National Instruments SC-2040 User's Manual
Contents
1. iSS 4 3 Track and Hold VECINA 4 3 Triggering from the DAQ Board eese 4 4 External PIP SSNS uu id oe Yer Metri oS arte asi qoe E Pep aer ose tese 4 5 Output C ODnnectlOn uiis erede ee NR ariadna ciencia 4 6 lower Supply asi ote A DK RARO CUR Lok TRU Het 4 6 Chapter 5 Calibration Procedures ooo eon oO B photo NU ifl aeo metu 5 1 Software Callbratiueciu tr e aites 5 1 Offs t Adj stment eren etate E aS 5 1 Gain Adjustment iste Gud e Ga ERR OS PHI er aA pU 5 2 LANG ary Adjustments di do lisa 5 2 Hardware Calibrat n eid tette 5 2 Appendix A SDECHITCALHOHS a e e ate Ret S AD A Met essel s A 1 Appendix B Customer Communication 7 4 eese B 1 Gl ssar NCC Glossary 1 liri cU O atn Nog Index 1 SC 2040 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 4 1 Figure 4 2 Figure 4 3 Figure 4 4 Table 2 1 Table 2 2 Table 2 3 Table 2 4 Table 2 5 Table 2 6 Table 2 7 Table 2 8 Table Table Table 5 1 3 1 Table 3 2 3 3 Contents Figures The Relationship between the Programming Environment NI DAQ and Your Hardware IAA 1 3 SC 2040 Parts Locator Diarias 2 2 9C 2040 O Connectors J11 and Jl cinc eid tte 3 2 56 2040 Signal BOULDBE sto citer erm oe tS tale reves la pisas 3 6 Ground Refe2. e SC 2040 User Manual e 1 0 2 0 5 0 or 10 0 m SH6868 or R6868 cable Detailed specifications of the SC 2040 are in Appendix A Specifications O National Instruments Corporation 1 1 SC 2040 User Manual Introduction Chapter 1 Software Programming Choices Your SC 2040 kit does not include software There are four options to choose from when programming your National Instruments DAQ and SCXI hardware You can use LabVIEW LabWindows NI DAQ or register level programming software The SC 2040 works with LabVIEW for Windows LabVIEW for Macintosh LabWindows for DOS LabWindows CVI for Windows NI DAQ software for PC compatibles and NFLDAQ software for Macintosh 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 DAQ hard
3. 120 ppm C 150 ppm C 200 ppm C SC 2040 User Manual Specifications Amplifier Characteristics Input impedance Normal powered on Input bias current Input offset current CMRR Output range Dynamic Characteristics Bandwidth System noise Noise spectral density Input noise gain 1 Output noise Slew rate SC 2040 User Manual Appendix A 100 GQ in parallel with 20 pF 100 pA 10 mA max 10 pA dB min amd tp Gain 1 70 dB min 90 dB typ Gain 10 87 dB min 104 dB typ Gain gt 100 100 dB min 110 dB typ 10 V Gain 3 dB Band width 175 u Vrms 50 uVrms 45 uVrms 40 uVrms 35 uVrms 33 uVrms 30 uVrms 29 uVrms 27 uVrms 12 nV VHz 85 nV NHz 8 V us A 2 O National Instruments Corporation Appendix A S H Characteristics Stability Recommended warm up time Offset temperature coefficient Gain temperature coefficient Power Requirement 5 VDC 410 96 Total power dissipation Physical Dimensions I O connectors Input Output Environment Operating temperature Storage temperature Relative humidity O National Instruments Corporation Specifications 0 012 0 003 0 0015 0 00076 Track mode acquisition time Hold mode lus settling time 5 mV 10 mV s 250 ns 50 ns Hold step Droop rate Aperture time Interchannel skew 15 min 10 150 gain UV C Gain Max DIP switch Gain Tempco selectable 25 ppm C 25 ppm
4. 5 external digital signal inputs 3 11 illustration 4 6 theory of operation 4 5 to 4 6 U unity gain position table 2 5 unpacking the SC 2040 1 4 SC 2040 User Manual Index 4 O National Instruments Corporation
5. C 45 ppm C 60 ppm C 80 ppm C 100 ppm C 120 ppm C 150 ppm C 200 ppm C 800 mA 4W 1 8 by 7 9 by 4 9 in 4 6 by 20 1 by 12 4 cm 20 screw terminals 50 pin male ribbon cable rear connector 68 pin male ribbon cable rear connector 0 to 50 C 55 to 150 C 5 to 90 noncondensing A 3 SC 2040 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 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 Technical support fax 800 328 2203 512 794 5678 Branch Offices Phone Number Australia 03 879 9422 Austria 0662 435986 Belgium 02 757 00 20 Denmark 45 76 26 00 Finland 90 527 2321 France 1 48 14 24 00 Germany 089 741 31 30 Italy 02 48301892 Japan 03 3788 1921 Netherlands 03480 33466 Norway 32 848400 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 20 51 51
6. Calibration Software calibration is very simple Depending on your accuracy requirements you may want to perform only offset adjustment offset and gain adjustments or offset gain and linearity adjustments Offset Adjustment Offset adjustment requires you to apply an input signal of zero to the channel to be calibrated Zero input can mean shorting the board inputs to zero or it can mean applying zero excitation to the transducer being used In the former case you can remove only board and DAQ board offset in the latter case transducer offset 1s removed as well In either case measurements are taken with the zero input signal Average these measurements to reduce uncertainty This average represents the offset Next subtract the offset from all subsequent measurements Notice that offset changes with gain thus during calibration set the channel to the gain at which the subsequent measurements will be taken O National Instruments Corporation 5 1 SC 2040 User Manual Calibration Procedures Chapter 5 Gain Adjustment Gain adjustment requires you to apply two different input signals One of the two points is typically zero because zero is easy to generate with a high degree of accuracy The other should be near full scale either a DC voltage from a precision calibrator or a voltage generated by applying a known excitation to the transducer being used Of course you should generate both signals zero and full scale from the same
7. Corporation common mode input range 3 10 to 3 11 exceeding differential and common mode ranges warning 3 10 floating AC coupled signal connection illustration 3 10 ground offset AC coupled signal connection illustration 3 9 ground referenced AC coupled signal connection illustration 3 9 referencing analog ground to DAQ board note 3 8 analog input ranges 3 10 to 3 11 DC coupled inputs 3 7 to 3 8 floating signal connection illustration 3 8 ground referenced signal connection illustration 3 7 leaving connector J5 disconnected note 3 7 B block diagram of SC 2040 4 2 board configuration See configuration C calibration procedures hardware calibration 5 2 to 5 4 calibration component identification table 5 3 steps for 5 3 to 5 4 overview 5 1 software calibration gain adjustment 5 2 linearity adjustment 5 2 offset adjustment 5 1 CH 0 7 signal table 3 3 channel gain selection gain switches for each channel table 2 6 Index 1 SC 2040 User Manual Index procedure for 2 6 to 2 7 switch settings table 2 7 table 2 5 channel input mode table 2 5 CH 0 7 signal table 3 4 common mode input range 3 10 to 3 11 configuration channel gain selection gain switches for each channel table 2 6 procedure for 2 6 to 2 7 switch settings table 2 7 table 2 5 channel input mode table 2 5 DAQ board ground isolation selection procedure for 2 6 table 2 4
8. Monitoring Signal Outputs You can use connector J11 to monitor the signals being sent to and from the MIO 16E board Figure 4 3 shows a sampled analog signal as the SC 2040 channel output You can also monitor the state of the SC 2040 through line PFI7 STARTSCAN A high level on PFI7 STARTSCAN indicates the SC 2040 is in hold mode while a low level indicates that the SC 2040 is in track mode Other Connection Considerations Refer to the sections titled Analog Input Signal Connections and Cabling and Field Wiring in Chapter 3 of your MIO 16E board user manual for additional signal connection information O National Instruments Corporation 3 11 SC 2040 User Manual Chapter 4 Theory of Operation This chapter contains a functional overview of the SC 2040 board and explains the operation of each functional unit making up the SC 2040 Functional Overview The SC 2040 consists of eight channels each one comprising an instrumentation amplifier with DIP switch programmable gains of 1 10 100 200 300 500 600 700 or 800 and a track and hold amplifier The analog inputs are overvoltage protected The DAQ board or a user supplied external trigger switches the SC 2040 between hold mode and track mode as desired All eight channels are simultaneously placed in hold mode The block diagram in Figure 4 1 illustrates the key functional components of the SC 2040 O National Instruments Corporation 4 1 SC 2040 User Manual Theory of Operat
9. SCXI RTSI self calibration messaging and acquiring data to extended memory SC 2040 User Manual 1 2 O National Instruments Corporation Chapter 1 Introduction NI DAQ also internally addresses many of the complex issues between the computer and the DAQ hardware 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 Macintosh or PC or PC Macintosh or Sun SPARCstation Sun SPARCstation Sun SPARCstation NI DAQ Driver Software DAQ or Personal SCXI Hardware coe Workstation Figure 1 1 The Relationship between the Programming Environment NI DAQ and Your Hardware The National Instruments PC AT MC EISA DAQCard and DAQPad Series DAQ hardware is 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 AT MIO 16 together with other PC AT MC EISA DAQC
10. U K 0635 523545 O National Instruments Corporation B 1 Fax Number 03 879 9179 0662 437010 19 02 757 03 11 45 76 71 11 90 502 2930 1 48 14 24 14 089 714 60 35 02 48301915 03 3788 1923 03480 30673 32 848600 91 640 0533 08 730 43 70 056 20 51 55 0635 523154 SC 2040 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 problem include the configuration forms from their user manuals Include additional pages if necessary Name Company Address Fax Phone Computer brand Model Processor Operating system 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 SC 2040 Hardware and Software Configurati
11. in handling the board take the following precautions e Ground yourself via a grounding strap or by holding a grounded chassis such as a computer chassis Touch the antistatic package to a metal part of your computer chassis before removing the board from the package e Remove the board from the package and inspect the board for loose components or any other sign of damage Notify National Instruments if the board appears damaged in any way Do not install a damaged board into your computer e Never touch the exposed pins of connectors SC 2040 User Manual 1 4 O National Instruments Corporation Chapter 2 Configuration and Installation This chapter describes the configuration and installation of your SC 2040 The topics discussed are switch and jumper configuration connection of the SC 2040 to the MIO 16E and the power on sequence for your SC 2040 configuration Board Configuration The SC 2040 has 10 jumpers eight DIP switches and one slide switch that you use to configure the board These switches and jumpers are shown in Figure 2 1 O National Instruments Corporation 2 1 SC 2040 User Manual Chapter 2 Configuration and Installation e qp uip9 cin LMS Y9MS bir DEN SIWNDIS 0 438 UND 8 Y CS Peoippospegds NOUIS SNY AA O LX Y YOdo SAn ak T o DE bic A etera N90 La 9 Jo Djs IS i PES y 000000000 vad Y Y Y aot o ooon Se eo T E yO ol I oO D ae o 00000000000000000 9
12. must turn on power to the SC 2040 before turning on the computer Similarly you must turn off power to the SC 2040 after turning off the computer The red LED labeled DS1 indicates when power is applied to the board SC 2040 User Manual 2 6 O National Instruments Corporation Chapter 3 Signal Connections This chapter describes the signal connections to the SC 2040 board and cable wiring I O Connector Pin Description Warning Connections that exceed any of the maximum ratings of input or output signals on the MIO 16 can result in damage to the MIO 16 board and to the personal computer This includes connecting any power signals to ground and vice versa National Instruments is not liable for any damages resulting from any such signal connections Corresponding signals on connectors J11 and J12 are connected together through the SC 2040 Connector J12 carries the signals to and from the MIO 16E board Use connector J11 to access these signals You can use this connector to monitor these signals using a National Instruments CB 50 for example or you can use this connector to connect to other DAQ accessories Figure 3 1 shows these connectors O National Instruments Corporation 3 1 SC 2040 User Manual Signal Connections Chapter 3 NINININ TRIN ININMITNI M oO o 49 o m o oroj j o co N o a ajaja aja aja DID DID D o Co ilo1 o oo c o M al N o N Pblinolafala alaj aia aj o o N o ajo uxjo o o 48 0 wo oy N
13. oo 34 es 39 e 32 es ar s 30 6 29 663 280 6l er 61 26 eo 25 5 a ss as s 22 ss a ss 20 ss pig 59 08 s2 e so 05 49 i ss a 47 2 4e pa ss de 4 gt NE 9 e so IES ES 3 37 2 3 i as A Breakout Connector J11 B I O Connector J12 Figure 3 1 SC 2040 I O Connectors J11 and J12 Table 3 1 lists the pin assignments for the breakout connector J11 and the I O connector J12 on the SC 2040 and the corresponding and MIO 16E Series signal names SC 2040 User Manual 3 2 O National Instruments Corporation Chapter 3 Signal Connections Table 3 1 Pin Assignments for Connectors J11 and J12 Breakout Connector J11 SC 2040 MIO 16E Series I O Connector J12 Pin Numbers Signal Names Signal Names Pin Numbers AIGND AIGND 24 27 29 32 56 59 64 67 ACHO ACHO AIGND ACH8 ACHI ACHI AIGND ACH9 ACH2 ACH2 AIGND ACHIO ACH3 ACH3 AIGND ACHII ACHA ACH4 AIGND ACHI2 ACH5 ACHS5 AIGND ACH13 ACH6 ACH6 AIGND ACH14 ACH7 ACH7 AIGND ACH15 NC AISENSE NC DACOOUT NC DACIOUT 21 NC EXTREF 20 NC AOGND 54 55 DGND DGND 4 7 9 12 13 15 18 35 36 39 44 50 53 NC DIOO 52 NC DIO4 19 NC DIO1 17 NC DIOS 51 NC DIO2 49 NC DIO6 16 NC DIO3 47 NC DIO7 48 45V 45V 8 14 NC SCANCLK 46 NC EXTSTROBE 45 NC PFIO TRIGI 11 NC PFII TRIG2 10 TRIG PFI2 CONVERT 43 NC PFI3 GPCTR1_SOURCE 42 NC PF
14. source Take measurements on both signals and compute separate averages Then combine the averages with the known input signals to generate linear correction factors for all subsequent measurements Specifically if the input X yields measurement x and the input Y yields measurement y then you should process measurement z as shown in the following equation to yield the corrected measurement Z O X x y x Z X Linearity Adjustment The SC 2040 seldom needs linearity adjustment because its linearity is quite good especially at low gains Linearity error is often caused by the nonlinearity of the DAQ board you use If necessary the method described previously for correcting gain and offset error may be extended to include linearity by taking more points along the transfer function and processing the subsequently acquired data according to a polynomial fit of the calibration points Alternatively and preferably for DAQ boards with no more than 12 bits of resolution you can determine the nonlinearity of the system on a code by code basis and you can subtract the error of each code from any measurement that returns that value This method has the advantage of correcting differential as well as integral linearity errors However this method may be time consuming If time permits you may determine the nonlinearity of your system on a code by code basis with even higher resolution DAQ boards Describing methods of measuring system nonl
15. to keep the SC 2040 analog SHLD OFF ground isolated from the metal standoffs in the corners of the board factory setting SHLD ON SHLD ON position Place the jumper in this position to connect the SC 2040 analog ground to the metal standoffs or to a rack mount kit which may provide shielding for the SC 2040 SHLD OFF SHLD ON Table 2 3 DAQ Board Ground Isolation Selection AIGND AIGND position Use this setting if you are using a MIO 16E DAQ board Place the jumper in this position to keep the SC 2040 digital ground and analog grounds isolated factory setting AIGND DGND position Place the jumper in this position to connect the SC 2040 analog ground to digital ground SC 2040 User Manual 2 4 O National Instruments Corporation Chapter 2 Configuration and Installation Table 2 4 Channel Gain Selection Unity gain position For unity gain gain 1 open all the switches by pushing down the OFF end of the switches factory setting The unity gain position has the number side up Gain Table Other gains Refer to Supplementary Configuration Information later in the chapter and the gain table on the board itself Table 2 5 Channel Input Mode A B position Use this setting for connecting ground referenced signals to the SC 2040 factory setting B C position Use this setting for connecting floating non ground referenced sources A 100 kQ resistor is connect
16. 20090 JlOD000000090 BII 020 San eg 2 IN Lori e xpogi e oo ppa nana Epa A 1299009055 0000000000000000 o0000000O0O0O0OO0O0O0O00 Sa i 2 ava e ade 000000059 0000000000000 d z 3 9 z 2 re e sii fra y Y I o Z A A c m z A Hm d fon en Frei 66506050000 dagy z e 8z YZ 1Z Ll Seuowws 1 6 9 zn dig uy CCH 618 O National Instruments Corporation Figure 2 1 SC 2040 Parts Locator Diagram 2 2 SC 2040 User Manual Chapter 2 Configuration and Installation The SC 2040 has one switch that controls whether the board is powered from an external supply or from the MIO 16E board Furthermore two jumpers control how the board is shielded and grounded Additionally there are eight sets of switches and jumpers that configure the gain settings and input modes of the eight SC 2040 channels Table 2 1 Power Supply Selection INT position Use this setting SW1 to configure the SC 2040 to INT draw power through the MIO 16E board factory EXT setting A Internal Power EXT position Use this setting to draw 5 V power INT from an external supply connected to connector J13 EXT SW1 B External Power O National Instruments Corporation 2 3 SC 2040 User Manual Configuration and Installation Chapter 2 Table 2 2 Shield Selection SHLD OFF position Place the jumper in this position
17. C 2040 into track mode The MIO 16E board uses line PFI7 STARTSCAN to indicate to the SC 2040 whether it should track the input signals or hold them at a constant level A logic zero low level on PFI7 STARTSCAN indicates track mode while a logic one high level indicates hold mode as indicated in Figure 4 3 SC 2040 User Manual 4 4 National Instruments Corporation Chapter 4 Theory of Operation Differential Channel Input A NNI NJ PFI7 track hold hold hold track SC 2040 Channel Output PEN MA Y baa Conversion I I tbaQ Conversion DAQ board is scanning Figure 4 3 MIO 16E Controlled Triggering External Triggering This section applies to you only if you are triggering the board from an external signal connected to J10 You can connect an external trigger to place the SC 2040 into hold mode on command A rising edge on the external trigger signal places the SC 2040 into hold mode and alerts the MIO 16E board to start scanning the SC 2040 outputs After the MIO 16E board has acquired data from all of the channels it returns the SC 2040 to track mode The external trigger signal is a digital input and must conform to digital logic levels Because the SC 2040 track and hold circuitry must re acquire the input signals at the conclusion of each hold mode operation the external trigger source should not return the SC 2040 to hold mode until after the SC 2040 has had time to re acquire the signals
18. I4 GPCTR1_GATE 41 NC GPCTR1_OUT 40 NC PFIS UPDATE 6 NC PFI6 WFTRIG 5 TRACK HOLD PFI7 STARTSCAN 38 NC PFI8 GPCTRO_SOURCE NC PFI9 GPCTRO_GATE NC GPCTRO_OUT NC FREQ OUT l an signals labeled NC are unused by the SC 2040 National Instruments Corporation 3 3 SC 2040 User Manual Signal Connections Chapter 3 Signal Connection Description Table 3 2 Input Connectors Signal Summary Connector Signal Name Description J5 AIGND Analog Input Ground These inputs provide a bias current return point for AC coupled signals J1 J2 J3 J4 CH lt 0 7 gt Positive Inputs These inputs are the positive signal inputs for J6 J7 J8 JO channels 0 through 7 J1 J2 J3 J4 CH lt 0 7 gt Negative Inputs These inputs are the negative signal inputs for J6 J7 J8 JO channels 0 through 7 J10 J13 DGND Digital Ground These inputs provide the reference for all digital signals and the reference for the 5 V power source J10 TRIG Trigger This input which is connected directly to the PFI2 pin on connectors J11 and J12 is a trigger input for the MIO 16E A low to high transition on TRIG alerts the MIO 16E to place the SC 2040 into hold mode and start acquiring data 5 VDC Source When external power is selected this input provides DC power for the SC 2040 from an e
19. SC 2040 User Manual Eight Channel Simultaneous Sample and Hold Accessory September 1994 Edition Part Number 371191A 01 Copyright 1994 National Instruments Corporation All Rights Reserved National Instruments Corporate Headquarters 6504 Bridge Point Parkway Austin TX 78730 5039 512 794 0100 Technical support fax 800 328 2203 512 794 5678 Branch Offices Australia 03 879 9422 Austria 0662 435986 Belgium 02 757 00 20 Canada Ontario 519 622 9310 Canada Qu bec 514 694 8521 Denmark 45 76 26 00 Finland 90 527 2321 France 1 48 14 24 24 Germany 089 741 31 30 Italy 02 48301892 Japan 03 3788 1921 Netherlands 03480 33466 Norway 32 848400 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 20 51 51 U K 0635 523545 Limited Warranty The SC 2040 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 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 th
20. The acquisition times for the SC 2040 at various accuracies are given in Appendix A Specifications The external trigger is connected directly to signal PFI2 on the DAQ board A rising edge alerts the DAQ board to place the SC 2040 into hold mode The DAQ board then begins scanning the channels After the scanning process is complete the board returns the SC 2040 to track mode using PFI7 STARTSCAN Notice that additional rising edges from the external trigger are ignored while the MIO 16E is scanning Figure 4 4 illustrates the external triggering process O National Instruments Corporation 4 5 SC 2040 User Manual Theory of Operation Chapter 4 Differential Channel Input 29280724 PFI2 external trigger ME HE PFI7 track hold hold track hold track SC 2040 Channel Output E a SS iPAQ Conversion iPAQ Conversion DAQ board is scanning Figure 4 4 External Triggering Output Connection The output of every channel is connected to the 68 pin rear signal connector and the 50 pin supplemental I O connector The 68 pin connector carries signals to and from the DAQ board and also provides 5 V power if selected by the power switch The corresponding pins of the 50 pin connector are tied to those of the 68 pin connector so that you can monitor these signals on the 50 pin connector The pin connections of these connectors are given in Chapter 3 Signal Connections Power Supply The SC 2040 contains an onboard power swi
21. acquire data The track mode acquisition time refers to how long it takes the T H amplifiers to O National Instruments Corporation 4 3 SC 2040 User Manual Theory of Operation Chapter 4 find the inputs again after having been in hold mode Therefore this delay indicates how long the SC 2040 must remain in track mode before it is ready to re enter hold mode Returning the SC 2040 to hold mode before the track mode acquisition delay has elapsed will cause the SC 2040 to hold erroneously Figure 4 2 illustrates these timing concerns Typical hold mode settling times and track acquisition times for 12 bit and 16 bit accuracies are given in Appendix A Specifications differential channel input T H output l hold setting I track acquisition time time track hold signal l eri track hold track hold Figure 4 2 T H Amplifier Hold Settling Time and Track Acquisition Time Triggering from the DAQ Board This section applies to you only if you are triggering the SC 2040 from the MIO 16E board Note No signal should be connected to connector J10 for MIO 16E triggering You can place the SC 2040 into hold mode on command using the MIO 16E DAQ board You must either program the MIO 16E board for this purpose or use the NI DAQ software included with your MIO board After placing the SC 2040 into hold mode the MIO 16E board performs data acquisition and conversion Once this process is complete the MIO 16E board releases the S
22. act 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 O National Instruments Corporation xi SC 2040 User Manual Chapter 1 Introduction This chapter describes the SC 2040 lists what you need to get started with your SC 2040 describes the optional software and optional equipment and explains how to unpack your SC 2040 About the SC 2040 The SC 2040 is an eight channel simultaneously sampling differential amplifier for the National Instruments MIO 16E Series DAQ boards Each channel provides DIP switch selectable gain followed by a track and hold amplifier The track and hold amplifiers sample all the inputs at the same time which is useful for preserving interchannel phase relationships The MIO 16E can trigger the track and hold amplifiers or you can supply an external trigger source Note When a board is referred to without an AT prefix that is MIO 16E the reference applies to the AT versions of that board The SC 2040 is a circuitboard assembly that is placed on a workbench or mounted in a 19 in rack You can configure the SC 2040 to draw power from the MIO 16E board or from an external 5 V supply A red LED indicates when the board is powered on Input signal leads are attached at screw terminals What You Need to Get Started To set up and use your SC 2040 you will need the following components e SC 2040 board
23. age within their common mode input range caused by ground potential differences between the signal source and the board In addition the amplifiers can reject common mode noise pickup in the leads connecting the signal sources to the SC 2040 board However you should be careful to minimize noise pickup The common mode rejection of the instrumentation amplifiers decreases significantly at high frequencies The amplifiers do not reject normal mode noise The common mode input range of the SC 2040 instrumentation amplifiers is defined as the magnitude of the greatest common mode signal that can be rejected Thus the common mode input range for the SC 2040 depends on the gain and size of the differential input signal Vaig V in Vin The exact formula for the permissible common mode input range is as follows Vem allowed t 12 V Sr Thus with a differential voltage of 10 V and a gain of G 1 the maximum possible common mode voltage would be 7 V The same range would apply for a differential input of 100 mV and a gain of 100 The range increases to 12 V for zero differential input voltage The actual common mode voltage available at the input is measured with respect to the SC 2040 ground and can be calculated by the following formula 2 V cm actual SC 2040 User Manual 3 10 O National Instruments Corporation Chapter 3 Signal Connections where V is the signal at the positive input INO through IN7 and V
24. ard and DAQPad Series DAQ 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 interfaces 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 The National Instruments SB Series DAQ boards are packaged with NI DAQ software for Sun which comes with a language interface for ANSI C National Instruments Corporation 1 3 SC 2040 User Manual Introduction Chapter 1 Register Level Programming There are no register level programming concerns for the SC 2040 When using the SC 2040 only the MIO 16E Series board needs to be programmed Refer to your MIO 16E board manual for further information on register level programming Optional Equipment Contact National Instruments to order the following optional equipment e CB 50 I O connector 50 screw terminals with 0 5 or 1 0 m cable Single or double height rack mount kit with acrylic plastic cover Single or double height rack mount kit with metal wraparound cover Unpacking Your SC 2040 board is shipped in an antistatic package to prevent electrostatic damage to the board Electrostatic discharge can damage several components on the board To avoid such damage
25. ated If necessary repeat steps 5 and 6 until the offset is calibrated at both gains 8 Repeat steps 5 through 7 for the additional channels you want to calibrate There is no calibration interdependence among the channels 9 Replace the rack mount chassis cover if used SC 2040 User Manual 5 4 O National Instruments Corporation Appendix A Specifications This appendix lists the specifications for the SC 2040 These are typical at 25 C unless otherwise stated The operating temperature range is 0 to 50 C Analog Input Input Characteristics Number of channels 8 differential Board Gain Hardware Selectable Board Range Max Output Range 10 V Input signal ranges 10 V 1V 100 mV 50 mV 33 3 mV 20 mV 16 67 mV 14 29 mV 12 5 mV Input coupling DC Max working voltage signal common mode Overvoltage protection Average of 2 inputs should remain within 7 V of ground 30 V powered on 15 V powered off Inputs protected ACH lt 0 7 gt Transfer Characteristics Offset error Pregain error after calibration 100 uV max Postgain error after calibration 2 mV max Max Nonlinearity Max Gain Error Max Gain Tempco Gain DIP switch selectable Gain error and nonlinearity 0 05 25 ppm C National Instruments Corporation A 1 0 1 0 2 10 4 0 3 0 6 1 0 0 2 41 5 0 1 2 0 0 3 43 0 25 ppm C 45 ppm C 60 ppm C 80 ppm C 100 ppm C
26. ated to have total offset referred to output of less than 2 mV at low gains Table 5 1 shows which pots to adjust for each type of offset for each channel and which DIP switch selects the gain for each channel Refer to the parts locator diagram in Chapter 2 Configuration and Installation to determine the location of each component Table 5 1 Calibration Component Identification Output Offset Adjust Input Offset Adjust Gain DIP Switch RI R4 U2 A complicating factor in the calibration of the board is that the output offset is not the same in track mode as in hold mode This difference is because of a phenomenon known as hold step in which a small amount of charge is transferred to the track and hold amplifier hold capacitor during the transition from track mode to hold mode This charge transfer slightly changes the voltage at the output of the track and hold amplifier The magnitude of the hold step on the SC 2040 is approximately 5 mV enough to make it necessary to calibrate output offset in hold mode rather than track mode You may calibrate input offset without switching the board to hold mode To calibrate the SC 2040 board the following steps are required 1 If you are using a rack mount kit remove the cover to expose the DIO switches and jumpers Connect the board so that the pots and DIP switches are readily accessible 2 Short each input of the board to ground At low gains more alternatives exist to serve as a sho
27. ble value use software to average a few hundred readings After you have measured and recorded the offset remove the short circuits and reconnect the board 5 Measure the output of the first channel with its gain set to one and adjust its output offset pot until the output is close to zero At this gain most of the board offset is due to output offset The input offset adjustment has minimal effect Set the DAQ board to read the channel Acquire the data averaging as in step 4 Adjust the output offset pot until the difference between the measured offset and the DAQ board offset is close to zero There is no need to adjust it perfectly because the input offset adjustment in the next step might make a slight change in the measured gain of one offset 6 Measure the output of the same channel with its gain set to 500 and adjust its input offset pot until the output is close to zero At this gain the input offset adjustment has the dominant effect Acquire the data and average as before Adjust the input offset pot until the difference between the measured offset and the DAQ board offset is close to zero Again it is not necessary to adjust the input offset perfectly because there will be a slight interdependence between the two offsets 7 Repeat step 5 adjusting the offset as carefully as desired Then repeat step 6 adjusting the offset as carefully as desired Switch back to a gain of one to ensure that the low gain offset is still calibr
28. coupled inputs 3 10 to 3 11 analog input ranges 3 10 to 3 11 DC coupled inputs 3 7 to 3 8 connections exceeding maximum ratings warning 3 1 digital signal inputs 3 11 input connectors signal summary table 3 4 monitoring signal inputs 3 11 other connection considerations 3 11 output connectors J11 and J12 signal summary table 3 4 to 3 5 SC 2040 I O connectors J11 and J12 illustration 3 2 signal routing illustration 3 6 signal outputs monitoring 3 11 software calibration See calibration procedures software programming choices LabVIEW and LabWindows application software 1 2 NI DAQ driver software 1 2 to 1 3 SC 2040 User Manual Index register level programming 1 4 specifications analog input amplifier characteristics A 2 dynamic characteristics A 2 input characteristics A 1 S H characteristics A 3 stability A 3 transfer characteristics A 1 environment A 3 physical A 3 power requirements A 3 T technical support B 1 theory of operation analog circuitry 4 2 to 4 6 amplification 4 3 external triggering 4 5 to 4 6 input protection 4 3 output connection 4 6 power supply 4 6 track and hold T H circuitry 4 3 to 4 4 triggering from DAQ board 4 4 to 4 5 block diagram 4 2 functional overview 4 1 track and hold T H circuitry 4 3 to 4 4 TRIG signal description table 3 4 susceptibility to noise 3 11 TRIG PF12 signal table 3 4 triggering from DAQ board 4 4 to 4
29. creates the DC path for the positive input bias current Typical resistor values range from 100 kQ to 10 MO This solution although necessary in this case lowers the input impedance of the channel and introduces an additional offset voltage proportional to the product of the input bias current and the resistor value used The inputs of the SC 2040 have a typical bias current of about 100 pA When you use a 1 MQ resistor the result is 100 uV of offset which is insignificant in most applications However if you use larger valued bias resistors significant input offset may result Lower valued bias resistors will increase loading of the source possibly resulting in gain error SC 2040 User Manual 3 6 O National Instruments Corporation Chapter 3 Signal Connections Figures 3 5 through 3 7 illustrate how to connect AC coupled signals SC 2040 SC 2040 Figure 3 6 Ground Offset AC Coupled Signal Connection O National Instruments Corporation 3 9 SC 2040 User Manual Signal Connections Chapter 3 SC 2040 Figure 3 7 Floating AC Coupled Signal Connection Analog Input Ranges Warning Exceeding the differential and common mode input ranges results in distorted input signals Exceeding the maximum input voltage rating can result in damage to the SC 2040 board and the DAQ board National Instruments is NOT liable for any damages resulting from such signal connections The SC 2040 instrumentation amplifiers can reject any volt
30. d by properly trained and qualified medical personnel and all traditional medical safeguards equipment and procedures that are appropriate in the particular situation to prevent serious injury or death should always continue to be used when National Instruments products are being used National Instruments products are NOT intended to be a substitute for any form of established process procedure or equipment used to monitor or safeguard human health and safety in medical or clinical treatment Contents About This Manu dl c oeste mote pete ima es ix Oreanization of This Manta ix Conventions Used in This Manual cotidianidad AER X The National Instruments Documentation Set sese X Related Documentation o o xi Customer Communication odere e e Pee eL reas xi Chapter 1 A e NI nta erbe tp p 1 1 Abont the SC 2040 coena eub db adea ra fcd a ees e 1 1 What You Need to Get Started oo ente ete erica 1 1 Software Programming Choices stet ise ti ve e deus 1 2 LabVIEW and LabWindows Application Software sees 1 2 NI DAQ Driver Software esses eene nennen nennen entente seen 1 2 Register Level Programming iet eio bora nate eee nena sngensvecwovaadedede 1 4 Optional Eg lpIBetibs 5 ooi crea 1 4 MACK ine a vaca vais SIAE 1 4 Chapter 2 Configuration and Installation sse 2 1 Board CORR ULA ON ads anas uo Tet a ie get Re RU M
31. e TRU e OMEN RIR Pare URINE SERM anes 2 1 Supplementary Configuration Information eene 2 6 Power Supply SeleeuOfo sn eetosse td Neskus ie dues lotes s oas aa ats 2 6 Shield Selection iii 2 6 DAQ Board Ground Isolation Selection esses 2 6 Gan Selection Sie esee de hao Ure foeda cedo educat RARE Cod Def 2 6 Input Mode Selection deos a o 2 7 Tri tall aflOTE 3o endis e ce oasis v ease nds ca att aoe cava mrt edu pire 2 8 Power On Sequence A pde tr eui e gets eaten 2 8 Chapter 3 Signal Connections o oe ocho deu t ieiuna da 3 1 VOY Connector Pin De nea aa true ade de eed ee en ie 3 1 Signal Connection Description eo perderte rd 3 4 Analog Sienal Inputs aot tum fem t a Ho Ra tse IS Ges MINES 3 7 DC Coupied Inputs d oedeud eun edendi pattern dee E De d 3 7 AC UC OUpled SIBI ne eraat toss teet qe e ts Mansur occa bs aeons cose 3 8 Analog Input Ranges eoo ete eb its 3 10 Disital Stenal eii 3 11 Monitoring Signal Outputs ette tst o tana erae ab aee oe een ko ge Ede RAUS 3 11 Other Connection ConsIderatiOlls iie ces dte eote tesa h ee Ur ME era a ue ea deme loce d UR aee pvelua caua nes 3 11 O National Instruments Corporation v SC 2040 User Manual Contents Chapter 4 Theory of O PELO ot meon a en AA es te 4 1 a roe e notus at oma penu M eeah etd es 4 1 PV A A A eed gee Bates 4 3 Input Protection s es bito qa otl Soeur uses Sos case dea e quet eiie RAAS 4 3 Amplification T
32. e information in this manual is accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not c
33. e signals Second the instrumentation amplifiers amplify input signals resulting in an increase in measurement resolution and accuracy Furthermore the amplifiers exhibit low bias currents and good bandwidth even at high gains You can select gains for each channel independently with separate DIP switches Gains are 1 10 100 200 and 500 although gains of 300 600 700 and 800 are available with reduced accuracy See Appendix A Specifications for details on the performance of the instrumentation amplifiers Track and Hold T H Circuitry The track and hold amplifiers operate as simple buffers when in track mode but freeze their outputs when placed into hold mode Because all of the track and hold amplifiers in each SC 2040 board enter hold mode at the same time they implement simultaneous sampling of all channels Simultaneous sampling is useful for preserving phase relationships between channels The track and hold amplifiers are subject to various imperfections which are listed in Appendix A Specifications The most relevant of these performance specifications are the track mode acquisition time and the hold mode settling time as these parameters affect how the DAQ board acquires the data most noticeably through the sampling rate The hold mode settling time refers to how long it takes the T H amplifiers to settle a stable value Thus the hold mode settling time affects how long the DAQ board must wait before attempting to
34. ease 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 6504 Bridge Point Parkway MS 53 02 MS 53 02 Austin TX 78730 5039 512 794 5678 Glossary ACH A D Arms AWG CH CH CMOS cps D A DAQ DC DIN DIP FIFO hex Hz in Lin I O Tout LED LSB MB MSB ppm National Instruments Corporation degrees ohms amperes DAQ board analog input channel number analog to digital amperes root mean square American Wire Gauge Celsius module positive input channel number module negative input channel number complementary metallic oxide semiconductor counts per second digital to analog data acquisition decibels direct current Deutsche Industrie Norme dual inline package first in first out hexadecimal hertz inches input current leakage input current input output output current light emitting diode least significant bit meters megabytes most significant bit parts per million Glossary 1 SC 2040 User Manual Glossary RAM rms S SPI tempco T H UL V VI VIH VIL Vin VoH VoL Vout VAC VDC Vrms SC 2040 User Manual random access memory root mean square seconds serial peripheral interface temperature coefficient trac
35. eaving the jumper in its default position Gain Selection The gain selection switches can select gains of 1 10 100 200 300 500 600 700 and 800 for each channel as shown in Table 2 6 Table 2 6 Gain Switches for Each Channel SC 2040 User Manual 2 6 O National Instruments Corporation Chapter 2 Configuration and Installation To close a switch push down the number side Closing switch A selects a gain of 500 Closing switch B selects a gain of 200 Closing switch C selects a gain of 100 Closing switch D selects a gain of 10 Opening all the switches selects a gain of 1 You can select other gains by closing more than one switch as shown in Table 2 7 Table 2 7 Switch Settings for Gain Selection B and C A A and C A and B A B and C Input Mode Selection Jumpers W2 through WO select the input mode for each channel on the SC 2040 Position A B leaves the negative input of the instrumentation amplifier connected only to the front connector This is the factory default setting Position B C connects the negative input of the instrumentation amplifier to the board analog ground through a 100 KQ resistor This setting is useful for keeping floating or nonground referenced sources from saturating the instrumentation amplifier Table 2 8 shows the input mode jumper and channel selections Table 2 8 Input Mode Selection Jumpers O National Instruments Corporation 2 7 SC 2040 User Manual Configuration and Installat
36. ed from the negative channel input to the SC 2040 analog ground The W3 W9 jumper positions are the same as on W2 O National Instruments Corporation 2 5 SC 2040 User Manual Configuration and Installation Chapter 2 Supplementary Configuration Information Power Supply Selection Set switch SWI to the INT position to connect the SC 2040 power converter to the 5 V lines on the MIO 16E board Set switch SW1 to the EXT position to draw power from an external 5 V power supply connected to J13 The MIO 16E is fused to provide 5 W of power at 5 V and 1 A The SC 2040 consumes nearly all of this available power Therefore if you have other DAQ accessories that you would like to power from the MIO you should switch the SC 2040 to external power and provide an external 5 V power source In external power mode the SC 2040 is fuse limited to 1 A at 5 V Shield Selection If you are using a rack mount kit shield the SC 2040 from unwanted noise by connecting the analog ground on the board to the metal chassis of the rack using jumper W1 When you set W1 to the SHLD ON position the jumper connects the analog ground to the metal standoffs used to mount the board in a rack In the SHLD OFF position the SC 2040 analog ground is isolated from the metal standoffs DAQ Board Ground Isolation Selection You can use jumper W10 to connect the SC 2040 digital and analog grounds If you are using a MIO 16E board you must isolate the grounds by l
37. ents Corporation Chapter 3 Signal Connections Analog Signal Inputs Connect the differential signals to be measured to the screw terminal connectors J1 through J4 and J5 through J9 DC Coupled Inputs Note If all your inputs are DC coupled leave connector J5 disconnected All eight channels have fully differential inputs so the signals you are measuring should be ground referenced If they are not set jumpers W2 through W9 of the nonreferenced channels to position B C to create a DC path for the input bias currents If you do not do this the bias currents of the instrumentation amplifiers of the nonreferenced channels produce stray capacitances resulting in uncontrollable drift and possible saturation Figure 3 3 illustrates how to connect a ground referenced signal Figure 3 3 Ground Referenced Signal Connection O National Instruments Corporation 3 7 SC 2040 User Manual Signal Connections Chapter 3 Figure 3 4 illustrates how to connect a floating signal SC 2040 Figure 3 4 Floating Signal Connection AC Coupled Signals Note For AC coupled signals you must reference the analog ground of your instrumentation to the DAQ board The SC 2040 connector J5 provides the analog reference connecting directly to the MIO 16E board as shown in Figure 3 2 For AC coupled signals set jumpers W2 through W9 to position B C with an external resistor from the positive input channel connected to its negative ground Doing this
38. inearity is beyond the scope of this manual If linearity correction becomes necessary refer to your DAQ board user manual Hardware Calibration There are two potentiometers pots to adjust for each channel These are set at the factory and should not need to be readjusted for most applications The pots adjust input offset voltage and output offset voltage for each of the eight channels Gain error and linearity are not adjustable For detailed specifications of offset gain and linearity error see Appendix A Specifications Input offset is any error voltage that appears to be added to the input signal that is its effect is multiplied by the gain of the instrumentation amplifier Output offset is any error voltage that appears to be added to the output signal that is its effect is independent of the gain of the instrumentation amplifier At a fixed gain these errors are indistinguishable thus it is necessary to switch between gains to properly calibrate the SC 2040 SC 2040 User Manual 5 2 O National Instruments Corporation Chapter 5 Calibration Procedures Your accuracy needs determine how carefully the offsets need to be calibrated A typical requirement might be for total offset referred to output to be less than half of an LSB of the DAQ board being used For example a 12 bit 20 V system has a resolution of 20 V 2 2 4 88 mV Calibration to under 2 mV would thus be sufficient for most applications The SC 2040 is factory calibr
39. input mode selection 2 7 parts locator diagram 2 2 power supply selection procedure for 2 6 table 2 3 shield selection procedure for 2 4 table 2 4 connectors J11 and J12 overview 3 1 pin assignments illustration 3 2 table 3 3 signal routing illustration 3 6 signal summary table 3 4 customer communication xi B 1 D DAQ board ground isolation selection procedure for 2 6 table 2 4 DC coupled inputs 3 7 to 3 8 floating signal connection illustration 3 8 ground referenced signal connection illustration 3 7 leaving connector J5 disconnected note 3 7 DGND signal input connector summary table 3 4 SC 2040 User Manual output connector summary table 3 4 to 3 5 digital signal inputs 3 9 documentation conventions used in manual x National Instruments documentation set x organization of manual ix related documentation xi E environment specifications A 3 equipment optional 1 4 EXT switch position table 2 3 F floating AC coupled signal connection illustration 3 10 floating signal connection illustration 3 8 G gain selection See channel gain selection ground offset AC coupled signal connection illustration 3 9 ground referenced AC coupled signal connection illustration 3 9 ground referenced signal connection illustration 3 7 H hardware calibration See calibration procedures hold mode settling time 4 3 I input connectors signal summary
40. ion Chapter 2 Installation Note You must turn off power to the PC and to the SC 2040 board if the board is externally powered before installing the board or making any connections to it To install the SC 2040 connect the 68 pin ribbon from the MIO 16E I O connector to connector J12 on the SC 2040 The SC 2040 can be mounted in a rack mount chassis using the mounting holes indicated with an arrow on the board in the four corners of the SC 2040 board The SC 2040 is installed You are now ready to install and configure your software If you are using NI DAQ refer to your NI DAQ manual 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 Power on Sequence If the SC 2040 is powered by an external power source you
41. ion Chapter 4 68 Pin I O Connector 50 Pin Breakout Connector Power On External rj c eo 05 D o I x eo q x E External Trigger Input Protection External Track Hold Trigger Figure 4 1 SC 2040 Block Diagram SC 2040 User Manual 4 2 O National Instruments Corporation Chapter 4 Theory of Operation Analog Circuitry The analog input circuitry consists of eight channels with DIP switch programmable instrumentation amplifiers followed by buffered track and hold amplifiers In addition you can include the voltage regulation circuitry and input protection in the analog section Each block is described in the following paragraphs Input Protection The first block an incoming analog signal encounters is the input protection Each input terminal is protected against input voltages up to 15 V powered off and 30 V powered on The input protection consists of a 1 KQ resistor in series with each input line followed by low leakage diodes to the supply rails 15 V Amplification Next in the signal path are the instrumentation amplifiers which fulfill two purposes on the SC 2040 board First the instrumentation amplifiers convert differential input signals into single ended signals referred to the SC 2040 analog ground for input common mode signal rejection With this conversion the SC 2040 can extract the analog input signals from common mode noise voltages before the DAQ board samples and converts th
42. is the signal at the corresponding negative input INO through IN7 Both V and V are measured with respect to the SC 2040 chassis ground Digital Signal Inputs If you are using an external trigger connect the trigger source and the digital reference to screw connector J9 This signal should be in the range 0 to 5 V with switching occurring around 1 5 V Note All digital signals on the SC 2040 are referenced to the 5 V power supply If the MIO 16E supplies power it provides this reference If an external supply provides power it provides this reference through connector J13 A rising edge on the trigger will place the SC 2040 into hold mode and the SC 2040 will return to track mode when the MIO 16E indicates that the data acquisition is complete Although the TRIG signal is a digital signal it is still susceptible to noise particularly at its transitions This noise can cause the SC 2040 to enter hold mode on the wrong edge Two possible sources of noise are interference and reflection The best way to reduce noise corruption is to minimize the distance that the signal must travel Furthermore you can minimize interference by properly shielding the incoming trigger signal You can minimize reflection by ensuring that the impedance of the source of the trigger signal matches the impedance of the cable used to transmit the signal inserting a small resistor about 50 Q in series with the signal source will minimize reflection
43. k and hold Underwriters Laboratory volts virtual instrument volts input high volts input low volts in volts output high volts output low volts out volts alternating current volts direct current volts root mean square Glossary 2 National Instruments Corporation Index Numbers Symbols 5 V signal input connector summary table 3 4 output connector summary table 3 4 to 3 5 A AC coupled inputs 3 8 to 3 11 common mode input range 3 10 to 3 11 exceeding differential and common mode ranges warning 3 10 floating AC coupled signal connection illustration 3 8 ground offset AC coupled signal connection illustration 3 9 ground referenced AC coupled signal connection illustration 3 9 referencing analog ground to DAQ board note 3 8 AIGND AIGND position table 2 4 AIGND DGND position table 2 4 AIGND signal input connector summary table 3 4 output connector summary table 3 4 to 3 5 analog circuitry 4 2 to 4 6 amplification 4 3 external triggering 4 5 to 4 6 input protection 4 3 output connection 4 6 power supply 4 6 track and hold T H circuitry 4 3 to 4 4 triggering from DAQ board 4 4 to 4 5 analog input specifications amplifier characteristics A 2 dynamic characteristics A 2 input characteristics A 1 S H characteristics A 3 stability A 3 transfer characteristics A 1 analog signal inputs 3 7 to 3 11 AC coupled inputs 3 8 to 3 11 O National Instruments
44. l including abbreviations acronyms metric prefixes mnemonics and symbols The ndex contains an alphabetical list of key terms and topics used in this manual including the page where you can find each one O National Instruments Corporation ix SC 2040 User Manual About This Manual Conventions Used in This Manual The following conventions are used in this 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 MIO 16E MIO 16E refers to the National Instruments E Series of MIO 16 DAQ boards 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 Abbreviations acronyms metric prefixes mnemonics symbols and terms are listed in the Glossary The National Instruments Documentation Set The SC 2040 User Manual is one piece of the documentation set for your system You could have any of several types of manuals depending on the hardware and software in your system Use the manuals you have as follows Your DAQ hardware user manuals These
45. manuals have detailed information about the DAQ hardware that plugs into or is connected to your computer Use these manuals for hardware installation and configuration instructions specification information about your DAQ hardware and application hints Software manuals Examples of software manuals you might have are the LabVIEW and LabWindows manual sets and the NI DAQ manuals After you 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 Accessory manuals If you are using accessory products read the terminal block and cable assembly installation guides or accessory board user manuals They explain how to physically connect the relevant pieces of the system together Consult these guides when you are making your connections SC 2040 User Manual x National Instruments Corporation About This Manual Related Documentation The following document contains information that you may find helpful as you read this manual Your DAQ hardware user 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 cont
46. on Chapter 3 Signal Connections Table 3 3 Output Connectors J11 and J12 Signal Summary Continued J11 Pin J12 Pin Signal Name Description 50 pin 68 pin 46 38 TRACK HOLD Track or hold This pin used as an output from the PFI7 STARTSCAN MIO 16E controls whether the SC 2040 is in hold mode or track mode A high level output from the DAQ board places the SC 2040 into hold mode while a low level returns the SC 2040 into track mode With an MIO 16E attached pin 46 on J11 should be used for monitoring purposes only compatibility The remaining pins provide 50 pin compatibility with the 68 pin MIO 16E They can be monitored from connector J11 Refer to Figure 3 1 for pin locations and to Chapter 3 Signal Connections in your MIO 16E manual for pin descriptions The signals from the SC 2040 screw terminal connectors are connected to the MIO 16E via J12 as shown in Figure 3 2 Observe that the PFI7 STARTSCAN signal returns from the MIO 16E as a level sensitive track and hold signal to the SC 2040 Notice also that AISENSE is disconnected O National Instruments Corporation 3 5 SC 2040 User Manual Signal Connections SC 2040 Input Signals SC 2040 Screw Terminals SC 2040 User Manual Track Hold Figure 3 2 SC 2040 Signal Routing 3 6 Chapter 3 Signals Sent to MIO 16 AIGND AISENSE ACHO ACH1 PFI2 STARTSCAN PFI7 DGND J11 and J12 Connectors on SC 2040 O National Instrum
47. on 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 National Instruments Products DAQ Hardware Revision e Interrupt Level of Hardware DMA Channels of Hardware e Base I O Address of Hardware e NI DAQ Version Other Products e Computer Make and Model e Microprocessor e Clock Frequency e Type of Video Board Installed e Operating System e Operating System Version e Operating System Mode e Programming Language Programming Language Version e Other Boards in System e Base I O Address of Other Boards DMA Channels of Other Boards e nterrupt Level of Other Boards Documentation Comment Form National Instruments encourages you to comment on the documentation supplied with our products This information helps us provide quality products to meet your needs Title SC 2040 User Manual Edition Date September 1994 Part Number 371191A 01 Please comment on the completeness clarity and organization of the manual If you find errors in the manual pl
48. on and operation The SC 2040 is an eight channel simultaneously sampling differential amplifier for the National Instruments MIO 16E Series DAQ boards The SC 2040 samples all eight channels at the same time preserving interchannel phase relationships for the MIO 16E Organization of This Manual The SC 2040 User Manual is organized as follows Chapter 1 Introduction describes the SC 2040 lists what you need to get started with your SC 2040 describes the optional software and optional equipment and explains how to unpack your SC 2040 Chapter 2 Configuration and Installation describes the configuration and installation of your SC 2040 The topics discussed are switch and jumper configuration connection of the SC 2040 to the MIO 16E and the power on sequence for your SC 2040 configuration Chapter 3 Signal Connections describes the signal connections to the SC 2040 board and cable wiring Chapter 4 Theory of Operation contains a functional overview of the SC 2040 board and explains the operation of each functional unit making up the SC 2040 Chapter 5 Calibration Procedures discusses the calibration procedures for the SC 2040 board Appendix A Specifications lists the specifications for the SC 2040 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 manua
49. over 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 NI DAQS and RTSI are trademarks of National Instruments Corporation Product names and company names listed are trademarks or trade names of their respective companies Warning Regarding Medical and Clinical Use of National Instruments Products National Instruments products are not designed with components and testing intended to ensure a level of reliability suitable for use in treatment and diagnosis of humans Applications of National Instruments products involving medical or clinical treatment can create a potential for accidental injury caused by product failure or by errors on the part of the user or application designer Any use or application of National Instruments products for or involving medical or clinical treatment must be performe
50. renced Signal Connection essere 3 7 Floating Signal Connection tibia ii ERR een ve MR ineo 3 8 Ground Referenced AC Coupled Signal Connection sss 3 9 Ground Offset AC Coupled Signal Connection esee 3 9 Floating AC Coupled Signal Connection eene 3 10 SC 2040 Block Diagrams tl iS 4 2 T H Amplifier Hold Settling Time and Track Acquisition Time 4 4 MIO 16E Controlled Trigg ering urs aee tii 4 5 External ITI Permg ad 4 6 Tables Power Supply Selection xo Qe opened ee ascent eth eidut berto baise 2 3 Shield Sel cHOI aco ood es lote ie cesa bei 2 4 DAQ Board Ground Isolation Selection essere 2 4 Channel Gain Selec a 2 5 Channel Input Mode z iade pae tesi ro ode ta 2 5 Gain Switches for Each Channel cocina 2 6 Switch Settings for Gain Selection eene enne 2 7 Input Mode Selection Jumpers rindo inclina 2 7 Pin Assignments for Connectors J11 and J12 eee 3 3 Input Connectors Signal Summary seen nennen 3 4 Output Connectors J11 and J12 Signal Summary esses 3 4 Calibration Component Identification eene 5 3 O National Instruments Corporation vii SC 2040 User Manual About This Manual This manual describes the electrical and mechanical aspects of the SC 2040 and contains information concerning its configurati
51. rt circuit but at a gain of 500 1 mV referred to the output is only 2 uV referred to the input Thermoelectric effects make it difficult to keep a short circuit from generating such voltages The best solution is to use short lengths of heavy copper wire and to keep the short away from heat sources 3 Program the DAQ board to take data in the differential input mode The SC 2040 should switch between track mode and hold mode with the DAQ board sampling occurring while the board is in hold mode National Instruments Corporation 5 3 SC 2040 User Manual Calibration Procedures Chapter 5 4 Setthe DAQ board to a high gain and measure its offset by shorting its input You must subtract this measured offset from all subsequent board measurements to ensure accuracy For the offset of the DAQ board not to affect the calibration you must subtract the offset from all board offset measurements Thus you must first measure the offset to an accuracy better than that to which the board is to be calibrated Furthermore setting the DAQ board to a high gain 100 for example makes it possible to resolve offset changes that would be indiscernible at lower gains Because the DAQ board offset will not be independent of gain you should set the gain first and then measure the offset To measure the offset disconnect the board from the DAQ board short circuit the board inputs to ground and take some data The measured value is the offset For a relia
52. table 3 4 input mode selection 2 7 installation power on sequence 2 8 steps for 2 8 National Instruments Corporation unpacking the SC 2040 1 4 instrumentation amplifiers 4 3 INT switch position table 2 3 J J11 and J12 connectors See connectors J11 and J12 jumpers and switches See configuration L LabVIEW and LabWindows application software 1 2 M manual See documentation MIO 16E DAQ board triggering 4 4 to 4 5 monitoring signal inputs 3 11 O operation of SC 2040 See theory of operation output connection 4 6 output connectors J11 and J12 signal summary table 3 4 to 3 5 P parts locator diagram 2 2 physical specifications A 3 pin assignments for SC 2040 I O connectors J11 and J12 table 3 3 power on sequence 2 8 power supply description 4 6 selecting procedure for 2 6 table 2 3 specifications A 3 O National Instruments Corporation Index R register level programming 1 4 S SC 2040 block diagram 4 2 features 1 1 T O connectors J11 and J12 illustration 3 2 optional equipment 1 4 required components 1 1 software programming choices LabVIEW and LabWindows application software 1 2 NI DAQ driver software 1 2 to 1 3 register level programming 1 4 unpacking 1 4 shield selection procedure for 2 4 table 2 4 SHLD OFF jumper position table 2 4 SHLD ON jumper position table 2 4 signal connections analog signal inputs 3 7 to 3 1 AC
53. tch to either power the SC 2040 from the MIO 16E board or to draw power from an external 5 V supply From the 5 V power an onboard DC to DC converter generates a 15 V source which is used to power the analog circuitry A red LED indicates that the board is receiving power SC 2040 User Manual 4 6 O National Instruments Corporation Chapter 5 Calibration Procedures This chapter discusses the calibration procedures for the SC 2040 board Note In many applications the SC 2040 factory hardware calibration is sufficient to meet accuracy requirements and no further calibration either hardware or software is needed Although hardware calibration is discussed in greater detail than software calibration software calibration is the preferred choice for the following reasons e The calibration adjustments on the SC 2040 are inaccessible under most normal operating circumstances e With software calibration the board is calibrated in the exact environment in which it will be operating Software calibration compensates for system introduced in addition to board introduced errors You can perform software calibration fairly frequently which helps reduce drift effects Because board introduced errors are minimal with the SC 2040 the use of software rather than hardware calibration does not significantly reduce dynamic range The main drawback of software calibration is reduced throughput due to the increased processing time Software
54. ware is included with LabVIEW The LabVIEW Data Acquisition VI Libraries are functionally equivalent to the NI DAQ software except that the SCXI functions are not included in the LabVIEW software for Sun LabWindows has two versions LabWindows for DOS is for use on PCs running DOS and LabWindows CVI is for use on PCs running Windows and for 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 DAQ hardware is included with the NI DAQ software kit The LabWindows Data Acquisition libraries are functionally equivalent to the NI DAQ software except that the SCXI functions are not included in the LabWindows CVI software for Sun Using LabVIEW or LabWindows software will greatly reduce the development time for your data acquisition and control application NI DAQ Driver Software The NI DAQ driver software is included at no charge with all National Instruments DAQ hardware NI DAQ is not packaged with SCXI or accessory products NI DAQ 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
55. xternal 5 V The SC 2040 fuses the input to 1 A of the 5 V supply Table 3 3 Output Connectors J11 and J12 Signal Summary J11 Pin J12 Pin Signal Name Description 50 pin 68 pin 1 2 4 6 8 23 24 26 27 AIGND Analog Input Ground These pins establish the 10 12 14 16 29 31 32 34 reference point for the SC 2040 outputs ACH lt 0 7 gt 18 56 58 50 61 They are also connected directly to the AIGND input 63 64 66 67 connector J5 for use with AC coupled signals 3 5 7 9 11 68 33 65 30 ACH lt 0 7 gt Analog Channels 0 through 7 These pins carry the 13 15 17 28 60 25 57 outputs of the SC 2040 eight channels to the DAQ board They are referenced to AIGND 24 33 4 7 9 12 13 Digital Ground These pins are the reference for the 15 18 35 36 5 V power source and for the digital signals used by 39 44 50 53 the SC 2040 TRIG PFI2 and TRACK HOLD PFI7 STARTSCAN 8 14 5 VDC Source When internal power is selected these pins provide DC power for the SC 2040 from the MIO 16E board The MIO 16E pins are fused to 1 A of 5 V supply TRIG PFI2 Trigger This pin which is connected directly to the TRIG input on screw terminal connector J10 is a trigger input to the MIO 16E PFI2 line A low to high transition on PFI2 alerts the MIO 16E to place the SC 2040 into hold mode and start acquiring data continues SC 2040 User Manual 3 4 O National Instruments Corporati
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