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SCXI-1122 User Manual - National Instruments

1. 1NOY 4 9JoH Bununow jueujeujnsDe N yanng m s osqwunyl 19018 40 SPD JO SISAY puwa M9J9S Buipuno19 10jsiseM LONDIqHDy junys J0100uuoj3 SNGIXDS 000 py air k oooaglooa gi 10 22uu0 eas o a I p 00000 noana Y eM sojoouuoo f AAN LR joubis oy Ris a f 00000 4099 3 estis ped 2211 1195 waliasi Y DELE CE EE CEC ETE ETE LECCE s0s00900002000000025090900 310H Burunow 1 o g puwa LM J9QUINN JOG Jaha UOISIASY PUD i JOQUINN Aiquiessy a MeJosquunu SulDN jonpoud O National Instruments Corporation Figure 2 1 SCXI 1122 Parts Locator Diagram 2 2 SCXI 1122 User Manual Chapter 2 Configuration and Installation Digital Signal Connections Note If nothing is cabled to the SCXI 1122 rear signal connector the position of jumper W2 is irrelevant The SCXI 1122 has one jumper jumper W2 for communication between the DAQ board and the SCXIbus shown in Table 2 1 Table 2 1 Digital Signal Connection Jumper Settings DAQ board to Position 1 pullup Use this setting SCXIbus for a single chassis system communication Connects a 2 2 kQ pullup resistor to the SERDATOUT line factory setting Position 3 unmarked position no pullup Use this setting for additional chassis in a multichassis system No pullup resistor is connected to the SERDATOUT line If a module is not connected to a DAQ board the position of W2 is irrelevant The MISO line on the SCXI 1122 modu
2. 1 Vrms refers to sinusoidal waveform V refers to DC or AC peak National Instruments Corporation A 1 SCXI 1122 User Manual Specifications Transfer Characteristics Nonlinearity Offset error Gain 1 Gain lt 1 Gain error Gain 1 Gain lt 1 Amplifier Characteristics Input impedance Normal powered on Powered off Overload Input bias current CMRR Output range Output impedance Dynamic Characteristics Bandwidth 3 dB Settling time to full scale step all gains with 4 kHz filter enabled with 4 kHz filter enabled System noise Slew rate Filters Type Cutoff frequency 3 dB NMR 50 or 60 Hz Stability Recommended warm up time Offset temperature coefficient Gain temperature coefficient SCXI 1122 User Manual Appendix A 0 01 FSR 6 uV 1 240 n V gain 352 UV 1 240 uV gain 0 02 of reading 0 10 of reading 1 GQ in parallel with 100 pF for gain 2 1 1 MQ in parallel with 100 pF for gain lt 1 100 KQ 100 kQ 80 pA Filter Bandwidth CMRR 50 or 60 Hz 4Hz 160 dB 4 kHz 100 dB 10 V 75 Q 4 Hz 10 dB or 4 kHz software selectable 10 ms 1s 4 Hz Filter 4 kHz Filter 1 150 uVrms 1 mVrms 1 000 1 000 nVrms 4uVrms 0 10 V us 3 pole RC 4 Hz 10 dB or 4 kHz software selectable 60 dB at 4 Hz bandwidth 20 minutes 0 2 150 gain u V C 10 ppm C for gain 2 1 25 ppm C for gain lt 1 A 2 O National Instruments Corporation Appendix A
3. 12 45V CH 13 CH 14 TEMP CH 15 TEMP Figure 3 1 SCXI 1122 Front Connector Pin Assignments O National Instruments Corporation 3 3 SCXI 1122 User Manual Signal Connections Chapter 3 Front Signal Connection Descriptions Pin Al A3 A7 All A13 A15 A17 A19 A2 A23 A5 A9 A25 A29 A3 B32 B2 C31 CI Signal Name TEMP TEMP 5 V VEX 2 VEX SENSE SENSE VEX IEX IEX RSVD CH 0 15 CH 0 15 SCXI 1122 User Manual Description Temperature Sensor Reference This pin is tied to the temperature sensor reference in the terminal block and to the isolation amplifier negative input in the module Temperature Sensor Output This pin connects the temperature sensor output to the amplifier input selector 5 VDC Isolated Source This pin which powers the temperature sensor on the terminal block has 0 5 mA of source not protected Half Voltage Excitation Output This pin connects to the internal bridge completion network for quarter bridge and half bridge measurements Protected to 20 V maximum Negative Voltage Excitation Output This pin is connected to the voltage excitation negative output Negative Voltage Sense This pin must be tied to VEX at the load for remote sensing When using the SCXI 1322 terminal block this pin is connected to VEX SENSE screw terminals Positive Voltage Sense This pin must be tied to VEX at t
4. Excitation Output Characteristics Channels Bridge type Bridge completion Voltage Mode Level Current drive Drift Current Mode Level Max load resistance Drift Physical Dimensions T O connectors Environment Operating temperature Storage temperature Relative humidity Maximum altitude Safety Electrical Measuring and Test Equipment Installation Category Pollution degree O National Instruments Corporation Specifications 2 1 voltage and 1 current Quarter half or full Two 2 5 KQ 0 02 ratio tolerance resistors 3 333 V 0 04 225 mA 30 ppm C 1 0 mA 40 04 5 ka 40 ppm C 3 0 by 17 3 by 20 3 cm 1 2 by 6 8 by 8 0 in 50 pin male ribbon cable rear connector 48 pin male DIN C front I O connector 0 to 50 C 20 to 70 C 10 to 90 lt 2000 meters IEC EN 61010 1 UL 3111 1 CAN CSA C22 2 No 1010 1 Category II 2 A 3 SCXI 1122 User Manual Appendix B Customer Communication For your convenience this appendix contains forms to help you gather the information necessary to help us solve technical problems you might have as well as a form you can use to comment on the product documentation Filling out a copy of the Technical Support Form before contacting National Instruments helps us help you better and faster National Instruments provides comprehensive technical assistance around the world In the U S and Canada applications engineers are available Monday through Friday from 8
5. 0 CH 8 CH 9 CH 1 CH 1 CH 9 CH 15 CH 7 CH 7 CH 15 Any R lt 5kQ Figure 4 3 Four Wire Scan Connection with Multiplexed Current Excitation SCXI 1122 User Manual 4 6 National Instruments Corporation Chapter 4 Theory of Operation Note Always connect the current excitation terminals outside the sense terminals as shown in both Figures 4 2 and 4 3 Each approach has its advantages and disadvantages as listed in Table 4 2 Table 4 2 Pros and Cons of Two Wire and Four Wire Connections Series connection with two wire scanning Independent connection 5 kQ per channel with four wire scanning 250 Vrms CMV between transducers O National Instruments Corporation 4 7 with Current Excited Transducers Limited to 5 kQ total resistance No isolation between channels 16 transducers per module All transducers are continuously excited Two wire connections are easier to connect because of fewer wires Eight transducers maximum per module More connections SCXI 1122 User Manual Chapter 5 Calibration This chapter discusses the calibration procedures for the SCXI 1122 Overview The onboard calibration hardware that calibrates the SCXI 1122 consists of an EEPROM to store the calibration constants and an auto zero channel on the amplifier input selector When the auto zero channel is selected the input relay multiplexer is disconnected from the amplifier inputs and the isolation amplifier inputs ar
6. 00 a m to 6 00 p m central time In other countries contact the nearest branch office You may fax questions to us at any time Corporate Headquarters 512 795 8248 Branch Offices Australia Austria Belgium Brazil Canada Calgary Canada Ontario Canada Qu bec China Denmark Finland France Germany Greece Hong Kong India Israel Italy Japan Korea Mexico D F Mexico Monterrey Netherlands Norway Singapore Spain Barcelona Spain Madrid Sweden Switzerland Taiwan U K Phone Number 03 9879 5166 0662 45 79 90 0 02 757 00 20 011 284 5011 403 274 9391 905 785 0085 514 694 8521 0755 3904939 45 76 26 00 90 725 725 11 1 48 14 24 24 089 741 31 30 30 1 42 96 427 2645 3186 91805275406 03 6120092 02 413091 03 5472 2970 02 596 7456 5 280 7625 8 357 7695 0348 433466 32 27 73 00 2265886 93 582 0251 91 640 0085 08 587 895 00 056 200 51 51 02 2377 1200 0635 523545 O National Instruments Corporation B 1 SCXI 1122 User Manual Technical Support Form Photocopy this form and update it each time you make changes to your software or hardware and use the completed copy of this form as a reference for your current configuration Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently If you are using any National Instruments hardware or software products related to this pro
7. 1122 module and explains the operation of each functional unit making up the SCXI 1122 e Chapter 5 Calibration discusses the calibration procedures for the SCXI 1122 Appendix A Specifications lists the specifications for the SCXI 1122 e Appendix B Customer Communication contains forms you can use to request help from National Instruments or to comment on our products The Glossary contains an alphabetical list and description of terms used in this manual including abbreviations acronyms metric prefixes mnemonics symbols and terms The Index contains an alphabetical list of key terms and topics in this manual including the page where you can find each one O National Instruments Corporation ix SCXI 1122 User Manual About This Manual Conventions Used in This Manual The following conventions are used in this manual A This symbol refers to a caution that must be taken when operating this equipment This symbol is found on the equipment and near the explanation of the caution in the manual bold italic Bold italic text denotes a note caution or warning italic Italic text denotes emphasis a cross reference or an introduction to a key concept Lab board Lab board refers to the Lab LC Lab NB Lab PC and Lab PC boards unless otherwise noted MC MC refers to the Micro Channel series computers MIO board MIO board refers to the National Instruments multichannel I O DAQ boards AT MIO 16 MC MIO 16 AT MIO 16
8. Address Line This signal taps into the SCXTIbus DYA line to indicate to the module whether the incoming serial stream is data or address information Slot 0 Select This signal taps into the SCXIbus INTR line to indicate whether the information on MOSI is being sent to a module or Slot 0 Scan Clock This indicates to the SCXI 1122 that a sample has been taken by the DAQ board and causes the SCXI 1122 to change channels Serial Clock This signal taps into the SCXIbus SPICLK line to clock the data on the MOSI and MISO lines Reserved The signals on the rear signal connector can be classified as analog output signals digital I O signals or timing I O signals Signal connection guidelines for each of these groups are given in the following section Analog Output Signal Connections Pins 1 through 4 and pin 19 of the rear signal connector are analog output signal pins Pins 1 and 2 are AOGND signal pins AOGND is an analog output common signal that is routed through jumper W1 to the analog reference on the SCXI 1122 You can use these pins as a general analog power ground tie point to the SCXI 1122 if necessary O National Instruments Corporation 3 11 SCXI 1122 User Manual Signal Connections Chapter 3 In particular when using differential input DAO boards such as the MIO 16 boards it is preferable to leave jumper W1 in its factory setting or in position AB RI to avoid ground loops With DAQ boards that are configured for refere
9. Digital Signal Connections ies eint eser er taa eo aeo de oo doc a es e Ped cpu praes e des 2 3 TAG SC OMIT OUT OO did id tech satan O ais 2 3 Current Loop RECCIV GIS iiec visae ies teet eee NIE ka 2 4 Hardware Installation ondo 2 6 Chapter 3 Signal ConnectioHs a a e ao e aaa toco o 3 1 As A A 3 3 Front Signal Connection Descriptions esee 3 4 Analog Input Channel Signal Connections esses 3 5 Excitation Channel Signal Connections eee 3 8 KACHA WA aio ed 3 8 Using the Internal Half Bridge Completion 3 9 Temperature Sensor Connection s reci tepnecd ion tea it 3 9 Rear Sie ial COHBOCIOE eee evite Bde di pvo setate eli n dida cu aea ris E 3 10 Rear Signal Connection Descriptions rms iia ene weaves vas 3 11 Analog Output Signal Connections cooocononcccnoncnonnnccnnnnncnoncccnonnccnnnnncnnnos 3 11 Digital I O Signal Connector 3 12 Chapter 4 Theory of Operation ca Doe tetas ete qe Ule et PU nee 4 1 Functional Overview wi aa 4 1 Rear Signal Connector SCXIbus Connector and SCXIbus Interface 4 3 Digital Control Circuitry eui tete ee tee ertt eo ae secede as seneesaa aiiai 4 3 SS eer EE 4 3 Analog Input Chanriels 1 netos te eee toe tenci n pee eh pidan Jaiba 4 3 Excitation Output Channels circuito cios pelao 4 5 O National Instruments Corporation v SCXI 1122 User Manual Contents Chapter 5 Calibration sl AAA T
10. 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 INCLUDING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Contents About This SVE AI A eoo e teet O ix Organzationzok This Manual mosse tede pin edu den su uh at uu d RUE ix Conventions Used in This Manual iu eS X The National Instruments Documentation Set eese xi Related DOC E Ai xi Customer Communicati OM a A TA xii Chapter 1 Introduction aci 1 1 What Your Kit Should Contatn iiusec esie eerte een ene dese a eR Reds es de Pe qd ananena 1 1 Software Programming Choices rodilla Ade er eR RE RUn ope TUER Ene UE MEO Iu Eus 1 2 LabVIEW and LabWindows Application Software sese 1 2 NI DAQ Driver Software eoe tte etre treten err euer etes Peres 1 2 Register Level Programming 5 ose erede eta to een de oo doe a eo aede ana cosets 1 4 Optional Equipment pene e eed eri queue Aa ul eeu 1 4 Custom Cables qe ER 1 5 Unpackiig ese ie lit lso 1 5 Chapter 2 Configuration and Installation sse 2 1 Modulo Contour 2 1
11. address DAQD A 1 information e Pin 29 SLOTOSEL is equivalent to the SCXIbus INTR line It indicates whether the data on the SERDATIN line is being sent to Slot 0 SLOTOSEL 0 or to a module SLOTOSEL 1 Pins 24 and 33 are the digital ground references for the DAQ board digital signals and are tied to the module digital ground e Pin 37 SERCLK is equivalent to the SCXIbus SPICLK line and is used to clock the serial data on the SERDATIN line into the module registers The digital output signal pin 26 is SERDATOUT and is equivalent to SCXIbus MISO The SCXI 1122 digital input and output signals match the digital I O lines of the MIO 16 boards When used with an SCXI 1341 SCXI 1342 or SCXI 1344 cable assembly the SCXI 1122 signals match the digital lines of the Lab NB PC PC the PC LPM 16 and the Lab LC boards respectively Table 3 2 lists the equivalences For more detailed information consult your cable installation guide SCXI 1122 User Manual 3 12 O National Instruments Corporation Chapter 3 Signal Connections Table 3 2 SCXIbus to SCXI 1122 Rear Signal Connector to DAQ Board Pin Eguivalences SCXIbus Line SCXI 1122 MIO 16 Lab Boards PC LPM 16 Rear Signal Connector SERDATIN ADIOO DAQD A ADIOI SLOTOSEL ADIO2 SERCLK EXTSTROBE SERDATOUT BDIOO The digital timing signals are pins 36 43 and 46 e Pin 36 is used as a clock by the SCXI 1122 to increment to the next channel after each convers
12. cable header The manufacturer part number that National Instruments uses for this header is as follows AMP Inc part number 1 103310 0 The mating connector for the SCXI 1122 rear signal connector is a 50 position polarized ribbon socket connector with strain relief National Instruments uses a polarized or keyed connector to prevent inadvertent upside down connection to the SCXI 1122 Recommended manufacturer part numbers for this mating connector are as follows e Electronic Products Division 3M part number 3425 7650 e T amp B Ansley Corporation part number 609 5041CE Standard 50 conductor 28 AWG stranded ribbon cables that you can use with these connectors are as follows Electronic Products Division 3M part number 3365 50 e T amp B Ansley Corporation part number 171 50 The SCXI 1122 front connector is a 48 pin DIN C male connector The manufacturer part number that National Instruments uses for this connector is as follows e ERNI part number 913523 The mating connector for the SCXI 1122 front connector is a 48 pin DIN C female connector National Instruments uses a polarized connector to prevent inadvertent upside down connection to the SCXI 1122 The manufacturer part number that National Instruments uses for this connector is as follows e ERNI part number 913524 right angle pins Unpacking Your SCXI 1122 module is shipped in an antistatic package to prevent electrostatic damage to the module Electrostati
13. warranty includes parts and labor 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 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 Nati
14. 1500 N Mopac Expwy 512 433 8641 Austin TX 78759 3504 Glossary me Meaning f Ve Numbers Symbols degrees strain gt greater than gt greater than or egual to lt less than negative of or minus Q ohms percent plus or minus positive of or plus 5 V signal 5 VDC Isolated Source signal A A amperes AC alternating current A D analog to digital ADIO Port A Digital Input Output signal 0 lt lt 5 ANSI American National Standards Institute AOGND Analog Output Ground signal Arms amperes root mean square AWG American Wire Gauge B BDIO Port B Digital Input Output signal C C Celsius Ce AC coupling capacitor National Instruments Corporation Glossary 1 SCXI 1122 User Manual Glossary CH CH CJC CJR CJS CMRR CMV D D A DAQD A dB DC DIGGND DIN DOUT E EEPROM FSR GF GMIO Gtotal Ipias IEX IEX TEX 1n SCXI 1122 User Manual Positive Input Channel Number signal Negative Input Channel Number signal cold junction compensation cold junction reference cold junction sensor common mode rejection ratio common mode voltage digital to analog Data Acquisition Board Data Address Line signal decibels direct current Digital Ground signal Deutsche Industrie Norme Data Out Number signal electrically erased programmable read only memory Farads full scale range gauge factor MIO gain SCXI gain total gain hertz bias current current excita
15. 3 8 excitation channel signal connections 3 8 to 3 9 floating AC coupled signal connection referenced to chassis SCXI 1122 User Manual Index ground for better SNR illustration 3 6 floating signal connection referenced to chassis ground for better SNR illustration 3 6 ground referenced signal connection with high common mode voltage illustration 3 6 pin assignments illustration 3 3 signal connection descriptions 3 4 to 3 5 temperature sensor connection 3 9 rear signal connector analog output signal connections 3 11 to 3 12 digital I O signal connections 3 12 to 3 13 pin assignments illustration 3 10 SCXIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 signal descriptions 3 11 safety warnings 3 1 to 3 2 SLOTOSEL signal 3 11 3 12 software programming choices LabVIEW applications software 1 2 LabWindows applications software 1 2 NI DAO driver software 1 2 to 1 3 register level programming 1 4 specifications analog input A 1 to A 3 environment A 3 excitation A 3 physical A 3 Status Register 2 3 4 3 T TEMP signal 3 4 3 5 TEMP signal 3 4 3 5 temperature sensor connection 3 9 4 4 theory of operation analog circuitry 4 3 to 4 7 analog input channels 4 3 excitation output channels 4 3 to 4 7 digital control circuitry 4 3 functional overview 4 1 to 4 2 major components of SCXI 1122 4 3 rear signal connector 4 3 SCXI 1122 block diagram 4 2
16. AA EWE 5 1 DO b 5 1 C ahlibraliom PROC EQUUS soe eate eee e ide p ta A AA iud cu dua dees 5 1 Calibration Equipment Requirements eese nee 5 1 Gain and Offset CalibralObusce ce pei passt WA detta dum e cal EUM aS 5 2 Excitation CaliDEAUO1 25 oie etae imet been aclfeenite eo take ees als 5 4 Appendix A AAA A a anata ras ce ode fe CE A 1 Analog NA A 1 TEAL ON ae ac ah Bich Mah ln toti io cat ae A era ca ida ait A 3 Phiysical A AAA AA AAA WAA A 3 BU VICO DE s uscire htec A iae buses de topi tectae t Saeed A 3 Appendix B Customer COMMUNICA ION ooooccicicicicicicnonononnnnonnnonnnonno nooo nono nono no nooo nn nono anar ano an anar an aran anos B 1 AO A A WA TUU Sg AE Glossary 1 iiri io dE Index 1 SCXI 1122 User Manual vi O National Instruments Corporation Figure 1 1 Figure 2 1 Figure 3 1 Figure 3 2 Figure 3 3 Figure 3 4 Figure 3 5 Figure 3 6 Figure 3 7 Figure 3 8 Figure 4 1 Figure 4 2 Figure 4 3 Table 2 1 Table 2 2 Table 2 3 Table 3 1 Table 3 2 Table 4 1 Table 4 2 Table 5 1 O National Instruments Corporation vii Contents Figures The Relationship between the Programming Environment NI DAQ and Xour Hat Ware e SCXI 1122 Parts Locator DIagram aane eee e eee BAG tas SCXI 1122 Front Connector Pin Assignment eee Ground Referenced Signal Connection with High Common Mode Voltage Floating Signal Connection Referenced to
17. Analog Input Channel Signal Connections The positive input channel signal terminals are located in column B of the connector Their corresponding negative input channel signal terminals are located in column C of the connector Each input corresponds to a separate relay that are all multiplexed into the amplifier input selector In addition to the relay inputs the temperature sensor output from the terminal block located on pins A3 TEMP and Al TEMP is also connected to the amplifier input selector All inputs are fully isolated from earth ground and are in a floating single ended configuration hence you can measure signals that have a common mode voltage up to 480 Vrms Notice that the maximum allowable channel to channel common mode voltage is 250 Vrms Warning EXCEEDING THE INPUT SIGNAL RANGE RESULTS IN DISTORTED SIGNALS Exceeding the maximum input voltage rating 250 Vrms between positive and negative inputs or outputs 250 Vrms between input or output channels and 480 Vrms between input or output channels and earth ground can damage the SCXI 1122 the SCXIbus and the DAQ board National Instruments is NOT liable for any damages or injuries resulting from such signal connections For better noise immunity and if all the measured signals are floating connect the negative input channels to chassis ground on the terminal block using the solder lug attached to the strain relief bar Figure 3 2 shows how to connect a ground referenced sig
18. BILITY 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 EKPECTED 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 COMPUTER 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
19. Chassis Ground for Better SNR Floating AC Coupled Signal Connection Referenced to Chassis Ground for Better SNR cuina des tage i id AC Coupled Signal Connection with High Common Mode Voltage Avoiding Relay Wear by Sampling and Averaging Rather Than Single Sample Channel Scanning eiie eter eoi Hoe SEP manana Connecting a Quarter Bridge Strain Gauge to Channel O SCXI 1122 Rear Signal Connector Pin Assignments eee SCXI LI22 BIOCE IDL Ag rat ir Series Connection with Current Excitation oooonoocccnnocccnoncnononcnononcnnnnnccnnnncnnannno Four Wire Scan Connection with Multiplexed Current Excitation Tables Digital Signal Connection Jumper Settings see E aN User Defined Current Receiver Resistors tai iii da Maximum Load per Excitation Channel eee SCXIbus to SCXI 1122 Rear Signal Connector to DAQ Board Pin EGquivalenbes a A Sense Current Output Channel Associations esee Pros and Cons of Two Wire and Four Wire Connections with Current Excited Transducers eese eene hene eee ee nnn Maximum Allowable Error Ranges eere ee eee eee eene eene eene etant SCXI 1122 User Manual About This Manual This manual describes the electrical and mechanical aspects of the SCXI 1122 and contains information concerning its operation The SCXI 1122 is a member of t
20. F 5 AT MIO 16X AT MIO 16D AT MIO 64F 5 NB MIO 16 and NB MIO 16X unless otherwise noted monospace Lowercase text in this font denotes text or characters that are to be literally input 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 variables filenames and extensions and for statements and comments taken from program code NB NB refers to the NuBus series computers PC PC refers to the IBM PC XT the IBM PC AT and compatible computers SCXTIbus SCXIbus refers to the backplane in the chassis A signal on the backplane 1s referred to as the SCXIbus lt signal name gt line or signal The SCXIbus descriptor may be omitted when the meaning is clear Descriptions of all SCXIbus signals are in Chapter 3 Signal Connections Slot 0 Slot 0 refers to the power supply and control circuitry in the SCXI chassis Abbreviations acronyms metric prefixes mnemonics symbols and terms are listed in the Glossary SCXI 1122 User Manual x National Instruments Corporation About This Manual The National Instruments Documentation Set The SCXI 1122 User Manual is one piece of the documentation set for your SCXI system You should have six types of manuals Use these different types of manuals as follows e Getting Started with SCXI This is the first manual you should rea
21. Jojojes indu jeyiduiy eoinog eDeyoA 39105 jueuno due onuoo Jejunot Jejuno X3l Joyenuenv junus X3l s XJA uonoeloJd 1ndinoy Linduj 8 sAejay indu g Figure 4 1 SCXI 1122 Block Diagram O National Instruments Corporation 4 2 SCXI 1122 User Manual Chapter 4 Theory of Operation The major components of the SCXI 1122 are as follows e The rear signal connector e The SCXIbus connector The SCXIbus interface The digital control circuitry e The analog circuitry The SCXI 1122 consists of 16 isolated multiplexed channels with gains of 0 01 0 02 0 05 0 1 0 2 0 5 1 2 5 10 20 50 100 200 500 1 000 and 2 000 and two isolated excitation channels with voltage and current excitation The SCXI 1122 also has a digital section for automatic control of channel scanning temperature selection gain selection and filter selection The remainder of this chapter describes the theory of operation for each of these components Rear Signal Connector SCXIbus Connector and SCXIbus Interface The SCXIbus controls the SCXI 1122 The SCXIbus interface interfaces the signals of the rear signal connector to the SCXIbus allowing a DAQ board to control the SCXI 1122 and the rest of the chassis Digital Control Circuitry The digital control section consists of the Address Handler Register the Configuration Register the Status Register and the Module ID Register The Address Ha
22. SCXI 1122 User Manual Sixteen Channel Isolated Transducer Multiplexer Module for Signal Conditioning September 1999 Edition Part Number 320516B 01 O Copyright 1993 1999 National Instruments Corporation All Rights Reserved Worldwide Technical Support and Product Information www natinst com National Instruments Corporate Headguarters 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 Ontario 905 785 0085 Canada Qu bec 514 694 8521 China 0755 3904939 Denmark 45 76 26 00 Finland 09 725 725 11 France 01 48 14 24 24 Greece 30 1 42 96 427 Germany 089 741 31 30 Hong Kong 2645 3186 India 91805275406 Israel 03 6120092 Italy 02 413091 Japan 03 5472 2970 Korea 02 596 7456 Mexico D F 5 280 7625 Mexico Monterrey 8 357 7695 Netherlands 0348 433466 Norway 32 27 73 00 Singapore 2265886 Spain Barcelona 93 582 0251 Spain Madrid 91 640 0085 Sweden 08 587 895 00 Switzerland 056 200 51 51 Taiwan 02 377 1200 United Kingdom 01635 523545 Warranty The SCXI 1122 is 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
23. SCXIbus connector 4 3 SCXIbus interface 4 3 SCXI 1122 User Manual Index 4 U unpacking the SCXI 1122 1 5 user defined current receiver resistors See current loop receivers V VEX signal 3 4 4 5 VEX 2 signal 3 4 VEX signal 3 4 4 5 voltage VEX excitation channel 3 8 W Wheatstone bridge 4 5 O National Instruments Corporation
24. al Instruments manual contains detailed information for the register level programmer e SCXI 1122 Register Level Programmer Manual part number 340696 01 This manual is available from National Instruments by request If you are using NI DAQ LabVIEW or LabWindows you should not need the register level programmer manual Using NI DAQ LabVIEW or LabWindows is quicker and easier than and as flexible as using the low level programming described in the register level programmer manual Refer to Software Programming Choices in Chapter 1 Introduction of this manual to learn about your programming options O National Instruments Corporation xi SCXI 1122 User Manual About This Manual Customer Communication National Instruments wants to receive your comments on our products and manuals We are interested in the applications you develop with our products and we want to help if you have problems with them To make it easy for you to contact us this manual contains comment and configuration forms for you to complete These forms are in Appendix B Customer Communication at the end of this manual SCXI 1122 User Manual xii O National Instruments Corporation Chapter 1 Introduction This chapter describes the SCXI 1122 lists the contents of your SCXI 1122 kit describes the optional software optional equipment and custom cables and explains how to unpack the SCXI 1122 The SCXI 1122 has 16 isolated input channels and two isolated exci
25. al adapter or the SCXI 1351 one slot cable extender with the SCXI 1122 read this section Figure 3 8 shows the SCXI 1122 rear signal connector pin assignments OUTREF DIGGND SERDATIN SERDATOUT DAQD A SLOTOSEL DIGGND SCANCLK SERCLK Figure 3 8 SCXI 1122 Rear Signal Connector Pin Assignments SCXI 1122 User Manual 3 10 O National Instruments Corporation Chapter 3 Signal Connections Rear Signal Connection Descriptions Pin 1 2 3 4 19 24 33 25 26 27 29 36 37 43 46 All other pins are not connected Signal Name AOGND MCHO0 OUTREF DIGGND SERDATIN SERDATOUT DAQD A SLOTOSEL SCANCLK SERCLK RSVD Description Analog Output Ground These pins are connected to the analog reference when jumper W1 is in position AB RO Analog Output Channels 0 Connects to the DAQ board differential analog input channels Output Reference This pin serves as the reference node for the analog channels output in the pseudodifferential reference mode It should be connected to the analog input sense of the NRSE DAQ board Digital Ground These pins supply the reference for DAQ board digital signals and are tied to the module digital ground Serial Data In This signal taps into the SCXIbus MOSI line to send serial input data to a module or Slot 0 Serial Data Out This signal taps into the SCXIbus MISO line to accept serial output data from a module DAQ Board Data
26. at there are no signals connected to your module front connector A SHOCK HAZARD T his unit should only be opened by qualified personnel aware of the dangers involved Disconnect all power before removing the cover Always install the grounding screw If signal wires are connected to the module or terminal block dangerous voltages may exist even when the equipment is turned off Before you remove any installed module disconnect the AC power line or any high voltage sources 2 30 Vrms 42 4 Vpk or 60 Vdc that may be connected to the module To install the resistors you need to do the following before installing your module in the SCXI chassis 1 2 3 4 5 6 7 8 9 Ground yourself via a grounding strap or via a ground connected to your SCXI chassis Properly grounding yourself prevents damage to your SCXI module from electrostatic discharge Remove the module cover by unscrewing the grounding screw at the rear of the module Remove the rear panel by unscrewing the two remaining screws Slide the module out of its enclosure Insert the resistor s into the appropriate pad Solder the leads to the pads on the solder side of the module Trim the leads to 0 06 in maximum Slide the module back into its enclosure Reinstall the rear panel 10 Reinstall the top cover and grounding screw 11 Your module is ready to be installed into the chassis O National Instruments Corporation 2 5 SCXI 1122 User Manual Configu
27. ber SCXI 1122 module 182366 01 SCXI 1122 User Manual 320516 01 If your kit is missing any of the components contact National Instruments Detailed specifications of the SCXI 1122 are listed in Appendix A Specifications O National Instruments Corporation 1 1 SCXI 1122 User Manual Introduction Chapter 1 Software Programming Choices There are four options to choose from when programming your National Instruments plug in DAQ board and SCXI hardware You can use LabVIEW LabWindows NI DAQ or register level programming software LabVIEW and LabWindows Application Software LabVIEW and LabWindows are innovative program development software packages for data acquisition and control applications LabVIEW uses graphical programming whereas LabWindows enhances traditional programming languages Both packages include extensive libraries for data acquisition instrument control data analysis and graphical data presentation LabVIEW currently runs on three different platforms AT MC EISA computers running Microsoft Windows the Macintosh platform and the Sun SPARCstation platform 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 VIs for using LabVIEW with National Instruments boards is included with LabVIEW The LabVIEW Data Acquisition VI Libraries are functionally equivalent to the NI DAQ software LabWindows
28. blem include the configuration forms from their user manuals Include additional pages if necessary Name Company Address Fax Phone ___ Computer brand Model Processor Operating system Speed MHz RAM MB Display adapter Mouse yes no Other adapters installed Hard disk capacity MB Brand Instruments used National Instruments hardware product model Revision Configuration National Instruments software product Version Configuration The problem is List any error messages The following steps will reproduce the problem SCXI 1122 Hardware Configuration Form Record the settings and revisions of your hardware and software on the line to the right of each item Complete a new copy of this form each time you revise your software or hardware configuration and use this form as a reference for your current configuration Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently e SCXI 1122 Revision Letter e Chassis Slot e Grounding Shielding and Reference Mode Selection Factory Setting Parking position W1 A ROR1 e SERDATOUT Resistor Pull up Jumper Factory Setting Enabled W2 position 1 e Other Modules in System DAQ Boards Installed Register Level Programmer Manual Request Form National Instruments encourages you to comment on the documentation supplied with our produc
29. c discharge can damage several components on the module To avoid such damage in handling the module take the following precautions e Ground yourself via a grounding strap or by holding a grounded chassis such as your SCXI chassis Touch the antistatic package to a metal part of your SCXI chassis before removing the module from the package Remove the module from the package and inspect the module for loose components or any other sign of damage Notify National Instruments if the module appears damaged in any way Do not install a damaged module into your SCXI chassis e Never touch the exposed pins of connectors O National Instruments Corporation 1 5 SCXI 1122 User Manual Chapter 2 Configuration and Installation This chapter describes how to configure the SCXI 1122 jumpers and how to install the SCXI 1122 into the SCXI chassis Module Configuration The SCXI 1122 contains two jumpers that are shown in the parts locator diagram in Figure 2 1 Jumper W2 connects a pullup resistor to the SERDATOUT signal on the rear signal connector Jumper W1 configures the guard and the analog output ground and enables the pseudodifferential reference mode You must use software to further configure the module Refer to your software manuals or to the SCXI 1122 Register Level Programmer Manual if you are a register level programmer O National Instruments Corporation 2 1 SCXI 1122 User Manual Chapter 2 Configuration and Installation
30. common mode voltage volts direct current Voltage Excitation Channel signal Negative Voltage Excitation Output signal Positive Voltage Excitation Output signal Half Voltage Excitation Output signal Virtual Instrument input logic high voltage input logic low voltage offset bias voltage output logic high voltage output logic low voltage volts root mean square watts Glossary 4 O National Instruments Corporation Index Numbers 5 V signal 3 4 A AC coupled signal connection with high common mode voltage illustration 3 7 Address Handler Register 4 3 analog circuitry 4 3 to 4 7 analog input channels 4 3 excitation output channels 4 3 to 4 7 analog configuration 2 3 to 2 5 current loop receivers 2 4 to 2 5 jumper settings table 2 4 analog input channel signal connections 3 5 to 3 8 AC coupled signal connection with high common mode voltage illustration 3 7 connecting external resistors 3 7 floating AC coupled signal connection referenced to chassis ground illustration 3 6 floating signal connection referenced to chassis ground illustration 3 6 ground referenced signal connection with high common mode voltage illustration 3 6 analog input channels sense current output channel associations illustration 4 4 specifications A 1 to A 3 theory of operation 4 3 to 4 4 analog output signal connections 3 11 to 3 12 AOGND signal 3 11 C cables custom cables 1 5 optional equipment
31. d It gives an overview of the SCXI system and contains the most commonly needed information for the modules chassis and software e Your SCXI module user manuals These manuals contain detailed information about signals connections and module configuration They also explain in greater detail how the module works and application hints Your DAQ board user manuals These manuals have detailed information about the DAQ board that plugs into your computer Use these manuals for board installation and configuration instructions specification information about your DAQ board and application hints e Software manuals Examples of software manuals you might have are the LabVIEW and LabWindows manual sets and the NI DAQ manuals After you have set up your hardware system use either the application software LabVIEW or LabWindows manuals or the NI DAQ manuals to help you write your application If you have a large and complicated system it is worthwhile to look through the software manuals before you configure your hardware e Accessory manuals These are the terminal block and cable assembly installation guides They explain how to physically connect the relevant pieces of the system together Consult these when you are making your connections e SCXI chassis manuals These manuals contain maintenance information on the chassis installation instructions and information for making custom modules Related Documentation The following Nation
32. e connected to its ground reference Auto zeroing is a method for nulling error sources that compromise the quality of measurements Auto zeroing determines the amount of offset at the output of the SCXI 1122 at a given gain of the amplifier It is recommended to perform auto zeroing at the start of an experiment for each gain to be used to eliminate error due to drift in the amplifier internal circuitry and increase the accuracy of the measurement Notice that the auto zero path is different from the analog input path therefore even after auto zeroing a residual input offset still exists and has a value of less than 6 UV Refer to Appendix A Specifications for further details You can store this offset in the onboard EEPROM for future use and for automatic calibration when you are using National Instruments software The EEPROM also stores correction factors for each gain of the SCXI 1122 as well as for the excitation channels If you are not using National Instruments software refer to the SCXI 1122 Register Level Programmer Manual if you need a more a detailed description of the EEPROM When using National Instruments software such as NI DAQ LabVIEW and LabWindows and you are using the factory determined calibration constants you do not need to read the following section continue reading the Excitation Calibration section You need to read the following section only if you are using National Instruments software and you intend to determine
33. eference to the analog output ground AOGND pins 1 and 2 on the rear signal connector Select this configuration if you are using an RSE DAQ board Do not use a differential input DAQ board when jumper W1 is in this position Connects SCXIbus guard to the analog reference Enables the pseudodifferential reference mode and connects the analog reference to the OUTREF pin on the rear signal connector Select this mode when the SCXI 1122 has to operate with DAQ boards that have a nonreferenced single ended NRSE input Do not use differential input DAQ boards when jumper W1 is in this position Current Loop Receivers The SCXI 1122 has pads for transforming individual channels to current to voltage converters National Instruments offers an SCXI process current pack which consists of a package of four 249 QO 0 1 5 ppm 1 4 W resistors You can find the part number for this kit in the Optional Equipment section of Chapter 1 Introduction Table 2 3 shows the input channel and its corresponding resistor reference designator Table 2 3 User Defined Current Receiver Resistors Input Channel Resistor Reference Designator 1 2 3 SCXI 1122 User Manual 2 4 O National Instruments Corporation continues Chapter 2 Configuration and Installation Table 2 3 User Defined Current Receiver Resistors Continued Input Channel Resistor Reference Designator Warning Before installing the resistors in your module make sure th
34. equent measurements Gain and Offset Calibration To determine the offset and gain calibration factors of the SCXI 1122 at a given gain Gs perform the following steps for a two point calibration 1 Set the SCXI 1122 to the desired gain 2 Depending on how you want to calibrate your module you can perform one of the following procedures Auto zeroing selects one of the calibration points to be at 0 V input and you must provide the other calibration point at positive or negative full scale a Enable auto zeroing b Measure the SCXI 1122 output with the DMM and store the measured value for future use c Disable auto zeroing d Apply 9 9 V G or 9 9 V G to the amplifier input e Go to step 3 SCXI 1122 User Manual 5 2 O National Instruments Corporation Chapter 5 Calibration e To select positive and negative full scale to be the two calibration points apply 9 9 V Gs and 9 9 V G a Apply 9 9 V G to the amplifier input b Measure the input voltage with the DMM and store the measured value c Measure the SCXI 1122 output with the DMM and store the measured value d Apply 9 9 V G at the amplifier input e Go to step 3 Note If you are using a calibrator that supplies accurate voltages you can skip step c directly above and step 3 below 3 Measure the input voltage with the DMM and the store the measured value 4 Measure the SCXI 1122 output with the DMM and store the measured value 5 You n
35. erance resistors with a temperature coefficient of 2 ppm C These resistors are connected in series To use the network connect the VEX 2 screw terminal on the terminal block to the negative input of the channel of interest 120 9 Dummy Resistor SCXI 1322 Terminal Block Figure 3 7 Connecting a Quarter Bridge Strain Gauge to Channel 0 Note When using the half bridge completion network with a quarter bridge setup you must use an extra resistor to complete the bridge Place this resistor on the terminal block between the positive input channel and the negative excitation output Temperature Sensor Connection Pins Al and A3 are for connecting the isolated temperature sensor located on the SCXI 1322 terminal block for cold junction compensation CJC of thermocouples connected to the SCXI 1122 The connection is overvoltage protected to 250 Vrms with power on and off Warning Exceeding the overvoltage protection on the temperature connections can damage the SCXI 1122 the SCXIbus and the DAQ board National Instruments is NOT liable for any damages resulting from such signal connections O National Instruments Corporation 3 9 SCXI 1122 User Manual Signal Connections Chapter 3 Rear Signal Connector Note If you are using the SCXI 1122 with a National Instruments DAQ board and cable assembly you do not need to read the remainder of this chapter If you are using the SCXI 1180 feedthrough panel the SCX1 1343 rear screw termin
36. es for MPW C THINK C Pascal and Microsoft QuickBASIC Any language that uses Device Manager Toolbox calls can access NI DAQ software for Macintosh You can use NB Series DAQ boards and SCXI hardware with NI DAQ software for Macintosh O National Instruments Corporation 1 3 SCXI 1122 User Manual Introduction Chapter 1 Register Level Programming The final option for programming any National Instruments DAO hardware is to write register level software Writing register level programming software can be very time consuming and inefficient and is not recommended for most users The only users who should consider writing register level software should meet at least one of the following criteria e National Instruments does not support your operating system or programming language You are an experienced register level programmer who is more comfortable writing your own register level software Always consider using NI DAQ LabVIEW or LabWindows to program your National Instruments DAQ hardware Using the NI DAQ LabVIEW or LabWindows software is easier than and as flexible as register level programming and can save you weeks of development time The SCXI 1122 User Manual and your software manuals contain complete instructions for programming your DAQ board with NI DAQ LabVIEW or LabWindows If you are using NI DAQ LabVIEW or LabWindows to control your board you should not need the register level programmer manual The SCXI 1122 Re
37. g warnings contain important safety information concerning hazardous voltages Warnings You MUST insulate all of your signal connections appropriately to the HIGHEST available voltage with which the SCXI 1122 may come in contact ANY voltage connected to the SCXI 1122 connector may appear on any other pin of this connector Treat all signals on the SCXI 1122 front connector as hazardous if any signals on the front connector are greater than or equal to 30 Vrms 42 4 Vpk or 60 Vdc DO NOT OPERATE THE MODULE IN AN EXPLOSIVE ATMOSPHERE OR WHERE THERE MAY BE FLAMMABLE GASES OR FUMES SHOCK HAZARD This unit should only be opened by qualified personnel aware of the dangers involved Disconnect all power before removing the cover Always install the grounding screw If signal wires are connected to the module or terminal block dangerous voltages may exist even when the equipment is turned off Before you remove any installed terminal block or module disconnect the AC power line or any high voltage sources 2 30 Vrms 42 4 Vpk or 60 VDC that may be connected to the terminal block or module DO NOT OPERATE DAMAGED EQUIPMENT The safety protection features built into this module can be impaired if the module becomes damaged in any way If it is damaged turn the module off and do not use it until service trained personnel can check its safety If necessary return the module to National Instruments for service and repair to ensure that its safety is
38. gister Level Programmer Manual contains low level programming details such as register maps bit descriptions and register programming hints that you will need only for register level programming Some hardware user manuals include register map descriptions and register programming hints If your manual does not contain a register map description and you want to obtain the register level programmer manual please fill out the Register Level Programmer Manual Request Form at the end of this manual and send it to National Instruments Optional Equipment Equipment Part Number SCXI 1322 front terminal block 776573 22 SCXI 1340 cable assembly 776574 40 SCXI 1341 Lab NB Lab PC Lab PC cable assembly 776574 41 SCXI 1342 PC LPM 16 cable assembly 776574 42 SCXI 1343 rear screw terminal adapter 776574 43 SCXI 1344 Lab LC cable assembly 776574 44 SCXI 1345 shielded cable with adapter 1 m 776574 451 776574 452 776574 455 776574 450 SCXI 1350 multichassis adapter 776575 50 SCXI process current resistor kit 776582 01 Standard ribbon cable 0 5 m 180524 05 1 0m 180524 10 1 Resistor kit needed to perform current measurements See pages 2 4 Refer to Chapter 3 Signal Connections and to your cable installation guide for additional information on cabling connectors and adapters SCXI 1122 User Manual 1 4 National Instruments Corporation Chapter 1 Introduction Custom Cables The SCXI 1122 rear signal connector is a 50 pin male ribbon
39. hange 0 3321 mV Replacing the strained voltage with V change in the quarter bridge strain equation produces an equivalent 199 WE of change Also the module has an internal completion network that you can use with half bridge or quarter bridge networks To use this completion network simply connect the VEX 2 terminal to the negative input channel of the appropriate transducer channel In case of a quarter bridge configuration you must provide an additional resistor equal in value to your nominal strain National Instruments Corporation 4 5 SCXI 1122 User Manual Theory of Operation Chapter 4 gauge resistor to complete the bridge network Connect this resistor in your SCXI 1322 terminal block between the CH and VEX terminals The current output channel is provided for transducers such as thermistors and RTDs which need a current excitation to operate properly The current output has a value of 1 mA and has a maximum permissible load of 5 KO If you connect loads greater than 5 kQ the current source will lose regulation When connecting several loads which need current excitation you have two possible approaches The first is to connect them all in series as long as they do not exceed 5 kQ total and use the two wire scan mode as shown in Figure 4 2 or use the four wire scan mode and have them connected as shown in Figure 4 3 RT R1 4R15 lt 5 ka Figure 4 2 Series Connection with Current Excitation CH 8 CH 0 CH
40. has two versions LabWindows for DOS is for use on PCs running DOS and LabWindows CVI is for use on PCs running Windows and Sun SPARCstations LabWindows CVI features interactive graphics a state of the art user interface and uses the ANSI standard C programming language The LabWindows Data Acquisition Library a series of functions for using LabWindows with National Instruments boards is included with LabWindows for DOS and LabWindows CVI The LabWindows Data Acquisition libraries are functionally equivalent to the NI DAQ software Using LabVIEW or LabWindows software will greatly diminish the development time for your data acquisition and control application Part numbers for these software products are as follows LabVIEW for Windows 776670 01 Lab VIEW for Macintosh 776141 01 LabWindows for DOS 776475 01 LabWindows CVI for Windows 776800 01 NI DAO Driver Software The NI DAO driver software is included at no charge with all National Instruments DAO boards NI DAO has an extensive library of functions that you can call from your application programming environment These functions include routines for analog input A D conversion buffered data acquisition high speed A D conversion analog output D A conversion waveform generation digital I O counter timer operations SCXI RTSI self calibration messaging and acquiring data to extended memory SCXI 1122 User Manual 1 2 O National Instruments Corporation Chapter 1 Introduct
41. he National Instruments Signal Conditioning eXtensions for Instrumentation SCXT Series for the National Instruments DAQ plug in boards This module is designed for signal conditioning of strain gauges RTDs thermistors thermocouples volt and millivolt sources and 4 to 20 mA sources or 0 to 20 mA process current sources where high common mode voltages exist The SCXI 1122 operates as 16 isolated input channels one isolated current excitation channel and one voltage excitation channel All 16 channels are isolated from earth ground but not from each other The excitation circuits are both isolated from earth ground the input channels and between each other Organization of This Manual The SCXI 1122 User Manual is organized as follows e Chapter 1 Introduction describes the SCXI 1122 lists the contents of your SCXI 1122 kit describes the optional software optional equipment and custom cables and explains how to unpack the SCXI 1122 e Chapter 2 Configuration and Installation describes how to configure the SCXI 1122 jumpers and how to install the SCXI 1122 into the SCXI chassis e Chapter 3 Signal Connections describes the input and output signal connections to the SCXI 1122 module via the SCXI 1122 front connector and rear signal connector This chapter also includes specifications and connection instructions for the signals on the SCXI 1122 connectors Chapter 4 Theory of Operation contains a functional overview of the SCXI
42. he load for remote sensing When using the SCXI 1322 terminal block this pin is connected to VEX SENSE screw terminals This pin is not protected Positive Voltage Excitation Output This pin is connected to the voltage excitation positive output Negative Current Excitation Output This pin is connected to the current excitation negative output Positive Current Excitation Output This pin is connected to the current excitation positive output No Connect Do not connect any signal to these pins Reserved This pin is reserved Do not connect any signal to this pin Positive Input Channel These pins are connected to the positive input channels 0 through 15 respectively Negative Input Channel These pins are connected to the negative input channels 0 through 15 respectively 3 4 O National Instruments Corporation Chapter 3 Signal Connections The signals on the front connector are all analog except pins A7 and A31 which are digital The analog signals are grouped into analog input channels excitation channels and temperature sensor signals Signal connection guidelines for each of these groups are described in the following sections Notes All pins are overvoltage protected to 250 Vrms except for pin A7 5 V signal pin 31 RSVD pin A17 SENSE and pin A11 VEX 2 All inputs and outputs on the front connector are isolated The maximum working common mode voltage to earth is 480 Vrms and between channels is 250 Vrms
43. ion NI DAQ also internally addresses many of the complex issues between the computer and the plug in board such as programming interrupts and DMA controllers NI DAQ maintains a consistent software interface among its different versions so that you can change platforms with minimal modifications to your code Figure 1 1 illustrates the relationship between NI DAQ and LabVIEW and LabWindows You can see that the data acquisition parts of LabVIEW and LabWindows are functionally equivalent to the NI DAQ software Conventional Programming LabVIEW LabWindows Environment PC or Macintosh PC PC or Macintosh NI DAQ Driver Software Data Acquisition Personal Boards or Computer or SCXI Hardware Workstation Figure 1 1 The Relationship between the Programming Environment NI DAQ and Your Hardware The National Instruments PC AT and MC Series DAQ boards are packaged with NI DAQ software for PC compatibles NI DAQ software for PC compatibles comes with language interfaces for Professional BASIC Turbo Pascal Turbo C Turbo C Borland C and Microsoft C for DOS and Visual Basic Turbo Pascal Microsoft C with SDK and Borland C for Windows You can use your SCXI 1122 together with other PC AT and MC Series DAQ boards and SCXI hardware with NI DAQ software for PC compatibles The National Instruments NB Series DAQ boards are packaged with NI DAQ software for Macintosh NI DAQ software for Macintosh comes with language interfac
44. ion by the DAQ board during scanning This signal is referred to as SCANCLK e Pin 43 is a reserved digital input e Pin 46 is a reserved digital input The following specifications and ratings apply to the digital I O lines e Absolute maximum voltage input rating 5 5 V with respect to DIGGND Digital input specifications referenced to DIGGND Vg input logic high voltage 2 V minimum Vy input logic low voltage 0 8 V maximum I input current leakage 1 UA maximum Digital output specifications referenced to DIGGND Von output logic high voltage 3 7 V minimum at 4 mA maximum Vg output logic low voltage 0 4 V maximum at 4 mA maximum O National Instruments Corporation 3 13 SCXI 1122 User Manual Chapter 4 Theory of Operation This chapter contains a functional overview of the SCXI 1122 module and explains the operation of each functional unit making up the SCXI 1122 Functional Overview The block diagram in Figure 4 1 illustrates the key functional components of the SCXI 1122 O National Instruments Corporation 4 1 SCXI 1122 User Manual Chapter 4 Theory of Operation 10199UU09 SNQIXOS e J0 99UU09 eufirs Jesy lt 0gv yms 0gv Jo3uo9 jndino Y 9S Jd 1 ules NOyd33 uoge eoeyelu 4193151634 SNIS 3 103000 2181 Ja siBay uoneunbijuo9 Joyenus renuenv v 03002 NANO 033002 onuoo 10429199 pue Jaes 4d1 08V indujjeynduv 19S 4d1 X3llN JOUOD uonoejes Indu 1eyiduuv
45. le installation guide 6 Check the installation 7 Turn on the SCXI chassis 8 Turn on the computer or reconnect it to your chassis The SCXI 1122 module is installed You are now ready to install and configure your software If you are using NI DAQ refer to the NI DAO User Manual for PC Compatibles The software installation and configuration instructions are in Chapter 1 Introduction to NI DAQ Find the installation and system configuration section for your operating system and follow the instructions given there If you are using LabVIEW the software installation instructions are in your LabVIEW release notes After you have installed LabVIEW refer to the Configuring LabVIEW section of Chapter 1 of your LabVIEW user manual for software configuration instructions If you are using LabWindows the software installation instructions are in Part 1 Introduction to LabWindows of the Getting Started with LabWindows manual After you have installed LabWindows refer to Chapter 1 Configuring LabWindows of the LabWindows User Manual for software configuration instructions SCXI 1122 User Manual 2 6 O National Instruments Corporation Chapter 3 Signal Connections This chapter describes the input and output signal connections to the SCXI 1122 module via the SCXI 1122 front connector and rear signal connector This chapter also includes specifications and connection instructions for the signals on the SCXI 1122 connectors The followin
46. le is for reading the Module ID Register the Status Register and the EEPROM National Instruments software does not read the Module ID automatically you must indicate to the software which module is in which slot An open collector driver a driver that actively drives low or goes to high impedance state relying on a pullup resistor to make the signal line go high drives the SERDATOUT line When using a single chassis set jumper W2 in position 1 on the SCXI 1122 that is connected to the DAQ board In this setting the module drives MISO to SERDATOUT and connects the necessary pullup resistor to the SERDATOUT line When using multiple chassis set jumper W2 to position 1 on only one of the SCXI 1122s that are cabled to the DAQ board It does not matter which of the SCXI 1122s that are cabled to the DAQ board has the pullup connected Set jumper W2 in position 3 on all of the other SCXI 1122 modules that are cabled to the DAQ board because if too many pullup resistors are attached to the SERDATOUT line the drivers cannot drive the line low Analog Configuration The SCXI 1122 has one analog configuration jumper jumper W1 for grounding shielding and reference mode selection shown in Table 2 2 O National Instruments Corporation 2 3 SCXI 1122 User Manual Configuration and Installation Chapter 2 Table 2 2 Jumper W1 Settings Grounding Unconnected position factory setting shielding and reference mode selection Connects the analog r
47. n an earth ground wire in the cable from the signal source to the terminal block National Instruments is NOT liable for any damages or injuries resulting from inadequate safety earth ground connections To comply with UL and CE requirements use this module only with a UL listed SCXI chassis Clean devices and terminal blocks by brushing off light dust with a soft nonmetallic brush Remove other contaminants with deionized water and a stiff nonmetallic brush The unit must be completely dry and free from contaminants before returning to service Caution Static electricity is a major cause of component failure To prevent damage to the electrical components in the module observe antistatic techniques whenever removing a module from the mainframe or whenever working on a module SCXI 1122 User Manual 3 2 O National Instruments Corporation Chapter 3 Signal Connections Front Connector Figure 3 1 shows the pin assignments for the SCXI 1122 front connector VAN If a relay fails there exists a potential shock hazard on the inputs that are not in contact with hazardous voltages For this reason treat all inputs as potentially hazardous if any inputs are in contact with hazardous voltages 230 Vrms 42 4 Vpk or 60 Vdc Pin Signal Column Signal Number Name A B C Name CH 0 RSVD CH 1 CH 2 CH 3 CH 4 IEX CH 5 IEX CH 6 VEX CH 7 SENSE CH 8 SENSE CH 9 VEX CH 10 VEX 2 CH 11 CH
48. n to the isolated input channels the SCXI 1122 has isolated excitation channels one 3 333 V voltage output source and one 1 mA current output source Both like the relay input channel have a 480 Vrms common mode voltage with respect to earth ground and 250 Vrms common mode voltage between each other and any other channel Both channels are overvoltage protected to 250 Vrms and are current limited The voltage excitation channel is provided for transducers such as strain gauges which need voltage excitation to operate properly The maximum current sourcing that this channel can provide is 225 mA Exceeding this limit will cause the channel to lose regulation This channel has four terminals two sense terminals SENSE and SENSE and two excitation terminals VEX and VEX This is done to provide remote load regulation For proper operation the SENSE terminal must always be connected to the VEX and the SENSE terminal to the VEX Refer to the SCXI 1322 Terminal Block Installation Guide for further details on using the sense terminals for remote load sensing One of the primary applications of this channel is to provide power to a strain gauge configured in a Wheatstone bridge To permit verification of proper bridge operation we have provided you with shunt calibration means This can be done programmatically When you select shunt calibration while you are performing a Wheatstone bridge strain measurement a 301 kQ 1 resistor internally sh
49. nal Figure 3 3 shows how to connect a floating signal Figures 3 4 and 3 5 show how to connect AC coupled signals O National Instruments Corporation 3 5 SCXI 1122 User Manual Signal Connections Chapter 3 h Figure 3 2 Ground Referenced Signal Connection with High Common Mode Voltage Figure 3 3 Floating Signal Connection Referenced to Chassis Ground for Better SNR Figure 3 4 Floating AC Coupled Signal Connection Referenced to Chassis Ground for Better SNR SCXI 1122 User Manual 3 6 O National Instruments Corporation Chapter 3 Signal Connections Figure 3 5 AC Coupled Signal Connection with High Common Mode Voltage For AC coupled signals connect an external resistor from the positive input channel to the signal reference to provide the DC path for the positive input bias current Typical resistor values range from 100 KO to 1 MQ This solution although necessary in this case lowers the input impedance of the input channel amplifier and introduces an additional offset voltage proportional to the input bias current and to the resistor value used The typical input bias current of the amplifier consists of 80 pA and a negligible offset drift current A 100 k bias resistor results in 8 UV of offset which is insignificant in most applications However if you use larger resistors significant input offset may result To determine the maximum offset the biasing resistor will introduce use the following equation V ofsbia
50. nced signal connection with high common mode voltage illustration 3 6 H half bridge completion network 3 9 4 5 hardware installation See installation I IEX signal 3 4 IEX signal 3 4 installation See also configuration current loop receivers resistors 2 4 to 2 5 hardware installation 2 6 unpacking the SCXI 1122 1 5 internal half bridge completion 3 9 4 5 isolation amplifier 4 4 J jumper settings analog configuration table 2 4 digital signal connections table 2 3 L Lab NB PC PC boards SCXTIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 LabVIEW applications software 1 2 2 6 LabWindows applications software 1 2 2 6 O National Instruments Corporation M manual See documentation MCHO signal 3 11 3 12 MIO 16 boards SCXTIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 MISO line 2 3 module configuration See configuration Module ID Register 2 3 4 3 N NI DAO driver software 1 2 to 1 3 2 6 noise immunity 3 5 O open collector driver 2 3 operation of SCXI 1122 See theory of operation optional equipment 1 4 to 1 5 OUTREF signal 3 11 3 12 P parts locator diagram 2 2 PC LPM 16 board SCXTIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 physical specifications A 3 pin assignments front connector illustration 3 3 rear signal connector ill
51. nced single ended RSE measurements set jumper W1 in position AB RO to connect the SCXI 1122 ground to the DAQ analog ground Pin 19 is the OUTREF pin this pin is connected internally to the analog reference when jumper Wl is in position AB R2 Pins 3 and 4 are the analog output channel of the SCXI 1122 Pins 3 and 4 or MCHO are a multiplexed output of the input channels and the temperature sensor output Notice that the temperature sensor is located on the terminal block Warning The SCXI 1122 analog outputs are not overvoltage protected Applying external voltages to these outputs can damage the SCXI 1122 National Instruments is NOT liable for any damages resulting from such signal connections Note The SCXI 1122 analog outputs are short circuit protected Digital I O Signal Connections Pins 24 through 27 29 33 36 37 43 and 46 constitute the digital I O lines of the rear signal connector the digital input signals the digital output signals and the digital timing signals The digital input signals are pins 24 25 27 29 33 and 37 The DAQ board uses these pins to configure an SCXI module that is under DAQ board control Each digital line emulates the SCXIbus communication signals as follows e Pin 25 SERDATIN is equivalent to the SCXIbus MOSI serial data input line e Pin 27 DAQD A is equivalent to the SCXIbus D A line It indicates to the module whether the incoming serial stream on SERDATIN is data DAQD A 0 or
52. ndler Register controls which register is being addressed The Configuration Register configures the SCXI 1122 such as gain selection shunt calibration filter bandwidth two wire or four wire scanning CJS selection and auto zeroing The Status Register indicates if the SCXI 1122 is done configuring its internal circuitry or is still in progress of doing so The Module ID Register contains the module ID A hex a code unique to the SCXI 1122 You can read this module ID over the SCXIbus to determine the type of module in a particular slot Analog Circuitry The analog circuitry consists of a relay multiplexer a software programmable gain isolation amplifier software programmable filtering a temperature sensor channel for cold junction compensation calibration hardware and voltage and current excitation channel outputs Analog Input Channels The relay multiplexer feeds into the isolation amplifier This relay multiplexer can be configured in two wire or four wire mode scanning In two wire scan mode all sixteen channels operate as voltage sense channels At any point in time one and only one of sixteen channels is connected to the isolation amplifier In the four wire scan mode the sixteen channels are divided into two O National Instruments Corporation 4 5 SCXI 1122 User Manual Theory of Operation Chapter 4 banks which switch synchronously The eight upper channels 0 through 7 operate as voltage sense channels and one out of eight is c
53. new calibration constants Calibration Procedure Calibration Equipment Requirements According to standard practice the equipment used to calibrate the SCXI 1122 should be 10 times as accurate as the SCXI 1122 Practically speaking calibration equipment with four times the accuracy of the item under calibration is generally considered acceptable To calibrate the SCXI 1122 you need the following equipment e For the amplifier gains you need a voltmeter with the following specifications Accuracy 0 002 standard 0 08 sufficient Range 10 to 10 V National Instruments Corporation 5 1 SCXI 1122 User Manual Calibration Chapter 3 Resolution 8 1 digits e For the excitation channels you need a voltmeter with the following specifications Accuracy 0 004 standard 0 16 sufficient Range 0to 45 V Resolution 5 1 digits e You need an ammeter with the following specifications Accuracy 0 004 standard 0 16 sufficient Range mA Resolution 6 digits A multiranging 8 digit digital multimeter can perform all of the necessary functions previously described In the rest of this section the measuring instrument is referred to as a digital multimeter DMM To make sure that the DMM does not introduce an additional offset you can determine the offset errors of the DMM by shorting its leads together and reading the measured value This value the DMM offset must be subtracted from all subs
54. nning Figure 3 6 Avoiding Relay Wear by Sampling and Averaging Rather Than Single Sample Channel Scanning Excitation Channel Signal Connections Your SCXI 1122 has a voltage VEX and a current IEX excitation channel which are available at the front connector In addition VEX 2 is available for half bridge and quarter bridge transducers Both channels are isolated from earth ground up to 480 Vrms working common mode voltage Notice that the voltage and current excitations are electrically isolated from each other but do not provide a safety isolation between them Warning Exceeding the overvoltage protection or isolation rating on the excitation output can damage the SCXI 1122 the SCXIbus and the DAQ board National Instruments is NOT liable for any damages or injuries resulting from such signal connections Excitation Level Each excitation channel of your SCXI 1122 has one level Current excitation mA e Voltage excitation 3 333 V It is important that you do not exceed the maximum permissible load of each channel listed in Table 3 1 SCXI 1122 User Manual 3 8 O National Instruments Corporation Chapter 3 Signal Connections Table 3 1 Mazimum Load per Ezcitation Channel Excitation Level 3 333 V 225 mA 1mA 5 ka Using the Internal Half Bridge Completion Your SCXI 1122 includes half bridge completion for half bridge and guarter bridge setups The completion network consists of two 2 5 KQ 0 02 ratio tol
55. not compromised DO NOT SUBSTITUTE PARTS OR MODIFY EQUIPMENT Because of the danger of introducing additional hazards do not install unauthorized parts or modify the module Return the module to National Instruments for service and repair to ensure that its safety features are 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 hazzard When using the terminal block with high common mode voltages you MUST insulate your signal wires appropriately National Instruments is NOT liable for any damages or injuries resulting from inadequate signal wire insulation O National Instruments Corporation 3 1 SCXI 1122 User Manual Signal Connections Chapter 3 Connections including power signals to ground and vice versa that erceed any of the maximum signal ratings on the SCXI 1122 can damage any or all of the boards connected to the SCXI chassis the host computer and the SCXI 1122 module National Instruments is NOT LIABLE FOR ANY DAMAGES OR INJURIES resulting from incorrect signal connections If high voltages 2 30 Vrms 42 4 Vpk or 60 Vdc are present YOU MUST CONNECT SAFETY EARTH GROUND TO THE STRAIN RELIEF TAB OF THE TERMINAL BLOCK This maintains compliance with UL and CE and protects against electric shock when the terminal block is not connected to the chassis To connect the safety earth ground to the strain relief tab ru
56. oltage if you use the negative full scale voltage and 0 V as your two calibration points When you are making a measurement and using National Instruments software the driver automatically performs the software correction O National Instruments Corporation 5 3 SCXI 1122 User Manual Calibration Chapter 3 Excitation Calibration When using the excitation channels you must retrieve the correction factors for the current and voltage from the EEPROM before using them in your transducer conversion formulas Refer to your software user manual for how to use the SCXI Cal Constants function or VI to perform this task You do not need to read the following section if you are going to use the factory determined correction factors and you are using National Instruments software If you want to determine a new set of voltage excitation calibration constants and you are using National Instruments software use the following procedure 1 Connect a 15 2 resistor to the excitation channel 2 Connect the DMM across the 15 Q load and measure the voltage 3 Pass this voltage to the SCXI Cal Constants function or VI To determine the current excitation calibration constants follow this procedure 1 Set your DMM to DC current measurements 2 Connect the DMM across the IEX and IEX terminals and measure the current 3 Pass this current to the SCXI Cal Constants function or VI Note When calibrating your system you must verif
57. onal Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident 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 LabVIEW NEDAQ natinst com gt National Instruments RTSI and SCXI are trademarks of National Instruments Corporation 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 RELIA
58. onnected to the amplifier at any given pomtin time In addition the eight lower channels 8 through 15 operate as current output channels which switch in tandem with the sense channels At any given point in time one and only one channel is connected to the current output channels Table 4 1 indicates the sense current output channel associations Table 4 1 Sense Current Output Channel Associations Channel 0 Channel 1 Channel 2 Channel 3 Channel 4 Channel 5 Channel 6 Channel 7 Channel 8 Channel 9 Channel 10 Channel 11 Channel 12 Channel 13 Channel 14 Channel 15 The temperature sensor consists of a thermistor located on the SCXI 1322 terminal block This thermistor connects via the temperature channel to the isolation amplifier The temperature sensor is for cold junction compensation of thermocouples When measuring the temperature sensor output set your SCXI 1122 for a gain of five and 4 Hz filter This will increase the measurement resolution and accuracy as well as reduce noise Note With a 4 Hz bandwidth you must wait one second before you take the temperature measurement to permit the system to settle If you want to use the 4 kHz filter take a large number of samples and average them To achieve 50 or 60 Hz rejection you should acquire data over an integral number of power line cycles then average this data The filtering consists of one of two low pass filters 4 kHz 3 dB or 4 Hz 10 dB which you can selec
59. ow have two pairs of voltages Each pair consists of an input voltage and an output voltage For the autozeroing option the pairs are 0 V input offset output and 9 9 V Gs input 9 9 V output or 9 9 V G input 9 9 V output For the positive or negative full scale calibration points option the pairs are 9 9 V Gs input 9 9 V output and 9 9 V G input 9 9 V output 6 Convert the output voltage from volt units to your DAQ board binary unit You must take into consideration the polarity of your DAQ board its resolution 12 bits or 16 bits and gain For example if you are using an AT MIO 16F 5 in bipolar mode and are using a gain of Guo 0 5 your output voltages for the autozeroing option will be represented in binary units as given by the following formula 212 Binary Voltage e i8 GMIO Refer to your DAQ board user manual to determine the appropriate formula for you to use 7 You now have a new set of pairs referred to as voltage binary pairs V inputl Binary outputl and V input2 Binary output2 Pass these pairs to the SCKI Cal Constants function or VI as described in your software user manual Notes When you are using the autozeroing option with 0 V and 9 9 V G this sets your gain error to 0 at 0 V and at positive full scale voltage However because of nonlinearity the error at the negative full scale voltage will be two times the nonlinearity error This is also true for the positive full scale v
60. ration 3 9 exceeding overvoltage protection 3 8 excitation level 3 8 to 3 9 internal half bridge completion 3 9 maximum load per excitation channel table 3 9 excitation output channels calibration 4 4 5 5 four wire scan connection with multiplexed current excitation illustration 4 6 pros and cons of two wire and four wire connections with current excited transducers illustration 4 7 series connection with current excitation illustration 4 6 specifications A 3 theory of operation 4 3 to 4 7 F filtering 4 4 floating AC coupled signal connection referenced to chassis ground for better SNR illustration 3 6 floating signal connection referenced to chassis ground for better SNR illustration 3 6 front connector AC coupled signal connection with high common mode voltage illustration 3 7 analog input channel signal connections 3 5 to 3 8 avoiding relay wear 1llustration 3 8 excitation channel signal connections 3 8 to 3 9 floating AC coupled signal connection referenced to chassis ground for better SNR illustration 3 6 floating signal connection referenced to chassis ground for better SNR illustration 3 6 SCXI 1122 User Manual ground referenced signal connection with high common mode voltage illustration 3 6 pin assignments illustration 3 3 signal connection descriptions 3 4 to 3 5 temperature sensor connection 3 9 G gain and offset calibration 5 2 to 5 3 ground refere
61. ration and Installation Chapter 2 Hardware Installation You can install the SCXI 1122 in any available SCXI chassis slot After you have made any necessary changes and have verified and recorded the jumper settings on the form in Appendix B Customer Communication you are ready to install the SCXI 1122 The following are general installation instructions consult the user manual or technical reference manual of your SCXI chassis for specific instructions and warnings 1 Turn off the computer that contains the DAQ board or disconnect it from your SCXI chassis 2 Turn off the SCXI chassis Do not insert the SCXI 1122 into a chassis that is turned on 3 Insert the SCXI 1122 into the module guides Gently guide the module into the back of the slot until the connectors make good contact If a cable assembly has already been installed in the rear of the chassis the module and cable assembly must be firmly engaged however do not force the module into place 4 Screw the front mounting panel of the SCXI 1122 to the top and bottom threaded strips of your SCXI chassis 5 Ifthis module is to be connected to an MIO 16 DAQ board attach the connector at the metal end of the SCXI 1340 cable assembly to the rear signal connector on the SCXI 1122 module Screw the rear panel to the rear threaded strip Attach the loose end of the cable to the MIO 16 board Note For installation procedures with other SCXI accessories and DAQ boards consult your cab
62. s Ibias X Rbias The input signal range of an SCXI 1122 input channel is 10 V Giota referenced to its negative input where Gi is equal to the gain selected on the SCXI 1122 In addition the input channels are overvoltage protected to 250 Vrms with power on or off at a maximum of 2 5 mArms sink or source Note The SCXI 1122 input multiplexer is composed of relays Relays have a certain life expectancy as listed in Appendix A Specifications To avoid mechanical wear on the relays and when you are acquiring a large number of points per channel and averaging you should acquire the n samples on a given channel before proceeding to the next channel For example rather than performing 100 scans and taking a single sample from each channel during each scan as shown in Figure 3 6a acquire 100 points on each channel then switch to the next channel and acquire a new set of samples as shown in Figure 3 6b O National Instruments Corporation 3 7 SCXI 1122 User Manual Signal Connections Chapter 3 CHO one sample Scanned ple 100 Y times CH1 one sample v CH2 one sample CHO x 100 samples Y Y CH3 one sample CH1 x 100 samples v CH2 x 100 samples v CH3 x 100 samples Y average the samples for each channel average the samples for each channel a Bad technique hardware driven b Good technique software scanning wears out relays 100 times driven scanning saves relay life faster than the software driven sca
63. t via software control These filters are cascaded and are located in two stages This is done to eliminate noise introduced by the isolation amplifier The isolation amplifier fulfills two purposes on the SCXI 1122 module The isolation amplifier converts a small signal riding on a high common mode voltage into a single ended signal with respect to the SCXI chassis ground With this conversion you can extract the input analog signal from a high common mode voltage or noise before it is sampled and converted by the DAQ board The isolation amplifier also amplifies and conditions an input signal which results in an increase in measurement resolution and accuracy The isolation amplifier drives the analog output stage which consists of hardware circuitry which permits several module outputs to multiplex into one DAQ board channel The calibration hardware consists of a software controlled shunt calibration resistor for strain gauge calibration an auto zero calibration for nulling the amplifier offsets and of an EEPROM which holds calibration constants for software correction of gain and offset of the isolation amplifier and of the current and voltage excitations Refer to your software user manual NI DAQ LabVIEW or LabWindows for further details and to the Excitation Calibration section in Chapter 5 Calibration SCXI 1122 User Manual 4 4 O National Instruments Corporation Chapter 4 Theory of Operation Excitation Output Channels In additio
64. table 1 4 calibration equipment requirements 5 1 to 5 2 excitation calibration 4 4 5 4 O National Instruments Corporation gain and offset calibration 5 2 to 5 3 overview 5 1 CH 0 15 signal 3 4 CH 0 15 signal 3 4 configuration See also installation analog configuration 2 3 to 2 5 current loop receivers 2 4 to 2 5 digital signal connections 2 3 jumper settings analog configuration 2 4 digital signal connections 2 3 parts locator diagram 2 2 Configuration Register 4 3 current IEX excitation channel 3 8 current loop receivers 2 4 to 2 5 installing procedure for 2 5 shock hazard related to 2 5 user defined current receiver resistors table 2 4 to 2 5 custom cables 1 5 customer communication xii B 1 D DAQD A signal 3 11 3 12 DIGGND signal 3 11 3 13 digital control circuitry 4 3 digital I O signal connections 3 12 to 3 13 configuration 2 3 digital timing signals 3 13 emulation of SCXIbus communication signals 3 12 SCXIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 specifications and ratings 3 13 documentation conventions used x National Instruments documentation set xi organization of manual ix related documentation xi SCXI 1122 User Manual Index E EEPROM 5 1 environment specifications A 3 equipment optional 1 4 to 1 5 excitation channel signal connections 3 8 to 3 9 connecting quarter bridge strain gauge to channel 0 illust
65. tation channels The SCXI 1122 is a module for signal conditioning of strain gauges RTDs thermistors thermocouples volt and millivolt sources 4 to 20 mA current sources and 0 to 20 mA process current sources The SCXI 1122 can operate in two modes two wire scan mode with all 16 input channels used for input or the four wire scan mode with the eight upper channels configured as sense leads for connecting inputs and the lower eight channels configured as current output channels The SCXI 1122 inputs are multiplexed to a single output which drives a single DAQ board channel The SCXI 1122 operates with full functionality with the National Instruments MIO 16 Lab PC and the SCXI 1200 boards You can use the Lab and PC LPM 16 boards with the SCXI 1122 but these boards cannot scan the module These boards can perform only single channel reads You can multiplex several SCXI 1122s into a single channel thus greatly increasing the number of isolated analog input signals that you can digitize You can add the SCXI 1322 shielded terminal block which has screw terminals to which you can easily attach the input signals to the SCXI 1122 In addition the SCXI 1322 has a temperature sensor for cold junction compensation of thermocouples This cold junction reference CJR is multiplexed with the 16 input channels What Your Kit Should Contain The contents of the SCXI 1122 kit part number 776572 22 are listed as follows Kit Component Part Num
66. tion channel Negative Current Excitation Output signal Positive Current Excitation Output signal input current leakage inches Glossary 2 National Instruments Corporation INTR I O OUTREF P ppm SCANCLK SCXI SDK Glossary Interrupt signal input output meters megabytes of memory Positive Analog Output Channel Number signal Negative Analog Output Channel Number signal minutes multifunction I O Master In Slave Out signal Master Out Slave In signal normal mode rejection nonreferenced single ended input Output Reference signal parts per million resistor random access memory bias resistor bias resistor resistor capacitor filter strain gauge nominal resistance shunt resistor referenced single ended input Reserved bit signal resistance temperature detector Real Time System Integration Scan Clock signal Signal Conditioning eXtensions for Instrumentation bus Software Developer s Kit National Instruments Corporation Glossary 3 SCXI 1122 User Manual Glossary S SENSE SENSE SERCLK SERDATIN SERDATOUT SLOTOSEL SNR SPICLK T TEMP TEMP SCXI 1122 User Manual seconds Negative Voltage Sense signal Positive Voltage Sense signal Serial Clock signal Serial Data In signal Serial Data Out signal Slot 0 Select signal signal to noise ratio Serial Peripheral Interface Clock signal Temperature Sensor Reference signal Temperature Sensor Output signal volts
67. ts This information helps us provide quality products to meet your needs Title SCXI 1122 Register Level Programmer Manual Part Number 340696 01 Please indicate your reasons for obtaining the register level programmer manual Check all that apply O National Instruments does not support your operating system or programming language Ol You are an experienced register level programmer who is more comfortable writing your own register level software O Other Please explain Thank you for your help Name Title Company Shipping Address Street Address Not P O Box Phone Mail to Customer Service Department Fax to Customer Service Department National Instruments Corporation National Instruments Corporation 6504 Bridge Point Parkway 512 794 5794 Austin TX 78730 5039 Documentation Comment Form National Instruments encourages you to comment on the documentation supplied with our products This information helps us provide guality products to meet your needs Title SCXI 1122 User Manual Edition Date September 1999 Part Number 320516B 01 Please comment on the completeness clarity and organization of the manual If you find errors in the manual please record the page numbers and describe the errors Thank you for your help Name Title Company Address Phone Mail to Technical Publications Fax to Technical Publications National Instruments Corporation National Instruments Corporation 1
68. unts across the strain gauge between the VEX and the CH this resistor is socketed to permit you to change its value to meet your requirements If you are performing several strain measurements you can enable the shunt calibration then proceed with scanning all of the channels of interest When you have completed your check you can disable the shunt calibration and proceed with your measurement Notice that when you are either enabling or disabling the shunt calibration resistor you must wait 1 s if you have selected 4 Hz bandwidth or 10 ms if you have selected 4 KHz bandwidth before making your measurement to permit the system to settle Finally to determine the effect of the shunt resistor on your measurement follow the procedure below Assuming a quarter bridge strain gauge configuration with a gauge factor of GF 2 the equivalent strain change the Rscar shunting resistor introduces is 199 This is determined as follows 1 Determine the change the shunting resistor causes using the following formula V exR RscaL R Vex Rscar R Rscar t Rg 2 V change 2 Using the appropriate strain gauge strain formula and assuming that you have no static voltage determine the equivalent strain that the RscA resistor should produce For example if your SCXI system is configured with RscaL 301 KQ a quarter bridge 120 strain gauge with a gauge factor of GF 2 Vex 3 333 V and R 120 Q the following result occurs V c
69. ustration 3 10 pin equivalences SCXTIbus to SCXI 1122 rear signal connector to DAQ board table 3 13 R rear signal connector analog output signal connections 3 11 to 3 12 digital I O signal connections 3 12 to 3 13 pin assignments illustration 3 10 O National Instruments Corporation Index SCXIbus interface 4 3 SCXTIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 signal descriptions 3 11 register level programming 1 4 registers Address Handler Register 4 3 Configuration Register 4 3 Module ID Register 2 3 4 3 Status Register 2 3 4 3 relays avoiding mechanical wear 3 7 to 3 8 illustration 3 8 life expectancy 3 7 resistors See current loop receivers S SCANCLK signal 3 11 3 13 SCXI 1122 block diagram 4 2 features 1 1 kit contents 1 1 major components 4 3 optional equipment 1 4 to 1 5 purpose 1 1 software programming choices 1 2 to 4 unpacking 1 5 SCXIbus connector 4 3 SCXIbus interface 4 3 SCXTIbus to SCXI 1122 rear signal connector to DAQ board pin equivalences table 3 13 SENSE signal 3 4 4 5 SENSE signal 3 4 4 5 SERCLK signal 3 11 3 12 SERDATIN signal 3 11 3 12 SERDATOUT signal 2 3 3 11 3 12 signal connections digital signal connections 2 3 front connector AC coupled signal connection with high common mode voltage illustration 3 7 analog input channel signal connections 3 5 to 3 8 avoiding relay wear illustration
70. y that your offsets gain errors and excitation errors do not exceed the ranges listed in Table 5 1 Table 5 1 Maximum Allowable Error Ranges All gains 2 Offset at G 0 01 40 mV Offset at G 0 02 40 mV Offset at G 0 05 50 mV Offset at G 0 1 50 mV Offset at G 0 2 50 mV Offset at G 0 5 50 mV Offset at G 1 40 mV Offset at G 2 40 mV Offset at G 5 50 mV Offset at G 10 50 mV Offset at G 20 50 mV Offset at G 50 50 mV Offset at G 100 60 mV Offset at G 200 70 mV Offset at G 500 100 mV Offset at G 1 000 200 mV Offset at G 2 000 400 mV Current excitation 3 Voltage excitation t1 SCXI 1122 User Manual 5 4 National Instruments Corporation Appendix A Specifications This appendix lists the specifications for the SCXI 1122 These are typical at 25 C unless otherwise stated Analog Input Input Characteristics Number of channels 16 differential 8 4 wire software selectable Input signal ranges Module Gain Max Module Range Software Selectable 10 V 250 VDC or Vrms 250 V 200 V 100 V 50 V 20 V 10 V 5 V 2 V 1 V 500 mV 200 mV 100 mV 50 mV 20 mV 10 mV 5 mV Input coupling DC Max working voltage signal common mode Overvoltage protection Protected terminals Each input should remain within 480 Vrms of ground and within 250 Vrms of any other channel 250 Vrms powered on 250 V powered off CH 0 15 gt IEX IEX VEX VEX

SCXI-1122 User Manual - National Instruments

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