NI SCXI-1127 User manual

SCXI™
SCXI-1127 User Manual
32-Channel High-Voltage Multiplexer/Matrix Module
SCXI-1127 User Manual
January 1999 Edition
Part Number 322149A-01

Internet Support
E-mail: [e-mail]
FTP Site: ftp.natinst.com
Web Address: http://www.natinst.com
Bulletin Board Support
BBS United States: 512 794 5422
BBS United Kingdom: 01635 551422
BBS France: 01 48 65 15 59
Fax-on-Demand Support
512 418 1111
Telephone Support (USA)
Tel: [phone]
Fax: [phone]
International Offices
Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20, Brazil 011 288 3336,
Canada (Ontario) 905 785 0085, Canada (Québec) 514 694 8521, Denmark 45 76 26 00, Finland 09 725 725 11,
France 01 48 14 24 24, Germany 089 741 31 30, Hong Kong 2645 3186, Israel 03 6120092, Italy 02 413091,
Japan 03 5472 2970, Korea 02 596 7456, Mexico 5 520 2635, Netherlands 0348 433466, Norway 32 84 84 00,
Singapore 2265886,Spain 91 640 0085,Sweden 08 730 49 70,Switzerland 056 200 51 51,Taiwan 02 377 1200,
United Kingdom 01635 523545
National Instruments Corporate Headquarters
6504 Bridge Point Parkway Austin, Texas 78730-5039 USA Tel: [phone]
©Copyright 1999 National Instruments Corporation. All rights reserved.

Important Information
Warranty
The SCXI-1127 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.
The media on which you receive National Instruments software are warranted not to fail to execute programming
instructions, due to defects in materials and workmanship, for a period of 90 days from date of shipment, as evidenced
by receipts or other documentation. National Instruments will, at its option, repair or replace software media that do not
execute programming instructions if National Instruments receives notice of such defects during the warranty period.
National Instruments does not warrant that the operation of the software shall be uninterrupted or error free.
A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside
of the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping costs
of returning to the owner parts which are covered by warranty.
National Instruments believes that the information in this 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 APARTICULAR PURPOSE. CUSTOMER’SRIGHT TO RECOVER DAMAGES CAUSED
BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE
CUSTOMER. NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS,
OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF. This limitation of the liability of
National Instruments will apply regardless of the form of action, whether in contract or tort, including negligence.
Any action against National Instruments must be brought within one year after the cause of action accrues. National
Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control. The warranty
provided herein does not cover damages, defects, malfunctions, or service failures caused by owner’s failure to follow
the National Instruments installation, operation, or maintenance instructions; owner’s 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
CVI™, LabVIEW™, natinst.com™, NI-DAQ™, NI-SWITCH™, PXI™, and SCXI™are trademarks of National
Instruments Corporation.
Product 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 performed by properly trained and qualified medical personnel, and all traditional medical safeguards,
equipment, and procedures thatare appropriate in the particular situation to prevent serious injury ordeath 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.

Compliance
FCC/DOC Radio Frequency Interference
Class A Compliance
This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance
with the instructions in this manual, may cause interference to radio and television reception. Classification
requirements are the same for the Federal Communications Commission (FCC) and the Canadian
Department of Communications (DOC). This equipment has been tested and found to comply with the
following two regulatory agencies:
Federal Communications Commission
This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant
to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. Operation of this equipment in a
residential area is likely to cause harmful interference in which case the user will be required to correct the
interference at his own expense.
Notices to User: Changes or modifications not expressly approved by National Instruments could void
the user’s authority to operate the equipment under the FCC Rules.
This device complies with the FCC rules only if used with shielded interface cables
of suitable quality and construction. National Instruments used such cables to test
this device and provides them for sale to the user. The use of inferior or nonshielded
interface cables could void the user’s authority to operate the equipment under the
FCC rules.
If necessary, consult National Instruments or an experienced radio/television technician for additional
suggestions. The following booklet prepared by the FCC may also be helpful: Interference to Home
Electronic Entertainment Equipment Handbook. This booklet is available from the U.S. Government
Printing Office, Washington, DC 20402.
Canadian Department of Communications
This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment
Regulations.
Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur
du Canada.

Conventions
The following conventions are used in this manual.
< > Angle brackets containing numbers separated by an ellipsis represent a
range of values associated with a port, bit, or signal name (for example,
ACH<0..7> stands for the signals ACH0 through ACH7).
»The »symbol leads you through nested menu items and dialog box options
to a final action. The sequence File»Page Setup»Options»Substitute
Fonts directs you to pull down the File menu, select the Page Setup item,
select Options, and finally select the Substitute Fonts options from the
last dialog box.
This icon to the left of bold italicized text denotes a note, which alerts you
to important information.
This icon to the left of bold italicized text denotes a caution, which advises
you of precautions to take to avoid injury, data loss, or a system crash.
This icon to the left of bold italicized text denotes a warning, which advises
you of precautions to take to avoid being electrically shocked.
bold Bold text denotes the names of menus, menu items, parameters, dialog
boxes, dialog box buttons or options, icons, windows, Windows 95 tabs,
or LEDs.
bold italic Bold italic text denotes a note, caution, or warning.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text from which you supply the
appropriate word or value, as in CHx.
monospace Text in this font denotes text or characters that you should literally 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 for statements and
comments taken from programs.
!

© National Instruments Corporation vii SCXI-1127 User Manual
Contents
Chapter 1
Installing and Configuring the SCXI-1127
Installing the Software...................................................................................................1-2
Installing the Hardware..................................................................................................1-3
Installing the SCXI-1127 Module into the SCXI Chassis...............................1-3
Connecting the SCXI-1127 to the NI-DMM in a Single Chassis System.......1-4
Single 4-Slot Chassis Configuration.................................................1-5
Single 12-Slot Chassis Configuration...............................................1-7
Connecting the SCXI-1127 to the NI-DMM in a Multi-Chassis System........1-9
4-Slot and 4-Slot Multi-Chassis Configuration ................................1-9
4-Slot and 12-Slot Multi-Chassis Configuration ..............................1-11
12-Slot and 12-Slot Multi-Chassis Configuration ............................1-13
Connecting the SCXI-1127 to the NI-DMM in a PXI-1010 Chassis..............1-15
NI-DMM in PXI Slots 1 through 3 Configuration............................1-15
NI-DMM in PXI Slot 4 Configuration..............................................1-16
Accessing the SCXI-1127 through Other SCXI Modules
Using a DAQ Device....................................................................................1-16
Connecting the SCXI-1127 to an External DMM...........................................1-18
Configuration and Self-Test...........................................................................................1-20
Auto-Detecting Modules.................................................................................1-20
Manually Adding Modules..............................................................................1-21
Safety Information.........................................................................................................1-22
Chapter 2
Using the SCXI-1127
Operating as a Multiplexer/Scanner ..............................................................................2-1
Two-Wire Channel Scanning Configuration...................................................2-3
One-Wire Channel Scanning Configuration ...................................................2-5
Four-Wire Channel Scanning Configuration...................................................2-6
Four-Wire versus Two-Wire Resistance Measurement ..................................2-9
Mixed Mode Configuration.............................................................................2-10
Hardware and Software Scanning...................................................................2-11
Hardware Timed Scanning................................................................2-12
Software Scanning ............................................................................2-16
Making Temperature Measurements...............................................................2-17
Making Thermocouple Measurements..............................................2-17
Making RTD Measurements.............................................................2-19
Making Thermistor Measurements...................................................2-19

Contents
SCXI-1127 User Manual viii
© National Instruments Corporation
Operating as a Matrix....................................................................................................2-19
32x1 Matrix Configuration .............................................................................2-20
8x4 Matrix Configuration ...............................................................................2-21
Matrix Expansion............................................................................................2-24
Independent Mode.........................................................................................................2-29
Appendix A
Specifications
Appendix B
Accessories
Appendix C
Customizing Your Module
Appendix D
SCXI-1127 Front Connector
Appendix E
Common Questions
Appendix F
Technical Support Resources
Glossary
Index
Figures
Figure 1-1. Installing the SCXI-1127 into an SCXI Chassis.....................................1-3
Figure 1-2. 4-Slot Single Chassis Installation ...........................................................1-5
Figure 1-3. 4-Slot Configuration Parts Locator Diagram..........................................1-6
Figure 1-4. 12-Slot Single Chassis Installation .........................................................1-7
Figure 1-5. 12-Slot Configuration Parts Locator Diagram........................................1-8
Figure 1-6. 4-Slot to 4-Slot Multi-Chassis Configuration
Parts Locator Diagram............................................................................1-10

Contents
© National Instruments Corporation ix SCXI-1127 User Manual
Figure 1-7. 4-Slot to 12-Slot Multi-Chassis Configuration
Parts Locator Diagram.............................................................................1-12
Figure 1-8. 12-Slot to 12-Slot Multi-Chassis Configuration
Parts Locator Diagram.............................................................................1-14
Figure 1-9. Installing the SCXI-1127 with Two DAQ Devices.................................1-18
Figure 2-1. SCXI-1331 Signal Connections ..............................................................2-2
Figure 2-2. Two-Wire Block Diagram.......................................................................2-3
Figure 2-3. Two-Wire Wiring Diagram.....................................................................2-4
Figure 2-4. One-Wire Block Diagram .......................................................................2-5
Figure 2-5. One-Wire Wiring Diagram......................................................................2-6
Figure 2-6. Four-Wire Block Diagram.......................................................................2-7
Figure 2-7. Four-Wire Wiring Diagram.....................................................................2-8
Figure 2-8. Signal Connections for a Two-Wire Resistance Measurement...............2-9
Figure 2-9. Signal Connections for a Four-Wire Resistance Measurement...............2-10
Figure 2-10. Mixed Mode Scanning with an SCXI-1331............................................2-11
Figure 2-11. Hardware Scanning Flowchart................................................................2-13
Figure 2-12. Cabling an NI-DMM and Using the TRIG0 to Bus
the VMC/EXT_TRIG_IN to Non-Cabled Modules................................2-14
Figure 2-13. Cabling an External DMM......................................................................2-15
Figure 2-14. Daisy-Chained for Handshaking.............................................................2-16
Figure 2-15. Connecting an External DMM to an SCXI-1127
in an SCXI-2000 Series Chassis..............................................................2-16
Figure 2-16. Temperature Measurement Wiring Diagram ..........................................2-17
Figure 2-17. 4x2 One-Wire Matrix Configuration.......................................................2-20
Figure 2-18. 32x1 Matrix Wiring Diagram..................................................................2-21
Figure 2-19. SCXI-1332 Terminal Block ....................................................................2-22
Figure 2-20. SCXI-1332 Connected to an SCXI-1127................................................2-23
Figure 2-21. SCXI-1332 Connected to an SCXI-1127 Schematic ..............................2-24
Figure 2-22. 8x8 Matrix Parts Locator Diagram..........................................................2-25
Figure 2-23. 8x8 Matrix Schematic .............................................................................2-26
Figure 2-24. 16x8 Matrix Parts Locator Diagram........................................................2-27
Figure 2-25. 16x8 Matrix Schematic ...........................................................................2-28
Figure 2-26. SCXI-1127 Relay Configuration.............................................................2-30
Figure C-1. Removing the SCXI Module Cover........................................................C-1
Figure C-2. Bent and Trimmed Resistor.....................................................................C-2
Figure D-1. SCXI-1127 Front Connector Pin Assignments
for Two-Wire Mode ................................................................................F-2
Figure D-2. SCXI-1127 Front Connector Pin Assignments
for One-Wire Mode.................................................................................F-3

Contents
SCXI-1127 User Manual x
© National Instruments Corporation
Figure D-3. SCXI-1127 Front Connector Pin Assignments
for Four-Wire Mode................................................................................ F-4
Figure D-4. SCXI-1127 Front Connector Pin Assignments
to Create an 8x4 Matrix ..........................................................................F-5
Tables
Table 1-1. SCXI-1127 Configuration.......................................................................1-1
Table D-1. Front Connector Signal Description ......................................................F-6

© National Instruments Corporation 1-1 SCXI-1127 User Manual
1
Installing and Configuring the
SCXI-1127
The SCXI-1127 module is a high-voltage multiplexer/matrix module. It is
a high-density armature relay module that provides a 32x1, two-wire
multiplexer and several switch matrix configurations on an SCXI platform.
The SCXI-1127 can also operate as two 16x1 or four 8x1, two-wire
multiplexers allowing a single module to handle several multiplexing
needs.
Through software-configurable switches, the module can also operate as a
one-wire 64x1 multiplexer, enabling you to make a large number of
common referenced measurements. It can also operate as a 16x1, four-wire
multiplexer to make resistive measurements such as those needed for
thermistors and RTDs. With the use of special terminal blocks, the
SCXI-1127 can become an 8x4 or 32x1, two-wire matrix. A complete list
of possible configurations is given in Table 1-1.
To handle large channel counts, you can expand the size of the multiplexer
with additional SCXI-1127 modules. These modules support the analog
bus through a special adapter, the high-voltage analog bus (HVAB)
backplane adapter in the SCXI-1357/1358 kit, at the rear of the module.
This adapter allows you to expand the HVAB without complicated wiring.
For example, you can connect two SCXI-1127 modules using the
HVAB-backplane adapter to create a 64x1, two-wire multiplexer.
In a matrix configuration, you can expand the columns of the matrix using
the HVAB-backplane adapter. For example, you can connect two
Table 1-1. SCXI-1127 Configuration
Scanning
Configuration Multiplexer Matrix
One-wire 64x1 N/A
Two-wire 32x1 8x4 (Also 16x2, 32x1)
Four-wire 16x1 N/A