain information you may find helpful National Instruments Application Note 025 Field Wiring and Noise Considerations for Analog Signals PICMG CompactPCI 2 0 R2 1 PXI Specification Revision 2 0 Your PC reference manual Your PXI CompactPCI chassis technical reference manual For free downloads of the latest documentation drivers and programming examples visit ni com NI 4472 User Manual 1 2 ni com Chapter 1 Getting Started with Your NI 4472 Unpacking Your NI 4472 is shipped in an antistatic plastic package to prevent electrostatic damage to the device Electrostatic discharge can damage several components on the device To avoid such damage when handling the device take the following precautions e Ground yourself with a grounding strap or by touching
67. s EXN Trade Name Number or the FCC Class B compliance mark that appears as shown here on the right Tested to Comply with FCC Standards Consult the FCC web site http www fcc gov for more information FCC DOC Warnings This equipment generates and uses radio frequency energy and if not installed and used in strict accordance with the instructions in this manual and the CE Mark Declaration of Conformity may cause interference to radio and television reception Classification requirements are the same for the Federal Communications Commission FCC and the Canadian Department of Communications DOC FOR HOME OR OFFICE USE Changes or modifications not expressly approved by National Instruments could void the user s authority to operate the equipment under the FCC Rules Class A Federal Communications Commission This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to
68. se cere eek 500 pA Hz Measured with full scale 10 V input NI 4472 User Manual A 6 ni com Triggers Analog Trigger SOUECO er eie Resolution eene Hystetesis eee e ees Digital Trigger Compatibility eee Response Pulse width ceo aede Bus Interface Power Requirements 13 3 VDC NI 4472 for PCI NI 4472 for PXI CompactPCI 5 VDC NI44T2 for PCT NI 4472 for PXI CompactPCI HID N DC intact eres National Instruments Corporation A 7 Appendix A Specifications CH lt 0 7 gt 10 to 10 V full scale programmable Positive or negative software selectable 24 bits nominal Programmable TTL CMOS Rising or falling edge 10 ns min Master slave 0 mA max 400 mA max 2 600 mA max 2 200 mA max 120 mA max 120 mA max NI 4472 User Manual Appendix A Specifications Physical Dimensions not including connectors NI 4472 for PXI CompactPCl NI4472 for PCI Analog I O connectors Digital trigger Environmental Operating temperature Storage UM GY e Calibration Internal anneanne Interval 21 ua tek eS External us Interval t eee ots Warm up time
69. sed in manual vi current excitation generating with ICP circuitry 2 8 customer education B 1 D DDS clock 2 11 3 14 delta sigma modulating ADC converters ADC operation 3 9 to 3 10 overview 1 1 requirements for running note 2 11 2 12 device configuration issues 2 12 digital function block diagram 3 1 digital trigger external digital triggering 2 9 specifications A 7 direct digital synthesis DDS clock 2 11 3 14 E electromagnetic compatibility specifications A 9 environment specifications A 8 excitation of current generating 2 8 EXT TRIG connector 2 9 3 2 external calibration 4 2 to 4 3 F field wiring considerations 2 10 filtering See antialias filtering floating signal sources description 2 7 input configuration figure 2 6 NI 4472 User Manual l 2 G grounded signal sources description 2 7 input configuration figure 2 6 H hardware installation 2 1 to 2 3 ICP circuitry for generating onboard current excitation 2 2 overview 2 2 input coupling 2 8 input polarity and input range 2 9 installation hardware installation 2 1 to 2 3 NI 4472 for PXI CompactPCI note 2 2 software installation 2 1 unpacking NI 4472 1 3 Integrated Circuit Piezoelectric ICP type accelerometers 1 1 connectors 3 2 to 3 3 J J2 connector pins used by NI 4472 table 1 6 L LabVIEW software 1 3 Measurement Studio software 1 3 to 1 4 ni com National Instrum
70. sent a range of values associated with a bit or signal name for example DBIO lt 3 0 gt The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options directs you to pull down the File menu select the Page Setup item and select Options from the last dialog box The symbol indicates that the following text applies only to a specific product a specific operating system or a specific software version This icon denotes a note which alerts you to important information The icon denotes a caution which advises you of precautions to take to avoid injury data loss or a system crash Bold text denotes items that you must select or click on in the software such as menu items and dialog box options Bold text also denotes parameter names Italic text denotes variables emphasis a cross reference or an introduction to a key concept This font also denotes text that is a placeholder for a word or value that you must supply Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions and code excerpts Text in this font denotes a specific platform and indicates that the text following it app
71. tances it is possible to drive some of these lines in the same chassis as your NI 4472 For more information search the NI KnowledgeBase at ni com public NI 4472 User Manual 1 6 ni com Chapter 1 Getting Started with Your NI 4472 Safety Information UN Cautions To meet EMC EMI cooling and safety compliance requirements the NI 4472 device must be installed in a PC with the covers and chassis filler panels properly installed Do not operate the device in an explosive atmosphere or where there may be flammable gases or fumes Do not operate damaged equipment The safety protection features built into the NI 4472 device can become impaired if the device becomes damaged in any way If the device is damaged turn the device off and do not use it until service trained personnel can check its safety If necessary return the device to National Instruments for service and repair to ensure that its safety is not compromised Do not operate this equipment in a manner that contradicts the information specified in this document Misuse of this equipment could result in a shock hazard Do not substitute parts or modify equipment Because of the danger of introducing additional hazards do not install unauthorized parts or modify the NI 4472 device Return the device to National Instruments for service and repair to ensure that its safety features are not compromised You must insulate all of your signal connections to the highest voltage with whic
72. tiple devices 2 11 to 2 12 sample rates selecting 2 11 self calibration 4 2 signal acquisition using test panels 2 9 to 2 10 signal conditioning ICP signal conditioning 2 8 specifications A 6 signal connections 2 4 to 2 9 analog input 3 3 to 3 10 ADC 3 9 to 3 10 analog input stage figure 3 3 antialias filtering 3 4 to 3 9 calibration 3 4 noise 3 10 current excitation generating with ICP circuitry 2 8 NI 4472 User Manual Index digital trigger 2 9 exceeding rated input voltages note 2 9 front panel figure 2 5 input coupling 2 6 input polarity and input range 2 9 connectors 3 2 to 3 3 minimizing noise note 2 4 signal sources 2 6 to 2 7 floating signal sources 2 6 grounded signal sources 2 7 input configurations figure 2 6 signal sources 2 6 to 2 7 floating signal sources 2 7 grounded signal sources 2 7 input configurations figure 2 6 software installation 2 1 software programming choices National Instruments application software 1 3 to 1 4 NI DAQ driver software 1 4 to 1 5 specifications A 1 to A 9 analog input A 1 to A 6 amplifier characteristics A 2 to A 4 channel characteristics A 1 dynamic characteristics A 4 to A 6 transfer characteristics A 2 bus interface A 7 calibration A 8 electromagnetic compatibility A 9 environment A 8 onboard calibration reference A 6 physical A 8 power requirements A 7 safety A 9 signal conditioning A 6 triggers analog tri
73. troller resources from your computer To check the configuration of your NI 4472 and to test its resource allocations to be sure they do not conflict with any others refer to the DAQ Quick Start Guide included with your device You can modify data acquisition related settings such as analog input polarity range and mode through National Instruments application level software such as LabVIEW or Measurement Studio or with NI DAQ Refer to device configuration instructions in your NI DAQ documents and in the NI DAQ Function Reference Help Start Programs National Instruments DA Q NI DA Q Help for more information National Instruments Corporation 2 3 NI 4472 User Manual Chapter 2 Using Your NI 4472 Connecting Signals The front panels of the NI 4472 for PCI and the NI 4472 for PXI CompactPCI are shown in Figure 2 1 The NI 4472 has eight male SMB connectors on its front panel for connecting analog signals and one male SMB connector for connecting a digital trigger The analog inputs are unbalanced differential channels with individually configurable AC DC coupling and ICP type current conditioning The digital input can accept TTL CMOS compatible signals Note To minimize noise and ensure more accurate measurements do not allow the connector shells of your SMB cables SMB to BNC adapters or BNC cables to touch each other the PCI bus computer or the PXI or CompactPCI chassis and controller NI 4472 User Manual 2
74. tteries transformers or thermocouples sampling frequency or rate the factor by which a signal is amplified sometimes expressed in decibels See SE G 6 ni com H h hardware hardware triggering high impedance I O IMD in INL input impedance interrupt IRQ National Instruments Corporation G 7 Glossary hour the physical components of a computer system such as the circuit boards plug in boards chassis enclosures peripherals and cables a form 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 in logic circuits designed to have three possible states O 1 and hi Z the hi Z high impedance state effectively removes the output from its circuit and can be used to simplify bus communication by wire ANDing tri state inputs hertz cycles per second Specifically refers to the repetition frequency of a waveform input output the transfer of data to from a computer system involving communications channels operator interface devices and or data acquisition and control interfaces intermodulation distortion the ratio in dB 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 CCIF A 14 kHz sine wave and a 15 kHz sine wave added in a 1 1 amplitude rat
75. u might 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 simply increase the sample rate until it meets the requirements of the Nyquist Sampling Theorem For more information on the filters and aliasing refer to the Antialias Filtering section of Chapter 3 Device Overview and Theory of Operation aye Note Unlike other converter technologies delta sigma converters must be run continuously and at a minimum clock rate to operate within specifications Although the software will let you use a lower sample rate you must always use a sample rate of at least 1 0 kS s to ensure the accuracy of your data acquisition NI 4472 User Manual 2 12 ni com Device Overview and Theory of Operation This chapter presents an overview of the hardware functions of your NI 4472 and other useful information for understanding how the device works Functional Overview Figure 3 1 shows a block diagram of the digital functions and the analog function block diagram is shown in Figure 3 2 Mini MITE PCI Controller DMA Control Synchronization 2 a O Clock Control General Control a To ADCs DDS Clock Generator Figure 3 1 Digital Function Block Diagram NI 4472 User Manual National Instruments Corporation 3 1 Chapter 3 Device Overview an
76. umbers Symbols 3 degree Q ohm percent positive of or plus negative of or minus per A amperes A D analog to digital AC alternating current AC coupled allowing the transmission of AC signals while blocking DC signals ADC analog to digital converter an electronic device often an integrated circuit that converts an analog voltage to a digital number National Instruments Corporation G 1 NI 4472 User Manual Glossary ADC resolution ADE alias amplification amplitude flatness API asynchronous attenuate bandwidth bipolar buffer bus NI 4472 User Manual the size of the discrete steps in the ADCS input to output transfer function therefore the smallest voltage difference an ADC can discriminate with a single measurement application development environment an application designed to make it easier for you to develop software Usually ADEs have a graphical user interface and programming tools to help with development Examples of ADEs are LabVIEW LabWindows CVI Visual Basic and Visual C a false lower frequency component that appears in sampled data acquired at too low a sampling rate a 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 application program interface 1 hardware a property of an event that occurs at an
77. und whose difference is measured G 4 ni com differential measurement system digital trigger DMA DNL down counter drivers DSA dynamic range E EEPROM event external trigger National Instruments Corporation G 5 Glossary 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 a TTL level signal having two discrete levels a high and a low level 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 differential nonlinearity a measure in LSBs of the worst case deviation 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 device or a GPIB interface device dynamic signal acquisition 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 the condition or state of an analog or digital signal a voltage pulse from an external source that triggers an event such as
78. ure A 1 Idle Channel Noise Spectral Noise Density referred to input 16 384 points 51 2 kS s 10 averages 1 0m V sqrt Hz 10 0 k 25 6 k Frequency Hz Figure A 2 Input Noise Spectral Density at 128 Times Oversampling National Instruments Corporation A 3 NI 4472 User Manual Appendix A Specifications Spectral Noise Density referred to input 16 384 points 102 4 kS s 10 averages 1 0m zx e o o T V sqrt Hz 1 04 100 0 n 10 0 4 Frequency Hz NI 4472 User Manual Figure A 3 Input Noise Spectral Density at 64 Times Oversampling Dynamic Characteristics Alias free bandwidth passband DC 0 Hz to 0 4535 f Stop band aerei 0 5465 f Alias rejection 110 dB Delay through ADC anti aliasing filter 38 8 sample periods Spurious free dynamic range 130 dB 1 0 kS s f 51 2 kS s 118 dB 51 2 kS s f 102 4 kS s A 4 ni com Appendix A Specifications Typical 60 dB FFT 10 averages 16 384 points 51 2 kS s dB Full Scale e 4 o e o 0 2500 5000 7500 10000 12500 15000 17500 20000 22500 25597 Frequency Hz Figure A 4 Spurious Free Dynamic Range at 51 2 kS s Typical 60 dB FFT 10 averages 16 384 points 102 4 kS s 0 0 20 0 4
79. y calibrate your device External calibration refers to calibrating your device with a known external reference rather than relying on the onboard reference The new calibration constants are stored in the onboard EEPROM overwriting the factory calibration constants Externally calibrate your device by calling the DSA Calibrate vi or the Calibrate DSA function When you perform an external calibration be sure to use a very accurate external DC reference The reference should be several times more accurate than the device itself For example to calibrate the NI 4472 the external reference should have a DC accuracy better than 115 ppm 0 001 dB 4 2 ni com Chapter 4 Calibration B Note When you calibrate your NI 4472 make sure that ICP power is turned off to avoid affecting the reference voltage reading Traceable Recalibration Traceable recalibration is divided into three different areas factory on site and third party Devices typically require this type of recalibration every year If you require factory recalibration send your NI 4472 back to National Instruments National Instruments will send the device back to you with a new calibration certificate 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 4472 at your location on site You can also send your NI 4472 to a third party for recalibratio

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