National Instruments SCXI-1121 User Manual

™

SCXI

SCXI-1121 User Manual

Four-Channel Isolated Universal Transducer Module for Signal Conditioning

SCXI-1121 User Manual

September 1999 Edition

Part Number 320426C-01

Worldwide Technical Support and Product Information

www.natinst.com

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For further support information, see the Technical Support Resources appendix. To comment on the documentation, send e-mail to techpubs@natinst.com.

Important Information

Warranty

The SCXI-1121 is warranted against defects in materials and workmanship f or 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. T his w arran ty i ncludes part s and l abo r.

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 warrant y.

National Instruments believes that the information in this document is accurate. The document has been carefully reviewed for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition. The reader should consult National Instruments if errors are suspected. In no even t shall Nati on al Inst rum ents be l iable fo r any dama ges aris in g o ut of or related to this document or the information contained in it.

XCEPT AS SPECIFIED HEREIN

WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER

ATIONAL 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

will apply regardless of the form of action, whether in contract or tort, including negligence. Any action against National Instruments must be brought within one year after the cause of action accrues. National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control. The warranty provided herein does not cover damages, defects, malfunctions, or service failures caused by owner’s failure to follow the National Instruments installation, operation, or maintenance instructions; owner’s modification of the product; owner’s abuse, misuse, or negligent acts; and power failure or surges, fire, flood, accident, actions of third part ies, o r other eve nts o ut side reasonab le co ntrol .

ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY

, N

Copyright

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Trademarks

LabVIEW™, natinst.com™, National Instruments™, NI-DAQ™, RTSI™, and SCXI™ are trademarks of National Instruments Corporation.

Product and company names mentioned herein are trademarks or trade names of their respective companies.

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT

. C

. This limitation of the liability of National Instruments

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

(1) NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANT S OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN.

(2) IN ANY APPLICATION, INCLUDING THE ABOVE, RELIABILITY OF OPERATION O F THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY, COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION, INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED “SYSTEM FAILURES”). AN Y A PPLICATION WHE RE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH) SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH , TH E U SER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS' TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS, THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBL E FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENT S PRODUCTS WHENEVE R NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR A PPLICATION, INCL UDING , WITHOUT LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

About This Manual

Conventions ...................................................................................................................xi

Related Documentation........................................... .......................................................xii

Chapter 1 Introduction

What Your Kit Should Contain .....................................................................................1-2

Optional Software.............................................................. ............................................1-2

Optional Equipment.......................................................................................................1-4

Custom Cables.................................................................................................1-5

Unpacking......................................................................................................................1-6

Chapter 2 Configuration and Installation

Module Configuration....................................................................................................2-1

Digital Signal Connections..............................................................................2-3

Jumper W44......................................................................................2-3

Jumper W38......................................................................................2-4

Jumper W32......................................................................................2-4

Using Jumpers W32 and W38 ..........................................................2-4

Analog Configuration......................................................................................2-6

Grounding, Shielding, and Reference Mode Selection.....................2-6

Input Channel Jumpers......................................................................2-8

Excitation Jumpers......................................... ...................................2-9

Hardware Installation.....................................................................................................2-14

Signal Connections .................................................... ....................................................2-15

Front Connector...............................................................................................2-16

Front Connector Signal Descriptions ..............................................................2-18

Analog Input Channels......................................................................2-20

Excitation Channels ........................................................ ..................2-22

Temperature Sensor Connection.......................................................2-22

Connector-and-Shell Assembly ........................................................2-22

SCXI-1320, SCXI-1328, and SCXI-1321 Terminal Blocks.............2-24

Rear Signal Connector.....................................................................................2-37

Rear Signal Connector Signal Descriptions ...................................................2-38

Analog Output Signal Connections................................................... 2-39

Digital I/O Signal Connections.........................................................2-40

Timing Requirements and Communication Protocol........................2-42

Communication Signals....................................................................2-42

Contents

Chapter 3 Theory of Operation

Functional Overview.....................................................................................................3-1

SCXIbus Connector ........................................................................................3-3

SCXIbus Connector Signal Descriptions........................................................3-4

Digital Interface............................................................. ................................................3-6

Digital Control Circuitry ...............................................................................................3-7

Analog and Timing Circuitry ........................................................................................3-8

Analog Input Channels....................................................................................3-8

Excitation Output Channels............................................................................3-11

Calibration.......................................................................................................3-11

Analog Output Circuitry .................................................................................3-15

Scanning Modes .............................................................. ..............................................3-17

Single-Module Parallel Scanning....................................................................3-17

Multiplexed Scanning.....................................................................................3-17

Calibration Equipment Requirements ..............................................3-11

Offset Null Adjust ............................................................................3-12

Excitation Adjust..............................................................................3-13

Single-Module Multiplexed Scanning..............................................3-18

Multiple-Module Multiplexed Scanning ..........................................3-19

Multiple-Chassis Scanning...............................................................3-20

Chapter 4 Register Descriptions

Register Description......................................................................................................4-1

SCXI-1121 Registers ......................................................................................4-1

Slot 0 Register Descriptions............................................................................4-5

Chapter 5 Programming

Programming Considerations........................................................................................5-1

Notation...........................................................................................................5-1

Initialization......................................................................................5-3

Single-Channel Measurements .......................................................................5-4

Direct Measurements........................................................................5-4

Indirect Measurements .....................................................................5-5

Scanning Measurements ...................................... ...........................................5-7

1. Data Acquisition Board Setup Programming............................... 5-7

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2. Module Programming ...................................................................5-10

3. Programming the Slot 0 Hardscan Circuitry.................................5-13

4. Acquisition Enable, Triggering, and Servicing.............................5-14

Scanning Examples................................... ... ..................................................................5-15

Example 1........................................................................................................5-15

Example 2........................................................................................................5-15

Example 3........................................................................................................5-16

Appendix A Specifications

Appendix B Rear Signal Connector

Appendix C SCXIbus Connector

Appendix D SCXI-1121 Front Connector

Contents

Appendix E SCXI-1121 Cabling

Appendix F Revision A and B Photo and Parts Locator Diagrams

Appendix G Technical Support Resources

Glossary

Index

Contents

Figures

Figure 2-1. SCXI-1121 General Parts Locator Diagram.........................................2-2

Figure 2-2. SCXI-1121 Detailed Parts Locator Diagram........................................2-3

Figure 2-3. SCXI-1121 Front Connector Pin Assignment ......................................2-18

Figure 2-4. Ground-Referenced Signal Connection with

High Common-Mode Voltage ..............................................................2-21

Figure 2-5. Floating Signal Connection Referenced to Chassis Ground for

Better Signal-to-Noise Ratio.................................................................2-21

Figure 2-6. Floating AC-Coupled Signal Connection.............................................2-22

Figure 2-7. AC-Coupled Signal Connection with High Common-Mode Voltage.. 2-22 Figure 2-8. Assembling and Mounting the SCXI-1330

Connector-and-Shell Assembly ............................................................2-25

Figure 2-9. Nulling Circuit ......................................................................................2-29

Figure 2-10. Shunt Circuit.........................................................................................2-30

Figure 2-11. SCXI-1320 Parts Locator Diagram.......................................................2-36

Figure 2-12. SCXI-1328 Parts Locator Diagram.......................................................2-37

Figure 2-13. SCXI-1321 Parts Locator Diagram.......................................................2-38

Figure 2-14. SCXI-1121 Rear Signal Connector Pin Assignment ............................ 2-39

Figure 2-15. SCANCLK Timing Requirements........................................................2-43

Figure 2-16. Slot-Select Timing Diagram.................................................................2-44

Figure 2-17. Serial Data Timing Diagram.................................................................2-45

Figure 2-18. Configuration Register Write Timing Diagram....................................2-46

Figure 2-19. SCXI-1121 Module ID Register Timing Diagram ...............................2-47

Figure 3-1. SCXI-1121 Block Diagram...................................................................3-1

Figure 3-2. SCXIbus Connector Pin Assignment....................................................3-3

Figure 3-3. Digital Interface Circuitry Block Diagram ........................................... 3-6

Figure 3-4. SCXI-1121 Digital Control...................................................................3-7

Figure 3-5. Analog Input Block Diagram................................................................3-9

Figure 3-6. Analog Output Circuitry.......................................................................3-15

Figure 3-7. Single-Module Parallel Scanning .........................................................3-17

Figure 3-8. Single-Module Multiplexed Scanning (Direct) ....................................3-18

Figure 3-9. Single-Module Multiplexed Scanning (Indirect)..................................3-19

Figure 3-10. Multiple-Module Multiplexed Scanning...............................................3-19

Figure 3-11. Multiple-Chassis Scanning ...................................................................3-20

Figure B-1. SCXI-1121 Rear Signal Connector Pin Assignment ............................ B-1

Figure C-1. SCXIbus Connector Pin Assignment....................................................C-2

Figure D-1. SCXI-1121 Front Connector Pin Assignment......................................D-2

Figure E-1. SCXI-1340 Installation .........................................................................E-4

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Tables

Contents

Figure E-2. SCXI-1180 Rear Connections...............................................................E-9

Figure E-3. SCXI-1180 Front Panel Installation......................................................E-10

Figure E-4. Cover Removal......................................................................................E-11

Figure F-1. Revision A and B SCXI-1121 Signal Conditioning Module................F-1

Figure F-2. Revision A and B SCXI-1121 General Parts Locator Diagram............F-2

Figure F-3. Revision A and B SCXI-1121 Detailed Parts Locator Diagram...........F-3

Table 2-1. Digital Signal Connections, Jumper Settings........................................2-6

Table 2-2. Jumper W33 Settings.............................................................................2-8

Table 2-3. Gain Jumper Allocation.........................................................................2-9

Table 2-4. Gain Jumper Positions...........................................................................2-9

Table 2-5. Filter Jumper Allocation........................................................................2-10

Table 2-6. Voltage and Current Mode Excitation Jumper Setup............................2-11

Table 2-7. Maximum Load per Excitation Channel...............................................2-12

Table 2-8. Excitation Level Jumper Selection........................................................2-12

Table 2-9. Completion Network Jumpers............................................................... 2-14

Table 2-10. Trimmer Potentiometer and Corresponding Channel ...........................2-27

Table 2-11. Nulling Resistors and Corresponding Channel.....................................2-27

Table 2-12. Jumper Settings of the Nulling Circuits................................................2-29

Table 2-13. Jumper Settings on the SCXI-1320 Terminal Block.............................2-33

Table 2-14. Jumper Settings on the SCXI-1328 Terminal Block.............................2-34

Table 2-15. Jumper Settings on the SCXI-1321 Terminal Block.............................2-34

Table 2-16. SCXIbus to SCXI-1121 Rear Signal Connector to

Data Acquisition Board Pin Equivalences ............................................2-42

Table 3-1. SCXIbus Equivalents for the Rear Signal Connector ...........................3-5

Table 3-2. Calibration Potentiometer Reference Designators................................3-14

Table 5-1. SCXI-1121 Rear Signal Connector Pin Equivalences ..........................5-2

Table E-1. SCXI-1121 and MIO-16 Pinout Equivalences......................................E-2

Table E-2. SCXI-1341 and SCXI-1344 Pin Translations.......................................E-5

Table E-3. SCXI-1342 Pin Translations .................................................................E-7

Table E-4. SCXI-1343 Pin Connections.................................................................E-14

About This Manual

This manual describes the electrical and mechanical aspects of the SCXI-1121 and contains information concerning its operation and programming. The SCXI-1121 is a member of the National Instruments Signal Conditioning eXtensions for Instrumentation (SCXI) Series for the National Instruments data acquisition plug-in boards. This board is designed for signal conditioning of strain gauges, RTDs, thermistors, thermocouples, volt and millivolt sources, and 4 to 20 mA sources or 0 to 20 mA process-current sources where high common-mode voltages exist. The SCXI-1121 operates as four isolated input channels and four isolated excitation channels. Each channel is isolated and independently configurable via jumpers.

This manual describes the installation, basic programming considerations, and theory of operation for the SCXI-1121.

Conventions

The following conventions appear in this manual:

<> Angle brackets that contain numbers separated by an ellipsis represent a

range of values associated with a bit or signal name—for example, DBIO<3..0>.

This icon denotes a note, which alerts you to important information. This icon denotes a caution, which advises you of precautions to take to

avoid injury, data loss, or a system crash. This icon denotes a warning, which advises you of precautions to take to

avoid being electrically shocked.

bold Bold text denotes items that you must select or click on in the software,

such as menu items and dialog box options. Bold text also denotes parameter names.

italic Italic text denotes variables, emphasis, a cross reference, or an introduction

to a key concept. This font also denotes text that is a placeholder for a word or value that you must supply.

About This Manual

monospace Text in this font denotes text or characters that you should enter from the

keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions, operations, variables, filenames and extensions, and code excerpts.

monospace italic

Italic text in this font denotes text that is a placeholder for a word or value that you must supply.

What Your Kit Should Contain

The contents of the SCXI-1121 kit (part number 776572-21) are listed as follows:

Kit Component Part Number

SCXI-1121 module 181700-01 SCXI-1121 User Manual 320426-01

If your kit is missing any of the components, contact Nati onal Instruments .

Optional Software

This manual contains complete instructions for directly programming the SCXI-1121. You can order separate software packages for controlling the SCXI-1121 from National Instruments.

When you combine the PC, AT, and MC data acquisition boards with the SCXI-1121, you can use LabVIEW for Windows or LabW indows for DOS. LabVIEW and LabWindows are inno vativ e program development software packages for data acquisition and control applications. LabVIEW uses graphical programming, whereas LabWindows enhances Microsoft C and QuickBASIC. Both packages include extensive libraries for data acquisition, instrument control, data analysis, and graphical data presentation.

Your National Instruments data acquisition board is shipped with the NI-DA Q software. NI-DA Q has a 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, SCXI, RTSI, and self-calibration. NI-DAQ maintains a consistent software interface among its different versions so you can switch between platforms with minimal modifications to your code.

You can also use the SCXI-1121, together with the PC, AT, and MC data acquisition boards, with NI-DAQ software for DOS/Windows/ LabWindows/CVI. NI-DAQ software for DOS/Windows/ LabWindows/CVI comes with language interfaces for Professional BASIC, T urbo Pascal, T urbo C, T urbo C++, Borland C++, and Microsoft C

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Chapter 1 Introduction

for DOS and Visual Basic, Turbo Pascal, Microsoft C with SDK, and Borland C++ for Windows. NI-DAQ software for DOS/Windows/LabWindows is on high-density 5.25 in. and 3.5 in. diskettes.

You can use the SCXI-1121, together with the Lab-LC or NB Series data acquisition boards, with LabVIEW for Macintosh, a software system that features interactive graphics, a state-of-the-art user interface, and a powerful graphical programming language. The LabVIEW Data Acquisition VI Library, a series of VIs for using LabVIEW with National Instruments boards, is included with LabVIEW. The LabVIEW Data Acquisition VI Library is functionally equivalent to the NI-DAQ software for Macintosh.

You can also use the SCXI-1121, combined with the NB Series data acquisition boards, with NI-DAQ software for Macintosh. NI-DAQ software for Macintosh, which is shipped with all National Instruments Macintosh data acquisition boards, 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.

Chapter 1 Introduction

Optional Equipment

NB6 cable

0.5 m 181305-01

1.0 m 181305-10 SCXI-1320 front terminal block 776573-20 SCXI-1321 offset-null and shunt-calibration terminal block 776573-21 SCXI-1328 high-accuracy isothermal terminal block 776573-28 SCXI-1330 32-pin connector-and-shell assembly 776573-30 SCXI-1340 cable assembly 776574-40 SCXI-1341 Lab-NB/Lab-PC/Lab-PC+ cable assembly 776574-41 SCXI-1342 PC-LPM-16 cable assembly 776574-42 SCXI-1343 rear screw terminal adapter 776574-43 SCXI-1344 Lab-LC cable assembly 776574-44 SCXI-1346 shielded multichassis cable adapter 776574-46

Equipment Part Number

SCXI-1347 SCXI shielded cable assembly

with 1 m cable 776574-471 with 2 m cable 776574-472 with 5 m cable 776574-475 with 10 m cable 776574-470

SCXI-1349 SCXI shielded cable assembly

with 1 m cable 776574-491 with 2 m cable 776574-492 with 5 m cable 776574-495

with 10 m cable 776574-490 SCXI-1350 multichassis adapter 776575-50 SCXI process-current resistor kit 776582-01 Standard ribbon cable

0.5 m 180524-05

1.0 m 180524-10

SCXI-1121 User Manual 1-4 www.natinst.com

Custom Cables

Chapter 1 Introduction

Refer to the Signal Connections section in Chapter 2, Configuration and

Installation, and to Appendix E, SCXI-1121 Cabling, for additional

information on cabling, connectors, and adapters.

The SCXI-1121 rear signal connector is a 50-pin male ribbon-cable header. The manufacturer part number used by National Instruments for this header is as follows:

• AMP Inc. (part number 1-103310-0) The mating connector for the SCXI-1121 rear signal connector is a

50-position polarized ribbon-socket connector with strain relief. National Instruments uses a polarized or keyed connector to prevent inadvertent upside-down connection to the SCXI-1121. Recommended manufacturer part numbers for this mating connector are as follows:

• Electronic Products Division/3M (part number 3425-7650)

• T&B/Ansley Corporation (part number 609-5041CE) Standard 50-conductor, 28 AWG, stranded ribbon cables that can be used

with these connectors are as follows:

• Electronic Products Division/3M (part number 3365/50)

• T&B/Ansle y Corporation (part number 171-50) The SCXI-1121 front connector is a 32-pin DIN C male connector with

column A and column C even pins only. The manufacturer part number used by National Instruments for this connector is as follows:

• Panduit Corporation (part number 100-932-023) The mating connector for the SCXI-1121 front connector is a 32-pin DIN C

female connector. National Instruments uses a polarized connector to prevent inadvertent upside-down connection to the SCXI-1121. Recommended manufacturer part numbers for this mating connector are as follows:

• Panduit Corporation (part number 100-932-434 straight-solder eyelet pins)

• Panduit Corporation (part number 100-932-633; right-angle pins)

National Instruments selected these connectors to meet UL 1950 and UL 1244 for 1,500 V

isolation.

rms

Chapter 1 Introduction

Unpacking

Your SCXI-1121 module is shipped in an antistatic package to prevent electrostatic damage to the module. Several components on the module can be damaged by electrostatic discharge. To avoid such damage in handling the module, take the following precautions.

• Touch the antistatic package to a metal part of your SCXI chassis before removing the module from the package.

• Remo ve the module from the package and inspect the module for loose components or any other sign of damage. Notify National Instruments if the module appears damaged in any way. Do not install a damaged module into your SCXI chassis.

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Configuration and Installation

This chapter describes the SCXI-1121 jumper configurations, installation of the SCXI-1121 into the SCXI chassis, signal connections to the SCXI-1121, and cable wiring.

Module Configuration

The SCXI-1121 contains 49 jumpers that are shown in the parts locator diagrams in Figures 2-1 and 2-2.

Figure 2-1.

SCXI-1121 General Parts Locator Diagram

Chapter 2 Configuration and Installation

Figure 2-2. SCXI-1121 Detailed Parts Locator Diagram

The jumpers are used as follows:

• Fixed jumpers – On Revision A and B modules, jumper W32 is unused and should

not be connected. – Jumper W45 is reserved and should not be reconfigured. – On Revision A and B modules, jumper W44 carries the

SLOT0SEL* signal from the rear signal connector, after

buffering, to the SCXIbus INTR* line and should be left in the

factory-set position (position 1). On Revision C or later modules,

jumper W44 does not exist.

• User-configurable jumpers – Jumper W38 carries the SCXIbus MISO line, after buffering, to

the SERDATOUT signal on the rear signal connector.

– On Revision C or later modules, jumper W32 connects a pullup

resistor to the SERDATOUT signal on the rear signal connector.

– Jumper W33 configures the guard, the analog output ground, and

enables the Pseudodifferential Reference mode.

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Chapter 2 Configuration and Installation

– Jumpers W3, W19, W29, and W41 configure the first-stage gain

of input channels 0 through 3, respectively.

– Jumpers W4, W20, W30, and W42 configure the second-stage

gain of input channels 0 through 3, resp ectively.

– Jumpers W5, W21, W31, and W43 configure the first-stage

filtering of input channels 0 through 3, respectively.

– Jumpers W6 and W7, W8 and W9, W10 and W11, and W12 and

W13 configure the second-stage filtering of input channels 0 through 3, respectively.

– Jumpers W14 and W15, W22 and W23, W34 and W35, and W46

and W47 configure the voltage or current mode of operation for excitation channels 0 through 3, respectively.

– Jumpers W16 and W26, W24 and W25, W36 and W37, and W48

and W49 configure the level of excitation for excitation channels 0 through 3, respectively.

– Jumpers W1 and W2, W17 and W18, W27 and W28, and W39

and W40 configure the half-bridge completion network for channels 0 through 3, respectively.

Further configuration of the board is software controlled and will be discussed later in this chapter.

Digital Signal Connections

The SCXI-1121 has three jumpers dedicated for communication between the data acquisition board and the SCXIbus. These jumpers are W32, W38, and W44.

Jumper W44

Position 1 on Revision A and B modules connects, after buffering, SLOT0SEL* to the SCXIbus INTR* line. This is the factory-default setting and should not be changed. In this setting, the data acquisition board controls the SCXIbus INTR* line. See the Timing Requirements and

Communication Protocol section later in this chapter, and Chapter 5, Programming, for information on the use of the INTR* line. See

Appendix E, SCXI-1121 Cabling, for the pin equivalences of the SCXI-1121 rear signal connector and the data acquisition board I/O connector.

Position 3 is reserved and should not be used. This position is not explicitly marked on the module.

Chapter 2 Configuration and Installation

On Revision C or later modules, jumper W44 does not exist. SLOT0SEL* is always buffered to the INTR* line.

Jumper W38

Position 1 connects, after buffering, the SCXIbus MISO line to the SERDATOUT pin of the rear signal connector. In this setting, along with the proper setting of W32, the data acquisition board can read the Module ID Register of the SCXI-1121. See the Timing Requirements and

Communication Protocol section later in this chapter, and Chapter 4, Register Descriptions, for information on reading the Module ID Register.

See Appendix E, SCXI-1121 Cabling, for the pin equivalences of the SCXI-1121 rear signal connector and the data acquisition board I/O connector. This is the factory-default setting.

Position 3 disconnects SERDATOUT from the SCXIbus MISO line.

Jumper W32

On Revision A and B modules, jumper W32 should not be connected. On Revision C or later modules, Position 1 connects a 2.2 kΩ pullup resistor to the SERDATOUT line (factory-default setting), and Position 3 does not connect the pullup resistor to the SERDATOUT line.

Using Jumpers W32 and W38

Set jumpers W32 and W38 as follows: If the SCXI-1121 is not cabled to a data acquisition board, the positions of

these jumpers do not matter, so leav e them in their factory default positions (both in position 1).

If the SCXI-1121 is cabled to a data acquisition board, and the SCXI chassis that the SCXI-1121 is in, is the only SCXI chassis cabled to that data acquisition board, leave the jumpers in their factory default positions (both in position 1).

If the SCXI-1121 is cabled to a data acquisition board, and there are multiple SCXI chassis cabled to that data acquisition board with shielded cables (you are using SCXI-1346 shielded cable multi-chassis adapters), leave the jumpers in their factory default positions (both in position 1).

If the SCXI-1121 is cabled to a data acquisition board, and there are multiple SCXI chassis cabled to that data acquisition board with ribbon cables (you are using SCXI-1350 multi-chassis adapters), leave jumper

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Chapter 2 Configuration and Installation

W38 in its factory default position (position 1). On all but one of the SCXI-1121s that are cabled to the data acquisition board, move jumper W32 to position 3. It does not matter which of the SCXI-1121 modules that are cabled to the data acquisition board has jumper W32 set to position 1. If you have different types of modules cabled to the data acquisition board, those different modules will have jumpers similar to W38 and W32 of the SCXI-1121. Set those jumpers on the different modules using the same method described here for the SCXI-1121.

On Revision A and B SCXI-1121s, jumper W32 is not used. Y ou set jumper W38 as explained in the cases above, except in the case of a multiple chassis ribbon cable system. In a multichassis ribbon cable system with Revision A and B SCXI-1121s cabled to the data acquisition board, you can access the MISO line in only one chassis. Pick one of the chassis and set jumper W38 to position 1 on the SCXI-1121 in that chassis that is cabled to the data acquisition board. On the SCXI-1121s that are in the other chassis and cabled to the data acquisition board, set jumper W38 to position 3. Notice that you will only be able to access digital information from the chassis that has the SCXI-1121 with jumper W38 set to position 1.

Table 2-1. Digital Signal Connections, Jumper Settings

Jumper Description Configuration

W38 Factory setting;

connects MISO to SERDATOUT

•

W38 Parking position

•

W45 Factory setting

•

Chapter 2 Configuration and Installation

Analog Configuration

The SCXI-1121 has 45 analog configuration jumpers.

Table 2-1.

Jumper Description Configuration

W44 Factory setting

W32 Fatory-default setting;

W32 Parking position (not

Digital Signal Connections, Jumper Settings (Continued)

(Revision A and B modules only)

connects pullup to SERDATOUT (Revision C and later)

connected on Revision A or B modules)

•

Before starting, notice that the jumper configurations for each input channel and each excitation channel are similar only the jumper numbers differ . Therefore, when you learn ho w to set up one channel pair (input and excitation), you can set up the other channel pairs as well.

Grounding, Shielding, and Reference Mode Selection

Jumper W33

Position AB-R0 connects the analog reference to the analog output ground (pins 1 and 2 on the rear signal connector). Select this configuration if you are using an RSE data acquisition board. It is not recommended to use a differential input data acquisition board when jumper W33 is in the AB-R0 position.

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Chapter 2 Configuration and Installation

•••••

•

R2 R 1 R 0

•••••

•

R2 R 1 R 0

•••••

•

R2 R 1 R 0

•••••

•

R2 R 1 R 0

Position AB-R1 connects the analog reference to the SCXIbus guard. Position A-R0R1 is the parking position and the factory setting. Position AB-R2 enables the Pseudodifferential Reference mode and

connects the analog reference to the OUTREF pin on the rear signal connector. Select this mode when the SCXI-1121 has to operate with data acquisition boards that have a nonreferenced single-ended (NRSE) input. It is not recommended to use differential-input data acquisition boards when jumper W33 is in the AB-R2 position.

Table 2-2. Jumper W33 Settings

Jumper Description Configuration

W33 Factory setting in

parking position

W33 Connects the

analog reference to AOGND (pins 1 and 2 of the rear signal connector)

W33 Connects SCXIbus

guard to the analog reference

W33 Enables the

Pseudodifferential Reference mode (pin 19 of the rear signal connector is connected to the analog reference)

Chapter 2 Configuration and Installation

Input Channel Jumpers

Gain Jumpers

Each input channel has two gain stages. The first gain stage provides gains of 1, 10, 50, and 100 and the second stage provides gains of 1, 2, 5, 10, and

20. Tables 2-3 and 2-4 show how to set up the gain for each channel.

Table 2-3.

Input Channel

Number

Gain Jumper Allocation

First Gain

Jumper

Second Gain

Jumper

0 W3 W4 1 W19 W20 2 W29 W30 3 W41 W42

The board is shipped to you with the first-stage gain set to 100 (position A) and a second-stage gain set to 10 (position D). To change the gain of your module, move the appropriate jumper on your module to the position indicated in T able 2-4. Refer to Figure 2-2 for the jumper locations on your module.

T o determine the o verall g ain of a giv en channel use the follo wing formula:

Overall gain = First-stage gain × second-stage gain

Table 2-4.

Gain Jumper Positions

Gain Setting Jumper Position

First-stage 1

10 50

100

A (factory setting)

Second-stage 1

2 5

D (factory setting)

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D C B

A B C

Chapter 2 Configuration and Installation

Filter Jumpers

Two-stage filtering is also available on your SCXI-1121 module. The first stage is located in the isolated section of the input channel, whereas the second stage is located in the nonisolated section of the input channel. This permits a higher signal-to-noise ratio by eliminating the noise generated by the isolation amplifier. Furthermore, two filter bandwidths are available—10 kHz and 4 Hz.

Table 2-5.

First Filter Jumper Second Filter Jumper

Input Channel

Number

0 W5-A W5-B W6 W7 1 W21-A W21-B W8 W9 2 W31-A W31-B W10 W11 3 W43-A W43-B W12 W13

4 Hz

(Factory Setting)

Your SCXI-1121 is shipped in the 4 Hz configuration. Always make sure to set both stages to the same bandwidth. This will ensure that the required bandwidth is achieved.

Filter Jumper Allocation

10 kHz

4 Hz

(Factory Setting)

Excitation Jumpers

Current and Voltage Excitation Jumpers

You can configure each excitation channel of your SCXI-1121 to either a Voltage or Current excitation mode. Each channel has two jumpers for this purpose. Set both jumpers in the same mode for correct operation of the excitation channel. Refer to Table 2-6 for setting up your module in the mode you want. Your SCXI-1121 is shipped to you in the Voltage mode.

10kHz

Chapter 2 Configuration and Installation

•

W14

1 2 3

•

W15

1 2 3

•

W22

1 2 3

•

W23

1 2 3

•

W34

1 2 3

•

W35

1 2 3

•

W46

1 2 3

•

W47

1 2 3

Table 2-6.

Excitation

Channel

Jumpers

0 W14 and W15

1 W22 and W23

2 W34 and W35

3 W46 and W47

Voltage and Current Mode Excitation Jumper Setup

Voltage Mode

(Factory Setting)

W14

•

1 2 3

W22

•

1 2 3

W34

•

1 2 3

W46

•

1 2 3

•

1 2 3

•

1 2 3

•

W15

•

W23

•

W35

•

W47

•

Current Mode

1 2 3

Excitation Level

Each excitation channel of your SCXI-1121 has two different current or voltage levels. You can set a given channel to one of the following level modes:

• In the Current mode 0.150 or 0.450 mA

• In the Voltage mode 3.333 or 10 V

It is important to notice that you should select the level of excitation according to the load you are using. Table 2-7 lists the maximum load that can be driven per channel at each level of excitation for both volt and current excitation.

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Chapter 2 Configuration and Installation

•

W16

1 2 3

•

W26

1 2 3

•

W24

1 2 3

•

W25

1 2 3

•

W36

1 2 3

•

W37

1 2 3

•

W48

1 2 3

•

W49

1 2 3

Table 2-7. Maximum Load per Excitation Channel

Excitation Level Maximum Load

3.333 V 28 mA 10 V 14 mA

0.150 mA 10 kΩ

0.450 mA 10 kΩ

After selecting the excitation mode of operation desired—Voltage or Current—as described in the previous section, use Table 2-8 to set your SCXI-1121 for the level of operation. Your SCXI-1121 is shipped with the Voltage mode set to 3.333 V.

Table 2-8. Excitation Level Jumper Selection

Excitation

Channel

0 W16 and W26

1 W24 and W25

2 W36 and W37

3 W48 and W49

Jumpers

3.333 V or 0.150 mA (Factory Setting)

W16

•

1 2 3

W24

•

1 2 3

W36

•

1 2 3

W48

•

2 3

W25

•

1 2 3

W37

•

1 2 3

W49

•

W26

•

10 V or 0.450 mA

•

1 2 3

Chapter 2 Configuration and Installation

A B

W18

W17

1 2 3

•••

•

Using the Internal Half-Bridge Completion

Your SCXI-1121 includes half-bridge completion for half-bridge and quarter-bridge setups. The completion network consists of two

4.5 kΩ ± 0.05% ratio tolerance resistors with a temperature coefficient of 5 ppm/°C. These resistors are connected in series. To enable the network, you must set two jumpers for each input/excitation channel pair.

When the completion network is enabled, you cannot access the negative input of the amplifier, which preserves the overvoltage protection of the channel. Table 2-9 shows how to enable and disable the completion network.

Note

When using the half-bridge completion network with a quarter-bridge setup, you must use an extra resistor to complete the bridge. Place this resistor on the terminal block between the positive input channel and the negative excitation output.

Table 2-9.

Completion Network Jumpers

Channel Jumpers Enable Completion

0 W1 and W2

•••

•

A B

•

1 2 3

1 W17 and W18

•••

W18

•

A B

•

W17

1 2 3

Disable Network

(Factory Setting)

•••

•

A B

•

1 2 3

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Table 2-9. Completion Network Jumpers (Continued)

A B

W28

W27

1 2 3

•••

•

A B

W40

W39

1 2 3

•••

•

Channel Jumpers Enable Completion

Chapter 2 Configuration and Installation

Disable Network (Factory Setting)

2 W27 and W28

3 W39 and W40

•••

•

A B

•

1 2 3

•••

•

A B

•

1 2 3

W28

•

W40

•

W27

W39

Chapter 2 Configuration and Installation

Hardware Installation

You can install the SCXI-1121 in any available SCXI chassis. After you have made any necessary changes and have verified and recorded the jumper settings on the form in AppendixG, Technical Support Resources, you are ready to install the SCXI-1121. The following are general installation instructions consult the user manual or technical reference manual of your SCXI chassis for specific instructions and warnings.

1. Turn off the computer that contains the data acquisition board or disconnect it from your SCXI chassis.

2. Turn off the SCXI chassis. Do not insert the SCXI-1121 into a chassis that is turned on.

3. Insert the SCXI-1121 into the board guides. Gently guide the module into the back of the slot until the connectors make good contact. If a cable assembly has already been installed in the rear of the chassis, the module and cable assembly must be firmly engaged; however, do not force the module into place.

4. Screw the front mounting panel of the SCXI-1121 to the top and bottom threaded strips of your SCXI chassis.

5. If this module is to be connected to an MIO-16 data acquisition board, attach the connector at the metal end of the SCXI-1340 cable assembly to the rear signal connector on the SCXI-1121 module. Screw the rear panel to the rear threaded strip. Attach the loose end of the cable to the MIO-16 board.

Note

For installation procedures with other SCXI accessories and data acquisition boards,

consult Appendix E, SCXI-1121 Cabling.

6. Check the installation.

7. Turn on the SCXI chassis.

8. Turn on the computer or reconnect it to your chassis.

The SCXI-1121 module is installed and ready for operation.

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National Instruments SCXI-1121 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

SCXI-1121 User Manual

Worldwide Technical Support and Product Information

National Instruments Corporate Headquarters

Worldwide Offices

Important Information

Warranty

Copyright

Trademarks

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

Contents

Figures

Tables

About This Manual

Conventions

Related Documentation

What Your Kit Should Contain

Optional Software

Optional Equipment

Custom Cables

Unpacking

Module Configuration

Figure 2-2. SCXI-1121 Detailed Parts Locator Diagram

Digital Signal Connections

Jumper W44

Jumper W38

Jumper W32

Using Jumpers W32 and W38

Table 2-1. Digital Signal Connections, Jumper Settings

Analog Configuration

Grounding, Shielding, and Reference Mode Selection

Table 2-2. Jumper W33 Settings

Input Channel Jumpers

Excitation Jumpers

Table 2-7. Maximum Load per Excitation Channel

Table 2-8. Excitation Level Jumper Selection

Hardware Installation