National Instruments AMUX-64T User manual

© Copyright 1989, 1994 National Instruments Corporation.
All Rights Reserved.
AMUX-64T
User Manual
Analog Multiplexer with Temperature Sensor
November 1994 Edition
Part Number 320253B-01

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Limited Warranty
The AMUX-64T 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,
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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
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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.

© National Instruments Corporation v AMUX-64T User Manual
Contents
About This Manual.............................................................................................................ix
Organization of This Manual.........................................................................................ix
Conventions Used in This Manual.................................................................................x
Chapter 1
Introduction..........................................................................................................................1-1
About the AMUX-64T...................................................................................................1-1
What You Need to Get Started ......................................................................................1-1
Software Programming Choices........................................................................1-2
LabVIEW and LabWindows Application Software..........................................1-2
NI-DAQ Driver Software...................................................................................1-2
Register-Level Programming.............................................................................1-5
Optional Equipment.......................................................................................................1-5
Unpacking......................................................................................................................1-6
Chapter 2
Configuration and Installation.......................................................................................2-1
Board Configuration ......................................................................................................2-1
Power, Tempeture Sensor, and Shield Configuration........................................2-1
Supplementary Configuration Information........................................................2-4
Power Supply Selection.........................................................................2-4
Temperature Sensor...............................................................................2-5
Shield Selection......................................................................................2-5
Single-Board and Multiple-Board Configurations.........................................................2-7
Single-Board Configuration...............................................................................2-9
Two-Board Configuration..................................................................................2-9
Four-Board Configuration..................................................................................2-9
Installation......................................................................................................................2-10
Power-On Sequence.......................................................................................................2-11
Chapter 3
Signal Connections.............................................................................................................3-1
I/O Connector.................................................................................................................3-2
Differential Connections................................................................................................3-4
Using the AMUX-64T for Thermocouple Measurements.............................................3-4
Selecting the Gain and Input Ranges.................................................................3-4
Linearizing the Data...........................................................................................3-5
Differential Measurements.................................................................................3-6
An Example of Using Thermocouples (Differential) ........................................3-7
Procedure 1 ............................................................................................3-7
Procedure 2 ............................................................................................3-8
Comments..............................................................................................3-8
Single-Ended Measurement...............................................................................3-9
Using More Than One AMUX-64T...................................................................3-9
Sources of Error.................................................................................................3-9
Thermocouple Measurement Accuracies...........................................................3-10
Other Connection Considerations..................................................................................3-10

Contents
AMUX-64T User Manual vi © National Instruments Corporation
Chapter 4
Signal Conditioning............................................................................................................4-1
Analog Input ..................................................................................................................4-1
Application Notes ..........................................................................................................4-3
Soldering and Desoldering on the AMUX-64T Board......................................4-3
Channel Configurations.....................................................................................4-3
Connecting Nonreferenced or Floating Signal Sources.....................................4-4
Differential Inputs..................................................................................4-4
Single-Ended Inputs...............................................................................4-5
Connecting Ground-Referenced Signal Sources................................................4-5
Differential Inputs..................................................................................4-5
Single-Ended Inputs...............................................................................4-5
Building Lowpass Filters...................................................................................4-6
Building Highpass Filters...................................................................................4-7
Building Attenuators (Voltage Dividers)...........................................................4-9
Chapter 5
Theory of Operation and Register-Level Programming......................................5-1
Functional Overview......................................................................................................5-1
How to Address AMUX-64T Analog Input Channels...................................................5-3
A/D Conversions on a Single AMUX-64T Analog Input Channel...................5-3
Automatic Channel Scanning with the AMUX-64T......................................................5-6
Scanning Order ..............................................................................................................5-9
Programming Channel Scanning with the AMUX-64T ................................................5-10
Initialize the AMUX-64T Scanning Counter.....................................................5-10
Configure Counter 1 to Control the MIO Scanning Clock................................5-10
Set the SCAN DIV Bit in MIO Command Register 1.......................................5-11
Appendix A
Specifications........................................................................................................................ A-1
Appendix B
Customer Communication...............................................................................................B-1
Glossary......................................................................................................................Glossary-1
Index..................................................................................................................................Index-1

Contents
© National Instruments Corporation vii AMUX-64T User Manual
Figures
Figure 1-1. The Relationship between the Programming Environment,
NI-DAQ, and Your Hardware ...............................................................................1-4
Figure 2-1. AMUX-64T Parts Locator Diagram ......................................................................2-2
Figure 2-2. Daisy-Chaining Multiple AMUX-64T Boards ......................................................2-8
Figure 2-3. Cable Positioning for the AMUX-64T...................................................................2-10
Figure 3-1. AMUX-64T Signal Routing...................................................................................3-3
Figure 4-1. Onboard Equivalent Circuit ...................................................................................4-1
Figure 4-2. Bias Return Resistor for DC-Coupled Floating Source on Channel 1...................4-4
Figure 4-3. Normalized Frequency Response of Lowpass Filter..............................................4-6
Figure 4-4. Lowpass Filter on Differential Channel 1..............................................................4-7
Figure 4-5. Normalized Frequency Response of Highpass Filter.............................................4-8
Figure 4-6. Highpass Filter on Differential Channel 1.............................................................4-9
Figure 4-7. Attenuator for Use with Differential Inputs...........................................................4-10
Figure 5-1. AMUX-64T Block Diagram..................................................................................5-2
Figure 5-2. Scanning Counter Control Bits ..............................................................................5-3
Figure 5-3. AMUX-64T Channel Address Mapping................................................................5-5
Figure 5-4. Two-Level Multiplexer Arrangement Showing Channel 9 Selected.....................5-7
Figure 5-5. Scanning Order for Different AMUX-64T Board Configurations.........................5-8
Tables
Table 2-1. Power Supply Selection...........................................................................................2-3
Table 2-2. Temperature Sensor Selection.................................................................................2-3
Table 2-3. Shield Selection.......................................................................................................2-4
Table 2-4. MIO Board Power Budget.......................................................................................2-5
Table 2-5. Single- and Multiple- Board Configuration.............................................................2-7
Table 2-6. Channel Ranges for Multiple AMUX-64T Boards.................................................2-8
Table 2-7. U12 Switch Settings for Two-Board Configuration................................................2-9
Table 2-8. U12 Switch Settings for Four-Board Configuration................................................2-10
Table 3-1. Pin Mapping for I/O Connectors J1, J2, and J42.....................................................3-2
Table 3-2. Thermocouple Voltage Output Extremes (mV)......................................................3-5
Table 3-3. NBS Polynomial Coefficients .................................................................................3-6
Table 3-4. Thermocouple Measurement Accuracies................................................................3-10
Table 4-1. Component Positions in Each Channel ...................................................................4-2
Table 5-1. AMUX-64T Channel Selection...............................................................................5-4
Table 5-2. Multiple AMUX-64T Board Addressing ................................................................5-5
Table 5-3. AMUX-64T Scanning Order for Each MIO Board Input Channel.........................5-9

© National Instruments Corporation ix AMUX-64T User Manual
About This Manual
This manual describes the mechanical and electrical aspects of the AMUX-
64T and contains information about configuring, operating, and
programming the AMUX-64T. The AMUX-64T is a front-end analog
multiplexer that quadruples the number of analog input signals that can be
digitized with a National Instruments MIO board (except the AT-MIO-64).
The AMUX-64T also has an integrated circuit temperature sensor that can
be connected as a differential input to two of the 64 input channels
(jumper-selectable) for low-cost thermocouple cold junction compensation.
The AMUX-64T also has signal conditioning positions available for all 64
input channels.
Organization of This Manual
The AMUX-64T User Manual is organized as follows:
• Chapter 1, Introduction, describes the AMUX-64T; lists what you need
to get started with your AMUX-64T; describes the software
programming choices and optional equipment; and explains how to
unpack your AMUX-64T.
• Chapter 2, Configuration and Installation, describes the configuration
and installation of your AMUX-64T. The topics discussed include switch
and jumper configuration, connection of the AMUX-64T board to the
MIO board, power, and signal connections.
• Chapter 3, Signal Connections, describes the AMUX-64T signal
connections and has specifications and connection instructions for the
AMUX-64T connector signals.
• Chapter 4, Signal Conditioning, discusses signal conditioning and
describes how to build systems such as filters and attenuators for
passive analog input signal conditioning.
• Chapter 5, Theory of Operation and Register-Level Programming,
contains a functional overview of the AMUX-64T and explains the
operation of each functional unit making up the AMUX-64T. This

About This Manual
AMUX-64T User Manual x © National Instruments Corporation
chapter also contains register-level programming information for the
MIO board.
• Appendix A, Specifications, lists the specifications for the AMUX-64T.
• Appendix B, Customer Communication, contains forms you can use to
request help from National Instruments or to comment on our products
and manuals.
• The Glossary contains an alphabetical list and description of terms used
in this manual, including abbreviations, acronyms, metric prefixes,
mnemonics, and symbols.
• The Index contains an alphabetical list of key terms and topics in this
manual, including the page where you can find each one.

About This Manual
© National Instruments Corporation xi AMUX-64T User Manual
Conventions Used in This Manual
The following conventions are used in this manual:
bold italic Bold italic text denotes a note, caution, or warning.
italic Italic text denotes emphasis, a cross reference, or an
introduction to a key concept.
E Series E Series refers to the AT-MIO-16E-2, AT-MIO-16E-10,
AT-MIO-16DE-10, AT-MIO-16XE-10, and NEC-MIO-16E-4
boards.
MC MC refers to the Micro Channel Series computers.
MIO board MIO board refers to the AT-MIO-16, AT-MIO-16D,
AT-MIO-16DE-10, AT-MIO-16E-2, AT-MIO-16E-10, AT-
MIO-16F-5, AT-MIO-16X, AT-MIO-16XE-10, MC-MIO-16,
NB-MIO-16, NB-MIO-16X, NEC-MIO-16E-4, and SB-MIO-
16E-4 boards.
monospace Text in this font denotes text or characters that are to be
literally input from the keyboard, sections of code,
programming examples, and syntax examples. This font
is also used for the proper names of disk drives, paths,
directories, programs, subprograms, subroutines, device
names, functions, variables, filenames, and extensions,
and for statements and comments taken from program
code.
NB NB refers to the NuBus series computers.
PC PC refers to the IBM PC/XT, the IBM PC AT, and
compatible computers.
Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and terms
are listed in the Glossary.

About This Manual
AMUX-64T User Manual xii © National Instruments Corporation
National Instruments Documentation
The AMUX-64T User Manual is one piece of the documentation set for your
system. You could have any of several types of manuals, depending on the
hardware and software in your system. Use the different types of manuals
you have as follows:
• Your DAQ hardware user manuals—These manuals have detailed
information about the DAQ hardware that plugs into or is connected to
your computer. Use these manuals for hardware installation and
configuration instructions, specification information about your DAQ
hardware, and application hints.
• Software manuals—Examples of software manuals you may have are the
LabVIEW and LabWindows®manual sets and the NI-DAQ manuals.
After you set up your hardware system, use either the application
software (LabVIEW or LabWindows) manuals or the
NI-DAQ manuals to help you write your application. If you have a large
and complicated system, it is worthwhile to look through the software
manuals before you configure your hardware.
• Accessory installation guides or manuals—If you are using accessory
products, read the terminal block and cable assembly installation guides
or accessory board user manuals. They explain how to physically
connect the relevant pieces of the system. Consult these guides when
you are making your connections.
Related Documentation
The following manuals contain information you may find helpful as you
read this manual:
•NIST Monograph 175: Temperature-Electromotive Force Reference
Functions and Tables for the Letter-Designated Thermocouple Types
Based on the ITS-90, National Institute of Standards and Technology,
1993
The following document contains information you may find helpful as you
read this manual and is available from National Instruments upon request:
• Application Note 043, Measuring Temperature with Thermocouples

About This Manual
© National Instruments Corporation xiii AMUX-64T User Manual
In addition, the National Instruments DAQ board user manuals contain
information you may find helpful as you read this manual.
Customer Communication
National Instruments wants to receive your comments on our products and manuals. We are
interested in the applications you develop with our products, and we want to help if you have
problems with them. To make it easy for you to contact us, this manual contains comment and
configuration forms for you to complete. These forms are in Appendix B, Customer
Communication, at the end of this manual.

© National Instruments Corporation 1-1 AMUX-64T User Manual
Chapter 1
Introduction
This chapter describes the AMUX-64T; lists what you need to get started with your AMUX-64T;
describes the software programming choices and optional equipment; and explains how to
unpack your AMUX-64T.
About the AMUX-64T
The AMUX-64T is a front-end analog multiplexer that quadruples the number of analog input
signals that can be digitized with a National Instruments MIO board (except the AT-MIO-64).
The AMUX-64T has 16 separate four-to-one analog multiplexer circuits. Four AMUX-64T
boards can be cascaded to digitize up to 256 single-ended or 128 differential signals by one
MIO board.
The AMUX-64T has an integrated circuit temperature sensor that can be connected as a
differential input to two of the 64 input channels (jumper-selectable) for low-cost thermocouple
cold-junction compensation. Cold-junction compensation is achieved by adding the temperature
reading of the sensor to the temperature readings of thermocouples at the remaining 62
AMUX-64T input channels. You can cascade up to four AMUX-64T boards to increase the
number of thermocouple inputs with cold-junction compensation to 248 in single-ended mode or
124 in differential mode.
The AMUX-64T also has open component positions on all 64 input channels. These positions
are for building signal conditioning devices such as filters and attenuators.
Note: When an MIO board is referred to without an AT, MC, NB, NEC, or SB prefix, the
reference applies to the AT, MC, NB, NEC, and SB versions of that board.
The AMUX-64T is a circuitboard assembly that is placed on a workbench or mounted in a 19-in.
rack. You can configure the AMUX-64T to draw power from the MIO board or from an external
+5 V supply. A red LED indicates when the board is powered on. Input signal leads are
attached at screw terminals.
What You Need to Get Started
To set up and use your AMUX-64T, you will need the following:
AMUX-64T board
AMUX-64T User Manual
0.2, 0.5, 1.0, or 2.0 m cable
MIO board
Detailed specifications of the AMUX-64T are listed in Appendix A, Specifications.

Introduction Chapter 1
AMUX-64T User Manual 1-2 © National Instruments Corporation
Software Programming Choices
There are four options to choose from when programming your National Instruments DAQ and
SCXI hardware. You can use LabVIEW, LabWindows, NI-DAQ, or register-level programming
software.
Your accessory hardware kit does not include software. The AMUX-64T works with LabVIEW
for Windows, LabVIEW for Macintosh, LabWindows for DOS, and LabWindows/CVI for
Windows, NI-DAQ for PC compatibles, and NI-DAQ for Macintosh.
LabVIEW and LabWindows Application Software
LabVIEW and LabWindows are innovative program development software packages for data
acquisition and control applications. LabVIEW uses graphical programming, whereas
LabWindows enhances traditional programming languages. Both packages include extensive
libraries for data acquisition, instrument control, data analysis, and graphical data presentation.
LabVIEW currently runs on four different platforms—AT/MC/EISA computers running
Microsoft Windows, NEC computers running Windows, the Macintosh platform, and the Sun
SPARCstation platform. LabVIEW features interactive graphics, a state-of-the-art user
interface, and a powerful graphical programming language. The LabVIEW Data Acquisition VI
Library, a series of VIs for using LabVIEW with National Instruments DAQ hardware, is
included with LabVIEW. The LabVIEW Data Acquisition VI Libraries are functionally
equivalent to the NI-DAQ software, except that the SCXI functions are not included in the
LabVIEW software for Sun.
LabWindows has two versions—LabWindows for DOS is for use on PCs running DOS, and
LabWindows/CVI is for use on PCs running Windows and for Sun SPARCstations.
LabWindows/CVI features interactive graphics, a state-of-the-art user interface, and uses the
ANSI standard C programming language. The LabWindows Data Acquisition Library, a series
of functions for using LabWindows with National Instruments DAQ hardware, is included with
the NI-DAQ software kit. The LabWindows Data Acquisition libraries are functionally
equivalent to the NI-DAQ software except that the SCXI functions are not included in the
LabWindows/CVI software for Sun.
Using LabVIEW or LabWindows software will greatly reduce the development time for your
data acquisition and control application.
NI-DAQ Driver Software
The NI-DAQ driver software is included at no charge with all National Instruments DAQ
hardware. NI-DAQ is not packaged with SCXI or accessory products, except for the
SCXI-1200. NI-DAQ has an extensive library of functions that you can call from your
application programming environment. These functions include routines for analog input
(A/D conversion), buffered data acquisition (high-speed A/D conversion), analog output
(D/A conversion), waveform generation, digital I/O, counter/timer operations, SCXI, RTSI,
self calibration, messaging, and acquiring data to extended memory.

Chapter 1 Introduction
© National Instruments Corporation 1-3 AMUX-64T User Manual
NI-DAQ has both high-level DAQ I/O functions for maximum ease of use and low-level data
acquisition I/O functions for maximum flexibility and performance. Examples of high-level
functions are streaming data to disk or acquiring a certain number of data points. An example of
a low-level function is writing directly to registers on the data acquisition device. NI-DAQ does
not sacrifice the performance of National Instruments data acquisition devices because it lets
multiple devices operate at their peak performance—up to 500 kS/s on ISA computers and up to
1 MS/s on EISA computers.
NI-DAQ includes a Buffer and Data Manager that uses sophisticated techniques for handling
and managing data acquisition buffers so that you can simultaneously acquire and process data.
NI-DAQ functions for the DAQCard-DIO-24 can transfer data using interrupts or software
polling.
With the NI-DAQ Resource Manager, you can simultaneously use several functions and several
DAQ devices. The Resource Manager prevents multiple-device contention over DMA channels,
interrupt levels, and RTSI channels.
NI-DAQ can send event-driven messages to DOS, Windows, or Windows NT applications
whenever a user-specified event occurs. Thus, polling is eliminated and you can develop event-
driven data acquisition applications. An example of an NI-DAQ user event is when a specified
digital I/O pattern is matched.
NI-DAQ also internally addresses many of the complex issues between the computer and the
DAQ hardware such as programming the PC interrupt and DMA controllers. NI-DAQ maintains
a consistent software interface among its different versions so that you can change platforms
with minimal modifications to your code.
Figure 1-1 illustrates the relationship between NI-DAQ and LabVIEW and LabWindows. You
can see that the data acquisition parts of LabVIEW and LabWindows are functionally equivalent
to the NI-DAQ software.

Introduction Chapter 1
AMUX-64T User Manual 1-4 © National Instruments Corporation
LabVIEW
(PC, Macintosh, or
Sun SPARCstation)
Conventional
Programming
Environment
(PC, Macintosh, or
Sun SPARCstation)
NI-DAQ
Driver Software
DAQ or
SCXI Hardware Personal
Computer
or
Workstation
Figure 1-1. The Relationship between the Programming Environment,
NI-DAQ, and Your Hardware
The National Instruments PC, AT, MC, DAQCard, and DAQPad Series DAQ hardware is
packaged with NI-DAQ software for PC compatibles. NI-DAQ software for PC compatibles
comes with language interfaces for Professional BASIC, QuickBASIC, Visual Basic, Borland
Turbo Pascal, Turbo C++, Borland C++, Microsoft Visual C++, and Microsoft C for DOS; and
Visual Basic, Turbo Pascal, Microsoft C with SDK, and Borland C++ for Windows and
Microsoft Visual C++ for Windows NT. You can use your AMUX-64T, together with other PC,
AT, MC, EISA, DAQCard, and DAQPad Series DAQ and SCXI hardware, with NI-DAQ
software for PC compatibles.
The National Instruments NB Series DAQ boards are packaged with NI-DAQ software for
Macintosh. NI-DAQ software for Macintosh comes with language interfaces for MPW C,
THINK C, Pascal, and Microsoft QuickBASIC. Any language that uses Device Manager
Toolbox calls can access NI-DAQ software for Macintosh. You can use NB Series DAQ boards
and SCXI hardware with NI-DAQ software for Macintosh.
The National Instruments SB Series DAQ boards are packaged with NI-DAQ software for Sun,
which comes with a language interface for ANSI C.

Chapter 1 Introduction
© National Instruments Corporation 1-5 AMUX-64T User Manual
Register-Level Programming
The final option for programming any National Instruments DAQ hardware is to write register-
level software. Writing register-level programming software can be very time-consuming and
inefficient, and is not recommended for most users. The only users who should consider writing
register-level software should meet at least one of the following criteria:
• National Instruments does not support your operating system or programming language.
• You are an experienced register-level programmer who is more comfortable writing your
own register-level software.
Even if you are an experienced register-level programmer, always consider using NI-DAQ,
LabVIEW, or LabWindows to program your National Instruments DAQ hardware. Using the
NI-DAQ, LabVIEW, or LabWindows software is easier than, and as flexible as, register-level
programming, and can save you weeks of development time.
The AMUX-64T User Manual and your software manuals contain complete instructions for
programming your AMUX-64T with NI-DAQ, LabVIEW, or LabWindows. For register-level
programming information, see Chapter 5, Theory of Operation and Register-Level
Programming. If you are using NI-DAQ with LabWindows, use this manual and your
LabWindows software manual. If you are using LabVIEW, use your LabVIEW manual. If you
are using NI-DAQ, LabVIEW, or LabWindows to control your board, you should not need the
programming information in Chapter 5, Theory of Operation and Register-Level Programming.
Chapter 5, Theory of Operation and Register-Level Programming,contains low-level
programming details, such as register maps, bit descriptions, and register programming hints,
that you will need only for register-level programming.
Optional Equipment
Contact National Instruments to order any of the following optional equipment:
• CB-50 I/O connector (50-screw terminals) with 0.5 or 1.0 m cable
• SCB-68 I/O connector (68-screw terminals) with 0.5 or 1.0 m cable
• SH6868 shielded cable assembly with 1, 2, 5, or 10 m cable
• SH6850 shielded cable assembly with 1, 2, 5, or 10 m cable
• R6868 1 m ribbon cable assembly
• R6850 1 m ribbon cable assembly
• Rack-mount kit with acrylic plastic cover (single- or double-height)
• Rack-mount kit with metal wraparound cover (single- or double-height)

Introduction Chapter 1
AMUX-64T User Manual 1-6 © National Instruments Corporation
For more information about optional equipment available from National Instruments, refer to
your National Instruments catalog or call the office nearest you.
Unpacking
Your AMUX-64T board is shipped in an antistatic package to prevent electrostatic damage to the
board. Electrostatic discharge can damage several components on the board. To avoid such
damage in handling the board, take the following precautions:
• Ground yourself via a grounding strap or by holding a grounded objects.
• Touch the antistatic package to a metal part of your computer chassis before removing the
board from the package.
• Remove the board from the package and inspect the board for loose components or any other
sign of damage. Notify National Instruments if the board appears damaged in any way. Do
not install or connect a damaged board in your computer or to your MIO board.
•Never touch the exposed pins of connectors.

© National Instruments Corporation 2-1 AMUX-64T User Manual
Chapter 2
Configuration and Installation
This chapter describes the configuration and installation of your AMUX-64T. The topics
discussed include switch and jumper configuration, connection of the AMUX-64T to the MIO
board, power, and signal connections.
Board Configuration
The AMUX-64T contains two sets of switches and three jumpers to change the multiplexer
settings and power connection configurations of the board. These jumpers and switches are
shown in Figure 2-1.
The five-position switch at U12 configures the AMUX-64T for single-board or multiple-board
operation. Switch SW1 selects either the internal +5 V power from the MIO board or an external
+5 V power source for the AMUX-64T. Jumper W1 optionally connects the onboard
temperature sensor to Channels 0 and 32 of the AMUX-64T. Jumper W2 connects the
AMUX-64T analog ground to the shield of a rack-mounted chassis. Jumper W3 connects the
AMUX-64T 68-pin connector shield to the shield of a rack-mounted chassis.
Power, Temperature Sensor, and Shield Configuration
To configure the AMUX-64T board, use the three user-configurable jumpers (W1–W3) shown in
the parts locator diagram, Figure 2-1. Tables 2-1 to 2-3 list the description and configuration of
the user-configurable jumpers.

Configuration and Installation Chapter 2
AMUX-64T User Manual 2-2 © National Instruments Corporation
1
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1 J41 5 U12 9 J1
2 SW1 6 Product Name and Assembly Number 10 J2
3 W3 7 Serial Number 11 J42
4 W2 8 W1 12 Temperature Sensor
Figure 2-1. AMUX-64T Parts Locator Diagram