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.
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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.
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.
Contents About This Manual................................................................................................................ix Organization of This Manual ............................................................................................ix Conventions Used in This Manual....................................................................................x The National Instruments Documentation Set..................................................................
Contents Chapter 4 Theory of Operation .......................................................................................................... 4-1 Functional Overview......................................................................................................4-1 Analog Circuitry ............................................................................................................4-3 Input Protection...........................................................................................
Contents Figures Figure 1-1. The Relationship between the Programming Environment, NI-DAQ, and Your Hardware............................................................................. 1-3 Figure 2-1. SC-2040 Parts Locator Diagram..........................................................................2-2 Figure Figure Figure Figure Figure Figure Figure 3-1. 3-2. 3-3. 3-4. 3-5. 3-6. 3-7. SC-2040 I/O Connectors J11 and J12..................................................................
About This Manual This manual describes the electrical and mechanical aspects of the SC-2040 and contains information concerning its configuration 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.
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.
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 contact us, this manual contains comment and configuration forms for you to complete.
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.
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 NI-DAQ software for Macintosh.
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.
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: • CB-50 I/O connector (50-screw terminals) with 0.5 or 1.
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 poweron 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.
Configuration and Installation Chapter 2 Figure 2-1.
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.
Configuration and Installation Chapter 2 Table 2-2. Shield Selection Jumper Description SHLD OFF position—Place the jumper in this position to keep the SC-2040 analog ground isolated from the metal standoffs in the corners of the board (factory setting). W1 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. Configuration W1 SHLD OFF SHLD ON W1 SHLD OFF SHLD ON Table 2-3.
Chapter 2 Configuration and Installation Table 2-4. Channel Gain Selection Switch Description Configuration Unity gain position—For unity gain (gain = 1), open all the switches by pushing down the OFF end of the switches. (factory setting) U2 U6 U9 U14 U17 U21 U24 U28 A B C D 1 2 3 4 OFF 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.
Configuration and Installation Chapter 2 Supplementary Configuration Information Power Supply Selection Set switch SW1 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.
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.
Configuration and Installation 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.
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.
Signal Connections Chapter 3 1 2 3 4 5 6 7 8 9 10 11 12 13 34 33 68 32 66 31 65 30 29 64 63 28 62 61 14 27 26 15 16 25 24 17 18 19 20 21 22 23 24 25 26 27 29 67 60 59 58 23 22 21 20 19 57 56 18 52 17 51 28 16 15 50 30 14 31 32 13 48 47 33 34 35 36 37 38 39 40 41 42 43 44 4 39 38 45 46 3 2 37 36 47 48 1 35 49 50 12 11 10 9 8 55 54 53 49 46 45 44 43 42 41 40 7 6 5 B. I/O Connector J12 A. Breakout Connector J11 Figure 3-1.
Chapter 3 Signal Connections Table 3-1.
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, J6, J7, J8, J9 CH+<0..7> Positive Inputs—These inputs are the positive signal inputs for channels 0 through 7. J1, J2, J3, J4, J6, J7, J8, J9 CH-<0..7> Negative Inputs—These inputs are the negative signal inputs for channels 0 through 7.
Chapter 3 Signal Connections Table 3-3. Output Connectors (J11 and J12) Signal Summary (Continued) J11 Pin (50-pin) J12 Pin (68-pin) Signal Name Description 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.
Signal Connections J5 Chapter 3 SC-2040 Input Signals Signals Sent to MIO-16 AIGND AIGND AISENSE CH0+ J1 T/H ACH0 T/H ACH1 . . . . . . . . ACH7 CH0- CH1+ J2 CH1. . . . . . CH7 J9 T/H CH7 PFI2/ STARTSCAN TRIG J10 DGND PFI7 Track*/Hold DGND J11 and J12 Connectors on SC-2040 SC-2040 Screw Terminals Figure 3-2.
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.
Signal Connections Chapter 3 Figure 3-4 illustrates how to connect a floating signal. CH+ IN+ Vin CH- INA B C SC-2040 100 kΩ A 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.
Chapter 3 Signal Connections Figures 3-5 through 3-7 illustrate how to connect AC-coupled signals. CH+ IN+ Vin CH- INA B C 100 kΩ SC-2040 A Figure 3-5. Ground-Referenced AC-Coupled Signal Connection CH+ IN+ Vin CHINA B C 100 kΩ SC-2040 Analog GND A A Figure 3-6.
Signal Connections Chapter 3 CH+ IN+ Vin CH- INA B C SC-2040 100 kΩ A 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.
Chapter 3 Signal Connections where V+in is the signal at the positive input (IN0+ through IN7+), and V-i n is the signal at the corresponding negative input (IN0- through IN7-). Both V+in and V-i n 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.
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-andhold amplifier. The analog inputs are overvoltage protected.
Theory of Operation Chapter 4 68-Pin I/O Connector • • • • • • External +5 V Power Converter (External Trigger) • CH7- CH7+ CH0- CH0+ Gains Input Protection External Track/Hold Trigger • • A • A • + Inst. Amp - T/H + Inst. Amp Input Protection -15 V • +15 V • T/H • Gains (Track/Hold Signal) +5 V Power-On LED PFI2 ACH0 ACH7 PFI7 50-Pin Breakout Connector Figure 4-1.
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.
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.
SC-2040 Channel Output ........ hold ........... ...... ...... hold track ...... PFI7 (track*/hold) ...... Differential Channel Input ...... Theory of Operation ......... Chapter 4 t t DAQ Conversion DAQ 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.
Chapter 4 track hold t track ...... SC-2040 Channel Output ...... ........ hold ..... PFI7 (track*/hold) .... .... ........ ..... .... PFI2 (external trigger) ....... Differential Channel Input .... .......... Theory of Operation t DAQ Conversion (DAQ board is scanning) DAQ Conversion 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.
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.
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 source.
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 12 = 4.88 mV. Calibration to under 2 mV would thus be sufficient for most applications. The SC-2040 is factory calibrated to have total offset referred to output of less than 2 mV at low gains.
Calibration Procedures Chapter 5 4. Set the 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.
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 Input signal ranges Board Gain (Hardware Selectable) ±10 V ±1 V ±100 mV ±50 mV ±33.3 mV ±20 mV ±16.67 mV ±14.29 mV ±12.
Specifications Appendix A Amplifier Characteristics Input impedance Normal powered on Input bias current Input offset current 100 GΩ in parallel with 20 pF ±100 pA, ±10 mA max ±10 pA CMRR Output range Gain dB (min and typ) Gain = 1 Gain = 10 Gain ≥ 100 70 dB min, 90 dB typ 87 dB min, 104 dB typ 100 dB min, 110 dB typ ±10 V Dynamic Characteristics Bandwidth System noise Noise spectral density Input noise (gain = 1) Output noise Slew rate SC-2040 User Manual Gain -3 dB Bandwidth 1 10 100 200
Appendix A Specifications S/H Characteristics Measurement 0.012% 0.003% 0.0015% 0.
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.
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.
SC-2040 Hardware and Software Configuration Form Record the settings and revisions of your hardware and software on the line to the right of each item. Complete a new copy of this form each time you revise your software or hardware configuration, and use this form as a reference for your current configuration. Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently.
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, please record the page numbers and describe the errors. Thank you for your help.
Glossary ___________________________________________________ ˚ Ω A ACH# A/D Arms AWG C CH#+ CH#CMOS cps D/A DAQ dB DC DIN DIP FIFO hex Hz in.
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 track-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 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 (i
Index 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 procedure for, 2-6 to 2-7 switch settings (table), 2-7 table, 2-5 channel input mode (table), 2-5 CH+(0..
Index R unpacking the SC-2040, 1-4 instrumentation amplifiers, 4-3 INT switch position (table), 2-3 register-level programming, 1-4 J S J11 and J12 connectors. See connectors J11 and J12. jumpers and switches. See configuration.
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 t
