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

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©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
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provided herein does not cover damages, defects, malfunctions, or service failures caused by owner’s failure to follow
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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
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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

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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

Chapter 1 Installing and Configuring the SCXI-1127
SCXI-1127 User Manual 1-2
© National Instruments Corporation
SCXI-1127 modules via the HVAB-backplane adapter to create a 16x4
matrix. You can also expand the rows and columns of a matrix through the
front connector of the SCXI-1127 using the SCXI-1332 and matrix
expansion cables. Refer to Chapter 2, Matrix Expansion,for further
information on matrix expansion.
The SCXI-1127 is designed to work well at both low and high voltages. For
low-voltage measurements such as those taken with thermocouples, the
SCXI-1127 uses relays with very low thermal offset to ensure accurate
measurements. At high voltages, the SCXI-1127 can handle signals up to
250 Vrms at a 200 mA load and 30 VDC at a 1 A load. The SCXI-1127
complies with the CE low-voltage directive for an installation category II
environment. Refer to Appendix A, Specifications, for detailed
specifications of the SCXI-1127.
The following section explains how to install the software required to use
the SCXI-1127, including installing the latest version of NI-SWITCH.
After installing the software, install the SCXI-1127 hardware and its
accessories, then configure and test the SCXI-1127.
Installing the Software
You can control the SCXI-1127 programmatically in an application
development environment (ADE) using NI-SWITCH. The supported
ADEs include LabVIEW, LabWindows/CVI, Visual Basic, and C or C++
environments. The following instructions describe the order for installing
the software for your SCXI-1127.
1. Installyour ADE if you havenotalready done so. National Instruments
ADEs have release notes containing their software installation
instructions.
2. Install the NI-SWITCH software that came on a CD with your
SCXI-1127. The CD includes the software required to configure and
program your SCXI-1127 module.
a. Insert your National Instruments NI-SWITCH software CD into
the CD-ROM drive.
b. Click on the Install NI-SWITCH Software option in the
installation window. The installer guides you through the rest of
the installation process.

Chapter 1 Installing and Configuring the SCXI-1127
© National Instruments Corporation 1-3 SCXI-1127 User Manual
Installing the Hardware
The following section describes how to install your SCXI-1127 for use
with SCXI chassis, National Instruments DAQ devices, and National
Instruments DMMs.
Installing the SCXI-1127 Module into the SCXI Chassis
You need the following items to complete the installation:
• SCXI-1127
• SCXI chassis
• 1/8 in. flathead screwdriver
Follow these steps to install your SCXI-1127 module into the SCXI chassis
while referring to Figure 1-1.
Figure 1-1. Installing the SCXI-1127 into an SCXI Chassis
1 AB0+
2 AB0-
3 NI 4060 for PCI
4AB2+
5AB2-
6 HV8-BAN4
7SH9MD-9MD
8 2-Slot HVAB-Backplane
Adapter
9 SCXI Chassis
10 SCXI-1127 Module
2
3
4
5
6
7
8
9
10
1

Chapter 1 Installing and Configuring the SCXI-1127
SCXI-1127 User Manual 1-4
© National Instruments Corporation
1. Turn off the computer that contains the DAQ/DMM device or
disconnect it from your SCXI chassis.
2. Turn off the SCXI chassis. Do not insert the SCXI-1127 module into a
chassis that is turned on.
3. Insert the SCXI-1127 module into the rightmost slot. Gently guide the
module into the module guides and push it to the back of the slot until
the connectors make good contact. The module must be firmly
engaged; however do not force the module into place.
Note When installing the SCXI-1127 module in an SCXI chassis, the rightmost slot
(when the chassis is viewed from the front) must be filled first, then fill the slot to
the left with the next SCXI-1127. Other SCXI modules can be loaded from left to
right.
4. Insert any other SCXI modules into the remaining slots in the same
manner as described in step 3.
5. Secure all the SCXI-1127 modules to the SCXI chassis using both
thumbscrews.
To finish installing your SCXI-1127, follow one of the procedures in the
appropriate section below.
Connecting the SCXI-1127 to the NI-DMM in a Single Chassis System
You need the following items for this installation:
• SCXI-1000/1000DC/1001 chassis with the SCXI-1127 modules
installed
• SCXI-1357 (4-slot)/1358 (12-slot) kit
– 1-slot, 2-slot, and/or 8-slot HVAB-backplane adapter
– HV8-to-BAN4 cable
– SH9MD-9MD cable
– Two or three 8-position high-voltage plugs
•NI-DMM
• 1/8 in. flathead screwdriver
Consult your SCXI chassis documentation and NI-DMM documentation
foradditional instructions and warnings. YourSCXI-1127 modules and any
other SCXI modules should already be installed in the chassis according to
their installation instructions. To connect the SCXI-1127 module with an
NI-DMM, follow the steps in the following section that best describes your

Chapter 1 Installing and Configuring the SCXI-1127
© National Instruments Corporation 1-5 SCXI-1127 User Manual
test system. Before you proceed with your connections, make sure you turn
off your SCXI chassis.
Single 4-Slot Chassis Configuration
Refer to Figure 1-2 and 1-3 to make connections in the single 4-slot chassis
configuration.
Figure 1-2. 4-Slot Single Chassis Installation
1 SCXI-1127 Module
2 4-Slot SCXI Chassis
3 2-Slot HVAB-Backplane
Adapter
4 1-Slot HVAB-Backplane
Adapter
5 8-Position HVAB Plug
6 NI 4060 for PCI
7 SH9MD-9MD Cable
8 HV8-BAN4 Cable
7
8
1
345
26

Chapter 1 Installing and Configuring the SCXI-1127
SCXI-1127 User Manual 1-6
© National Instruments Corporation
Figure 1-3. 4-Slot Configuration Parts Locator Diagram
1. Install the 2-slot HVAB-backplane adapter behind slots 3 and 4.
2. Install additional 1-slot HVAB-backplane adapters behind slots 1
and 2 if needed.
3. Install the 8-position HVAB plugs to connect the HVAB-backplane
adapters as needed.
4. Connect the HV8-BAN4 cable from the DMM to the HVAB connector
behind slot 4.
5. Connect the SH9MD-9MD cable from the DMM to the AUX IN
connector.
6. You can install any additional SCXI-1127 modules in any slot that has
an HVAB-backplane adapter behind it.
Note An SCXI-1127 is required in slot 4 to establish communication with the chassis.
Ifslot4 isempty,the system willnot operate.It is thismodulethatyou mustspecify
in the configuration utility as the cabled module to the DMM.
1 2-Slot HVAB-Backplane
Adapter
2 8-Position HVAB Plug
3 1-Slot HVAB-Backplane
Adapter
4 HV8-BAN4 Cable
5 NI 4060 for PCI
6 SH9MD-9MD Cable
7 4-Slot SCXI Chassis
AB0+
AB0–
AB2+
AB2–
5
6
7
24
13

Chapter 1 Installing and Configuring the SCXI-1127
© National Instruments Corporation 1-7 SCXI-1127 User Manual
Single 12-Slot Chassis Configuration
Refer to Figure 1-4 and 1-5 to make connections in the single 12-slot
chassis configuration.
Figure 1-4. 12-Slot Single Chassis Installation
1 SCXI-1127 Module
2 12-Slot SCXI Chassis
3 2-Slot HVAB-Backplane
Adapter
4 1-Slot HVAB-Backplane
Adapter
5 8-Position HVAB Plug
6 NI 4060 for PCI
7 SH9MD-9MD Cable
8 HV8-BAN4 Cable
9 8-Slot HVAB-Backplane Adapter
97
8
1
345
2
6

Chapter 1 Installing and Configuring the SCXI-1127
SCXI-1127 User Manual 1-8
© National Instruments Corporation
Figure 1-5. 12-Slot Configuration Parts Locator Diagram
1. Install the 8-slot HVAB-backplane adapter behind slots 5 through 12.
2. Install additional 2-slot and 1-slot HVAB-backplane adapters behind
slots 1 through 4 if needed.
3. Install the 8-position HVAB plugs to connect the HVAB-backplane
adapters as needed.
4. Connect the HV8-BAN4 cable from the DMM to the HVAB connector
behind slot 12.
5. Connect the SH9MD-9MD cable from the DMM to the AUX IN
connector behind slot 5.
6. You can install any additional SCXI-1127 modules in any slot that has
an HVAB-backplane adapter behind it.
Note Do not connect the SH9MD-9MD cable to the AUX IN connector behind slot 4 on
the 2-slot HVAB-backplane adapter.
An SCXI-1127 is required in slot 12 to establish communications with the chassis.
If slot 12 is empty, the system will not operate. It is this module that you must
specify in the configuration utility as the cabled module to the DMM.
1 8-Slot HVAB-Backplane Adapter
2 HV8-BAN4 Cable
3 8-Position HVAB Plug
4 2-Slot HVAB-Backplane
Adapter
5 1-Slot HVAB-Backplane
Adapter
6 NI 4060 for PCI
7 SH9MD-9MD Cable
8 12-Slot SCXI Chassis
AB0+
AB0–
AB2+
AB2–
6
87
1 32 4 5

Chapter 1 Installing and Configuring the SCXI-1127
© National Instruments Corporation 1-9 SCXI-1127 User Manual
Connecting the SCXI-1127 to the NI-DMM in a Multi-Chassis System
The following sections describe how to configure the following
multi-chassis configurations:
• 4-slot and 4-slot multi-chassis configuration
• 4-slot and 12-slot multi-chassis configuration
• 12-slot and 12-slot multi-chassis configuration
You can also create larger configurations.
4-Slot and 4-Slot Multi-Chassis Configuration
In addition to the items needed for a single chassis system, you need the
following to install this configuration:
• SCXI-1357 multi-chassis expansion kit
– HV8-HV8 cable
– SH9MD-9MD cable
– Two 8-position HVAB plugs
– One 2-slot HVAB-backplane adapter
– Two 1-slot HVAB-backplane adapters

Chapter 1 Installing and Configuring the SCXI-1127
SCXI-1127 User Manual 1-10
© National Instruments Corporation
Refer to Figure 1-6 to setup this multi-chassis configuration.
Figure 1-6. 4-Slot to 4-Slot Multi-Chassis Configuration Parts Locator Diagram
1. Install the HVAB-backplane adapters and 8-position HVAB plugs in
the next chassis as described in steps 1 through 3 in Single 4-Slot
Chassis Configuration.
2. Connect the HV8-HV8 cable from the first chassis, normally the
connector behind slot 1, to the HVAB connector (behind slot 4) of the
next chassis.
1 2-Slot HVAB-Backplane
Adapter
2 8-Position HVAB Plug
3 1-Slot HVAB-Backplane
Adapter
4 HV8-BAN4 Cable
5 NI 4060 for PCI
6 SH9MD-9MD Cable
7 4-Slot SCXI Chassis
8 SH9MD-9MD Cable
9 HV8-HV8 Cable
10 4-Slot SCXI Chassis
AB0+
AB0–
AB2+
AB2–
5
6
10
8
9
7
4
1 2 3

Chapter 1 Installing and Configuring the SCXI-1127
© National Instruments Corporation 1-11 SCXI-1127 User Manual
3. Connect the SH9MD-9MD cable from the AUX OUT connector of the
first chassis to the AUX IN connector of the next chassis.
4. Repeat steps 1 through 3 for each additional chassis.
Note An SCXI-1127 is required in slot 4 to establish communications with the chassis.
Ifslot4 isempty,the system willnot operate.It is thismodulethatyou mustspecify
in the configuration utility as the cabled module to the DMM.
Ifa chassisisconfigured withless thanfour slots ofthe HVAB-backplaneadapter,
use the right-most available HVAB connector to extend to the next chassis. In this
instance,right-mostmeans the slotclosesttoslot1 when the chassisisviewedfrom
the back.
4-Slot and 12-Slot Multi-Chassis Configuration
In addition to the items needed for a single chassis system, you need the
following items to install this configuration:
• SCXI-1358 multi-chassis expansion kit
– HV8-HV8 cable
– SH9MD-9MD cable
– Three 8-position HVAB plugs
– One 8-slot HVAB-backplane adapter
– One 2-slot HVAB-backplane adapter
– Two 1-slot HVAB-backplane adapters