National Instruments AT-MIO-16 Owners Manual

AT-MIO-16

User Manual

Multifunction I/O Board for the PC/AT

February 1995 Edition

Part Number 320476-01

© Copyright 1992, 1995 National Instruments Corporation.

All Rights Reserved.

National Instruments Corporate Headquarters

6504 Bridge Point Parkway
Austin, TX 78730-5039
[phone]
Technical support fax: [phone]

[phone]

Branch Offices:

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Switzerland 056/20 51 51, Taiwan 02 377 1200, U.K. 0635 523545

Limited Warranty

The AT-MIO-16 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 A PARTICULAR
PURPOSE
OF

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

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.

. CUSTOMER'S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART

NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER.

. This limitation of the liability of National Instruments will apply regardless of the form of action,

Copyright

Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or
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in part, without the prior written consent of National Instruments Corporation.

Trademarks

LabVIEW®, NI-DAQ®, and RTSI® 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 that are appropriate in the particular situation to prevent
serious injury or death 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.

Contents

About This Manual .......................................................................................................... ix

Organization of This Manual ....................................................................................... ix

Conventions Used in This Manual............................................................................... x

Related Documentation................................................................................................ x

Customer Communication ........................................................................................... x

Chapter 1
Introduction

About the AT-MIO-16................................................................................................. 1-1

What You Need to Get Started .................................................................................... 1-1

Software Programming Choices .................................................................................. 1-2

Unpacking .................................................................................................................... 1-5

Chapter 2
Configuration and Installation

Board Configuration .................................................................................................... 2-1

Hardware Installation................................................................................................... 2-17

....................................................................................................................... 1-1

LabVIEW and LabWindows Application Software ........................................ 1-2

NI-DAQ Driver Software................................................................................. 1-3

Register-Level Programming........................................................................... 1-5

..................................................................................... 2-1

AT Bus Interface.............................................................................................. 2-1

Base I/O Address Selection.................................................................. 2-3

DMA Channel Selection ...................................................................... 2-4

Interrupt Selection................................................................................ 2-5

Analog I/O Configuration ................................................................................ 2-6

Analog Input Configuration................................................................. 2-8

Input Mode............................................................................... 2-9

DIFF Input (Eight Channels, Factory Setting)............. 2-9

RSE Input (16 Channels) ............................................. 2-9

NRSE Input (16 Channels) .......................................... 2-10

Analog Input Polarity and Range............................................. 2-10

Considerations for Selecting Input Ranges.................. 2-11

Analog Output Configuration .............................................................. 2-12

Analog Output Reference......................................................... 2-13

Analog Output Polarity Selection ............................................ 2-14

Analog Output Data Coding .................................................... 2-14

Digital I/O Configuration................................................................................. 2-15

RTSI Bus Clock Selection ............................................................................... 2-17

Chapter 3
Signal Connections

I/O Connector............................................................................................................... 3-1

Signal Descriptions .......................................................................................... 3-3

© National Instruments Corporation v AT-MIO-16 User Manual

........................................................................................................... 3-1

Contents

Analog Input Signal Connections ........................................................ 3-4

Types of Signal Sources....................................................................... 3-5

Floating Signal Sources ........................................................... 3-6

Ground-Referenced Signal Sources......................................... 3-6

Input Configurations ............................................................................ 3-6

Differential Connection Considerations

(DIFF Configuration)............................................................... 3-7

Differential Connections for Grounded Signal Sources .......... 3-8

Differential Connections for Floating Signal Sources ............. 3-8

Single-Ended Connection Considerations ............................... 3-10

Single-Ended Connections for Floating Signal Sources

(RSE Configuration) ................................................................ 3-10

Single-Ended Connections for Grounded Signal Sources

(NRSE Configuration) ............................................................. 3-11

Common-Mode Signal Rejection Considerations.................... 3-11

Analog Output Signal Connections...................................................... 3-12

Digital I/O Signal Connections........................................................................ 3-13

Timing I/O Signals........................................................................................... 3-15

RTSI Bus Signal Connections.......................................................................... 3-15

Power Connections .......................................................................................... 3-16

Timing Connections......................................................................................... 3-16

Data Acquisition Timing Connections................................................. 3-16

General-Purpose Timing Signal Connections...................................... 3-19

Cabling and Field Wiring............................................................................................. 3-25

Field Wiring Considerations ............................................................................ 3-25

Cabling Considerations.................................................................................... 3-26

Chapter 4
Calibration Procedures

Calibration Equipment Requirements.......................................................................... 4-1

Calibration Trimpots.................................................................................................... 4-2

Analog Input Calibration ............................................................................................. 4-3

Board Configuration ........................................................................................ 4-4

Bipolar Input Calibration Procedure................................................................ 4-4

1. Adjust the Amplifier Input Offset................................................... 4-4

2. Adjust the ADC Input Offset .......................................................... 4-4

3. Adjust the Analog Input Gain ......................................................... 4-5

Unipolar Input Calibration Procedure.............................................................. 4-5

1. Adjust the Amplifier Input Offset................................................... 4-5

2. Adjust the ADC Input Offset .......................................................... 4-6

3. Adjust the Analog Input Gain ......................................................... 4-6

Analog Output Calibration........................................................................................... 4-6

Board Configuration ........................................................................................ 4-7

Bipolar Output Calibration Procedure ............................................................. 4-7

1. Adjust the Analog Output Offset .................................................... 4-7

2. Adjust the Analog Output Gain ...................................................... 4-8

Unipolar Output Calibration Procedure ........................................................... 4-8

1. Adjust the Analog Output Offset .................................................... 4-8

2. Adjust the Analog Output Gain ...................................................... 4-9

.................................................................................................... 4-1

AT-MIO-16 User Manual vi © National Instruments Corporation

Contents

Appendix A
Specifications

....................................................................................................................... A-1

Appendix B
Revisions A through C Parts Locator Diagram

.................................................... B-1

Appendix C
Customer Communication

............................................................................................ C-1

Glossary...................................................................................................................... Glossary-1

Index ................................................................................................................................ Index-1

Figures

Figure 1-1. The Relationship between the Programming Environment, NI-DAQ,

and Your Hardware.......................................................................................... 1-4

Figure 2-1. AT-MIO-16 Parts Locator Diagram ................................................................ 2-2

Figure 2-2. Example Base I/O Address Switch Settings .................................................... 2-3

Figure 2-3. Analog Input and Data Acquisition Circuitry Block Diagram ........................ 2-8

Figure 2-4. Analog Output Circuitry Block Diagram......................................................... 2-13

Figure 2-5. Digital I/O Circuitry Block Diagram ............................................................... 2-16

Figure 3-1. AT-MIO-16 I/O Connector Pin Assignments.................................................. 3-2

Figure 3-2. AT-MIO-16 Instrumentation Amplifier........................................................... 3-5

Figure 3-3. Differential Input Connections for Grounded Signal Sources......................... 3-8

Figure 3-4. Differential Input Connections for Floating Signal Sources............................ 3-9

Figure 3-5. Single-Ended Input Connections for Floating Signal Sources......................... 3-10

Figure 3-6. Single-Ended Input Connections for Grounded Signal Sources...................... 3-11

Figure 3-7. Analog Output Connections............................................................................. 3-13

Figure 3-8. Digital I/O Connections ................................................................................... 3-14

Figure 3-9. RTSI Bus Interface Circuitry Block Diagram.................................................. 3-15

Figure 3-10. EXTSTROBE* Signal Timing......................................................................... 3-17

Figure 3-11. EXTCONV* Signal Timing............................................................................. 3-17

Figure 3-12. STARTTRIG* Signal Timing.......................................................................... 3-18

Figure 3-13. STOPTRIG Signal Timing............................................................................... 3-18

Figure 3-14. Timing I/O Circuitry Block Diagram............................................................... 3-19

Figure 3-15. Counter Block Diagram ................................................................................... 3-20

Figure 3-16. Event-Counting Application with External Switch Gating.............................. 3-22

Figure 3-17. Frequency Measurement Application .............................................................. 3-23

Figure 3-18. General-Purpose Timing Signals ..................................................................... 3-24

Figure 4-1. Calibration Trimpot Location Diagram ........................................................... 4-2

Figure B-1. Revisions A through C Parts Locator Diagram ............................................... B-2

© National Instruments Corporation vii AT-MIO-16 User Manual

Contents

Tables

Table 2-1. AT Bus Interface Factory-Default Settings ..................................................... 2-1

Table 2-2. Switch Settings with Corresponding Base I/O Address and

Base I/O Address Space................................................................................... 2-4

Table 2-3. DMA Jumper Settings...................................................................................... 2-5

Table 2-4. Interrupt Jumper Settings................................................................................. 2-5

Table 2-5. Analog I/O Jumper Settings Quick Reference................................................. 2-6

Table 2-6. DIFF Input Configuration (Factory Setting).................................................... 2-9

Table 2-7. RSE Input Configuration ................................................................................. 2-10

Table 2-8. NRSE Input Configuration............................................................................... 2-10

Table 2-9. Configurations for Input Range and Input Polarity ......................................... 2-11

Table 2-10. Actual Range and Measurement Precision Versus Input Range

Selection and Gain ........................................................................................... 2-12

Table 2-11. Internal and External Reference Selection....................................................... 2-14

Table 2-12. Analog Output Polarity and Data Mode Configuration................................... 2-15

Table 2-13. Output Range Selection and Precision............................................................. 2-15

Table 2-14. Configurations for RTSI Bus Clock Selection................................................. 2-17

Table 3-1. Recommended Input Configurations for Ground-Referenced

and Floating Signal Sources............................................................................. 3-6

Table 4-1. Voltage Values for Calculating Offset Error ................................................... 4-3

AT-MIO-16 User Manual viii © National Instruments Corporation

About This Manual

This manual describes the electrical and mechanical aspects of the AT-MIO-16 and contains
information concerning its operation and programming. The AT-MIO-16 is a high-performance
multifunction analog, digital, and timing I/O board, and is a member of the National Instruments
AT Series of expansion boards for the IBM PC AT and compatible computers. The AT-MIO-16
contains a 12-bit ADC with up to 16 analog inputs, two 12-bit DACs with voltage outputs, eight
lines of TTL-compatible digital I/O, and three 16-bit counter/timer channels for timing I/O. If
you need additional analog inputs, you can use the AMUX-64T multiplexer board, which is a
four-to-one multiplexer that can process 64 single-ended inputs. You can cascade up to four
AMUX-64Ts to obtain 256 single-ended inputs.

Organization of This Manual

The AT-MIO-16 User Manual is organized as follows:

• Chapter 1, Introduction, describes the AT-MIO-16; lists the contents of your AT-MIO-16 kit,
the optional software, and optional equipment; and explains how to unpack the AT-MIO-16.

• Chapter 2, Configuration and Installation, describes how to configure the AT-MIO-16
jumpers and how to install the AT-MIO-16 board into the PC.

• Chapter 3, Signal Connections, describes the signal connections to the AT-MIO-16 board,
and cable wiring.

• Chapter 4, Calibration Procedures, discusses the calibration procedures for the AT-MIO-16
analog input and analog output circuitry.

• Appendix A, Specifications, lists the specifications for the AT-MIO-16.

• Appendix B, Revisions A through C Parts Locator Diagram, contains the parts locator
diagram for revisions A through C of the AT-MIO-16 board.

• Appendix C, Customer Communication, contains forms you can use to request help from
National Instruments or to comment on our products.

• The Glossary contains an alphabetical list and description of terms used in this manual,
including acronyms, abbreviations, metric prefixes, mnemonics, and symbols.

• The Index alphabetically lists topics covered in this manual, including the page where you
can find the topic.

© National Instruments Corporation ix AT-MIO-16 User Manual

About This Manual

Conventions Used in This Manual

The following conventions are used in this manual.
bold italic Bold italic text denotes a note, caution, or warning.
italic Italic text denotes emphasis, a cross reference, or an introduction to a key

concept.

NI-DAQ NI-DAQ is used throughout this manual to refer to the NI-DAQ software

for PC compatibles unless otherwise noted.
PC PC refers to the IBM PC AT and compatible computers.
Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and terms are listed in the

Glossary.

Related Documentation

The following document contains information that you may find helpful as you read this manual:

• IBM Personal Computer AT Technical Reference manual
You may also want to consult the following Advanced Micro Devices manual if you plan to

program the Am9513A counter/timer used on the AT-MIO-16:

• Am9513A/Am9513 System Timing Controller technical manual
National Instruments offers a register-level programmer manual at no charge to customers who

are not using National Instruments software:

• AT-MIO-16 Register-Level Programmer Manual

®

If you are using NI-DAQ, LabVIEW, or LabWindows
programmer manual. Using NI-DAQ, LabVIEW, or LabWindows is quicker and easier than and
as flexible as using the low-level programming described in the register-level programmer
manual. Refer to Software Programming Choices in Chapter 1, Introduction, of this manual if
you need more information about your programming options.

If you are not using National Instruments software, you can request the register-level
programmer manual by mailing or faxing the Register-Level Programmer Manual Request Form
at the back of this manual to National Instruments.

, you should not need the register-level

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 C, Customer

Communication, at the end of this manual.

AT-MIO-16 User Manual x © National Instruments Corporation

Chapter 1 Introduction

This chapter describes the AT-MIO-16; lists the contents of your AT-MIO-16 kit; describes the
optional software and optional equipment; and explains how to unpack the AT-MIO-16.

About the AT-MIO-16

Congratulations on your purchase of the National Instruments AT-MIO-16. The AT-MIO-16 is a
high-performance, software-configurable 12-bit DAQ board for laboratory, test and
measurement, and data acquisition and control applications. The board performs high-accuracy
measurements with high-speed settling to 12 bits, noise as low as 0.1 LSBrms, and a typical
DNL of ±0.5 LSB. Because of its FIFOs and dual-channel DMA, the AT-MIO-16 can achieve
high performance, even when used in environments that may have long interrupt latencies such
as Windows.

A common problem with DAQ boards is that you cannot easily synchronize several
measurement functions to a common trigger or timing event. The AT-MIO-16 has the Real­Time System Integration (RTSI) bus to solve this problem. The RTSIbus consists of our custom
RTSI bus interface chip and a ribbon cable to route timing and trigger signals between several
functions on one or DAQ boards in your PC.

The AT-MIO-16 can interface to the Signal Conditioning eXtensions for Instrumentation (SCXI)
system so that you can acquire over 3,000 analog signals from thermocouples, RTDs, strain
gauges, voltage sources, and current sources. You can also acquire or generate digital signals for
communication and control. SCXI is the instrumentation front-end for plug-in DAQ boards.

What You Need to Get Started

Two versions of the AT-MIO-16 are available–one version for each of two gain ranges. The
AT-MIO-16L (L stands for low-level signals) has software-programmable gain settings of 1, 10,
100, and 500 for low-level analog input signals. The AT-MIO-16H (H stands for high-level
signals) has software-programmable gain settings of 1, 2, 4, and 8 for high-level analog input
signals. The AT-MIO-16(L/H)-9 contains an ADC with a 9 µs conversion time. The
AT-MIO-16(L/H)-9 is capable of data acquisition rates of up to 100 kHz.

To set up and use your AT-MIO-16 board, you will need the following:

An AT-MIO-16 board

AT-MIO-16 User Manual

© National Instruments Corporation 1-1 AT-MIO-16 User Manual

Introduction Chapter 1

Either of the following software:
NI-DAQ software for PC compatibles, with manuals

LabVIEW for Windows, LabWindows for DOS, or LabWindows/CVI for Windows,

with manuals

Your computer

Detailed specifications of the AT-MIO-16 are listed in Appendix A, Specifications.

Software Programming Choices

There are four options to choose from when programming your National Instruments plug-in
DAQ and SCXI hardware. You can use LabVIEW, LabWindows, NI-DAQ, or register-level
programming software.

The AT-MIO-16 works with LabVIEW for Windows, LabWindows for DOS, LabWindows/CVI
for Windows, and NI-DAQ for PC compatibles.

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 9800 computers running Microsoft 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 boards, is
included with LabVIEW. The LabVIEW Data Acquisition VI Libraries are functionally
equivalent to the NI-DAQ software.

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 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 boards, is included with
LabWindows for DOS and LabWindows/CVI. The LabWindows Data Acquisition libraries are
functionally equivalent to the NI-DAQ software.

Using LabVIEW or LabWindows software will greatly diminish the development time for your
data acquisition and control application.

AT-MIO-16 User Manual 1-2 © National Instruments Corporation

Chapter 1 Introduction

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.

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 AT-MIO-16 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 event­driven data acquisition applications. An example of a 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 interrupts and DMA controllers. NI-DAQ maintains a
consistent software interface among its different versions so that you can change platforms with
minimal modifications to your code. Figure 1-1 illustrates the relationship between NI-DAQ and
LabVIEW and LabWindows. You can see that the data acquisition parts of LabVIEW and
LabWindows are functionally equivalent to the NI-DAQ software.

© National Instruments Corporation 1-3 AT-MIO-16 User Manual

Introduction Chapter 1

Conventional 

Programming 

Environment 

(PC, Macintosh, or 

Sun SPARCstation)



LabVIEW 

(PC, Macintosh, or 

Sun SPARCstation)

NI-DAQ

Driver Software

LabWindows

(PC or 

Sun SPARCstation)

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, EISA, DAQCard, and

DAQPad Series DAQ hardware

and the SCXI-1200 are 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, Microsoft Visual
C++, and Borland C++ for Windows; and Microsoft Visual C++ for Windows NT. You can use
your AT-MIO-16, 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.

AT-MIO-16 User Manual 1-4 © National Instruments Corporation

Chapter 1 Introduction

Register-Level Programming

The final option for programming any National Instruments DAQ hardware is to write register­level 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, 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, is as flexible as, and can save weeks of
development time.

The AT-MIO-16 User Manual and your software manuals contains complete instructions for
programming your AT-MIO-16 board with NI-DAQ, LabVIEW, or LabWindows. If you are
using NI-DAQ, LabVIEW, or LabWindows to control your board, you should not need the
register-level programmer manual.

The AT-MIO-16 Register-Level Programmer Manual contains low-level programming details,
such as register maps, bit descriptions, and register programming hints, that you will need only
for register-level programming. If you want to obtain the register-level programmer manual,
please fill out the Register-Level Programmer Manual Request Form at the end of this manual
and send it to National Instruments.

Unpacking

Your AT-MIO-16 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 object.

• 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 a damaged board into your computer.

• Never touch the exposed pin of connectors.

© National Instruments Corporation 1-5 AT-MIO-16 User Manual

Chapter 2 Configuration and Installation

This chapter describes how to configure the AT-MIO-16 jumpers and how to install the
AT-MIO-16 board into the PC.

Board Configuration

The AT-MIO-16 contains 13 jumpers and one DIP switch to configure the AT bus interface and
analog I/O settings. The DIP switch is for setting the base I/O address. Two jumpers are
interrupt channel and DMA selectors. The remaining 11 jumpers change the analog input and
analog output circuitry. The parts locator diagram in Figure 2-1 shows the user-configurable
jumpers. Jumpers W1, W4, W6, and W9 configure the analog input circuitry. Jumpers W2, W3,
W7, W8, W10, and W11 configure the analog output circuitry. Jumper W5 selects the clock
signal the Am9513A counter/timer uses and selects the clock pin on the RTSI bus. Jumpers W12
and W13 select the DMA channel and the interrupt level, respectively.

AT Bus Interface

The AT-MIO-16 is configured at the factory to a base I/O address of hex 220, to use DMA
channels 6 and 7, and to use interrupt level 10. These settings, as shown in Table 2-1, are
suitable for most systems. If your system, however, has other hardware at this base I/O address,
DMA channel, or interrupt level, you will need to change these settings on the other hardware or
on the AT-MIO-16 as described in the following pages.

Table 2-1. AT Bus Interface Factory-Default Settings

AT-MIO-16 Board Default Setting Hardware Implementation

Base I/O address

U61

Address space 32 bytes (hex 20)
DMA channel

W12

Interrupt level

W13

Hex 220
Range: hex 220 to hex 23F

DMA 1 = DMA channel 6
DMA 2 = DMA channel 7

Interrupt level 10 selected

A9A8A7A6A5

12345

U61

R7
A7
R6
A6
R5
A5

1

2

DMA

3456791011121415

W13

IRQ

W12

© National Instruments Corporation 2-1 AT-MIO-16 User Manual

Chapter 2 Configuration and Installation

Note: The parts locator diagram shown in Figure 2-1 is for revision D and subsequent

revisions of the AT-MIO-16 board. See Appendix B, Revisions A through C Parts
Locator Diagram, for earlier revisions of the AT-MIO-16 board. The remainder of this
chapter applies to all revisions of the AT-MIO-16 board.

In the configuration illustrations throughout this chapter, the black bars on the jumper diagrams
indicate where to place jumpers. On the switch diagrams, the shaded portion indicates the side of
the switch that is pressed down.

Base I/O Address Selection

The switches at position U61 determine the base I/O address for the AT-MIO-16, as shown in
Figure 2-1. Each switch in U61 corresponds to one of the address lines A9 through A5. Press
the side marked OFF to select a binary value of 1 for the corresponding address bit. Press the
other side of the switch to select a binary value of 0 for the corresponding address bit. Figure 2-2
shows two possible switch settings.

Note: Verify that other equipment installed in your computer does not already occupy the

AT-MIO-16 address space. If any equipment in your computer uses this base I/O
address space, you must change the base I/O address of either the AT-MIO-16 or that
of the other device. If you change the AT-MIO-16 base I/O address, you must make
a corresponding change to any software you use with the AT-MIO-16. For more
information about the I/O address of your PC AT, refer to the technical reference
manual for your computer.

A9A8A7A6A5

12345

U61

This side down for 0
This side down for 1

A9A8A7A6A5

12345

U61

a. Switches Set to Base I/O
Address of Hex 000

This side down for 0
This side down for 1

b. Switches Set to Base I/O Address of Hex
220 (Factory Setting)

Figure 2-2. Example Base I/O Address Switch Settings

To change the base I/O address, remove the plastic cover on U61; press each switch to the
desired position; check each switch to make sure the switch is pressed down all the way; and
replace the plastic cover. Make a note of the new AT-MIO-16 base I/O address on the
configuration form in Appendix C, Customer Communication, to use when configuring the
software you are using with the AT-MIO-16. Table 2-2 lists the possible switch settings, the
corresponding base I/O address, and the base I/O address space for each setting.

© National Instruments Corporation 2-3 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

Table 2-2. Switch Settings with Corresponding Base I/O Address and Base I/O Address Space

Switch Setting Base I/O Address Base I/O Address

A9 A8 A7 A6 A5

0 1 1 0 0 180 180-19F
0 1 1 0 1 1A0 1A0-1BF
0 1 1 1 0 1C0 1C0-1DF
0 1 1 1 1 1E0 1E0-1FF
1 0 0 0 0 200 200-21F
1 0 0 0 1 220 220-23F
1 0 0 1 0 240 240-25F
1 0 0 1 1 260 260-27F
1 0 1 0 0 280 280-29F
1 0 1 0 1 2A0 2A0-2BF
1 0 1 1 0 2C0 2C0-2DF
1 0 1 1 1 2E0 2E0-2FF
1 1 0 0 0 300 300-31F
1 1 0 0 1 320 320-33F
1 1 0 1 0 340 340-35F
1 1 0 1 1 360 360-37F
1 1 1 0 0 380 380-39F
1 1 1 0 1 3A0 3A0-3BF
1 1 1 1 0 3C0 3C0-3DF
1 1 1 1 1 3E0 3E0-3FF

(hex) Space Used (hex)

Note: Base I/O address values hex 000 through 0FF are reserved for

system use. Base I/O address values hex 100 through 3FF are
available on the I/O channel.

DMA Channel Selection

The AT-MIO-16 uses the DMA channel you select with the jumpers on W12 as shown in
Figure 2-1. The AT-MIO-16 is set at the factory to use DMA channels 6 and 7. Verify that
equipment already installed in your computer does not also use these DMA channels. If any
device uses DMA channel 6 or 7, change or disable the DMA channel or channels of either the
AT-MIO-16 or the other device. The AT-MIO-16 hardware supports DMA channels 5, 6, and 7.
Notice that these are the three 16-bit channels on the PC AT I/O channel. The AT-MIO-16 does
not use and cannot be configured to use the 8-bit DMA channels on the PC AT I/O channel.

You must install two jumpers on W12 to select a DMA channel. The DMA Acknowledge lines
(A- prefix is printed on the board) and the DMA Request lines (R- prefix is printed on the board)
that you select must have the same number suffix (5, 6, or 7) for proper operation. When you
enable two DMA channels, the driver software has the option of using dual DMA mode, which
may improve performance in high-rate data acquisition. However, data acquisition can operate
properly with one or both DMA channels disabled. Disabling DMA 2 or disabling both DMA
channels may be necessary if no more DMA channels are available on your system. If two
AT-MIO-16s are installed in the same computer, for instance, you must disable DMA 2 on one
of the boards. The left two columns of W12 are for DMA 1, which is referred to as DMA A in
National Instruments software. The right two columns of W12 are for DMA 2, which is referred

AT-MIO-16 User Manual 2-4 © National Instruments Corporation

Chapter 2 Configuration and Installation

to as DMA B in National Instruments software. Table 2-3 shows the jumper positions for
selecting two, one, or no DMA channels.

Table 2-3. DMA Jumper Settings

Selecting Two DMA

Channels

DMA jumper settings for

DMA channels 6 and 7

Selecting One DMA

Channel

DMA jumper settings for

DMA channel 6 only

Disabling DMA Channels

DMA jumper settings for

disabling DMA transfers

(factory setting)

R7
A7
R6
A6
R5
A5

1 DMA 2

W12

R7
A7
R6
A6
R5
A5

1 DMA 2

W12

R7
A7
R6
A6
R5
A5

1 DMA 2

W12

Interrupt Selection

The AT-MIO-16 board can connect to any one of the 11 interrupt lines of the PC AT I/O
channel. You select the interrupt line with a jumper on one of the double rows of pins located
above the I/O slot edge connector on the AT-MIO-16 (refer to Figure 2-1). To use the
AT-MIO-16 interrupt capability, you must select an interrupt line and place the jumper in the
appropriate position to enable that particular interrupt line, as shown in Table 2-4.

Table 2-4. Interrupt Jumper Settings

Interrupt Jumper Setting IRQ10

(Factory Setting)

3456791011121415

W13

IRQ

Interrupt Jumper Setting for

Disabling Interrupts

3456791011121415

W13

IRQ

The AT-MIO-16 can share interrupt lines with other devices by using a tristate driver to drive its
selected interrupt line. The AT-MIO-16 interrupt lines are IRQ3, IRQ4, IRQ5, IRQ6, IRQ7,
IRQ9, IRQ10, IRQ11, IRQ12, IRQ14, and IRQ15.

Note: D

O NOT use interrupt line 6 or interrupt line 14. The diskette drive controller uses

interrupt line 6. The hard disk controller on most IBM PC ATs and compatible
computers uses interrupt line 14.

© National Instruments Corporation 2-5 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

Analog I/O Configuration

Table 2-5 is a quick reference guide that lists all of the analog I/O jumper configurations for the
AT-MIO-16 with the factory settings noted. If you can configure your board for your application
by using this table, you can skip the in-depth configuration descriptions in the remainder of this
chapter and proceed to Chapter 3, Signal Connections.

Table 2-5. Analog I/O Jumper Settings Quick Reference

Circuitry Configuration Jumper Settings

ADC input mode Differential (DIFF) (factory

setting)

W6

W9

Referenced single-ended
(RSE)

Nonreferenced single-ended
(NRSE)

ADC input polarity

Bipolar ±10 V (factory setting)

and range

W1

W4

Bipolar ±5 V

Unipolar 0 to +10 V

W9

W9

W9

W1

W1

W1

DIFF

SE

SE

DIFF

SE

DIFF

20 V 10 V

ADC Range

20 V 10 V

ADC Range

20 V 10 V

ADC Range

W6

H
F
D
B

W6

H
F
D
B

W6

H
F
D
B

W4

UB

ADC Mode

W4

UB

ADC Mode

W4

UB

ADC Mode

G
E
C
A

G
E
C
A

G
E
C
A

DAC0 reference Internal (factory setting)

W3

External

W3

EXT

INT

DAC0

W3

EXT

INT

DAC0

(continues)

AT-MIO-16 User Manual 2-6 © National Instruments Corporation

Chapter 2 Configuration and Installation

Table 2-5. Analog I/O Jumper Settings Quick Reference (Continued)

Circuitry Configuration Jumper Settings

DAC1 reference Internal (factory setting)

W2

DAC0 output
polarity–digital

External

Bipolar—Two's complement
mode (factory setting)

format

W10 W8

Unipolar—Straight binary
mode

DAC1 output
polarity–digital

Bipolar—Two's complement
mode (factory setting)

format

W11 W7

Unipolar—Straight binary
mode

BU

W8

BU

•

W8

BU

W7

BU

•

W7

DAC0

DAC0

DAC1

DAC1

•

•

W2

DAC1

W2

DAC1

W10

W10

W11

W11

EXT

INT

EXT

INT

BIN

2SC

DAC0

•

BIN

2SC

•

•

2SC

2SC

BIN

•

BIN

DAC0

DAC1

DAC1

Am9513A and RTSI
bus clock selection

W5

AT-MIO-16 clock signal =
10 MHz (factory setting)

AT-MIO-16 clock signal =
RTSI clock signal

AT-MIO-16 and RTSI clock
signals both = 10 MHz

W5

W5

W5

•

•

BRD

RTSI

BRD

•

•

RTSI

BRD

RTSI

NC

BRD

NC

10 MHz

NC

BRD

NC

10 MHz

NC

BRD

•

•

NC

10 MHz

© National Instruments Corporation 2-7 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

Analog Input Configuration

The AT-MIO-16 handles 16 channels of analog input with software-programmable gain and
12-bit A/D conversion. You change the position of jumpers to change the input mode, range,
and polarity. Figure 2-3 shows a block diagram of the analog input and data acquisition
circuitry.

PC AT I/O Channel

/

Data

Sign

S/H

+

4

A/D RD

sion

Exten-

ADC

Ampli-

fier

–

Programmable

Gain Amplifier

/

12

Data

A/D

FIFO

/

A/D

12

Data

10 V/20 V

Selection (W4)

Unipolar/Bipolar

A/D RD

CONVAVAIL

(W1)

Selection

GAIN1

Data

Data

/

6

MUXGAINWR

Mux

Gain

Memory

MA3

MA2

GAIN0

MA1

/

Mux

MA0

4

Counter

/

4

LASTONE

MUXCTRWR

Counter/Timer

MUXCTRCLK

CONVERT

Data

Acquisition

Signals

Timing

Selection

Mux Mode

(W6 & W9)

MUX1EN

MUX0OUT

Mux

ACH0

ACH1

ACH2

MUX0EN

0

ACH3

ACH4

ACH5

ACH6

ACH7

ACH8

AISENSE

MUX1OUT

1

Mux

I/O Connector

ACH9

ACH1 1

ACH10

ACH12

ACH13

ACH14

ACH15

SCANCLK

Start Trigger

Stop Trigger

External Convert

EXTCONV

SCANCLK

STARTTRIG

STOPTRIG

Figure 2-3. Analog Input and Data Acquisition Circuitry Block Diagram

AT-MIO-16 User Manual 2-8 © National Instruments Corporation

Chapter 2 Configuration and Installation

Input Mode
The AT-MIO-16 has three different input modes—differential (DIFF) input, referenced single-

ended (RSE) input, and nonreferenced single-ended (NRSE) input. The single-ended input
configurations use 16 channels. The DIFF input configuration uses eight channels. You may
find it helpful to refer to the Analog Input Signal Connections section in Chapter 3, Signal
Connections, which contains diagrams showing the signal paths for the three configurations.

The multiplexer-mode selection jumpers configure the analog input channels as 16 single-ended
inputs or 8 differential inputs. When single-ended mode is selected, the outputs of the two
multiplexers are tied together and routed to the positive (+) input of the instrumentation
amplifier. The negative (-) input of the instrumentation amplifier is tied to the AT-MIO-16
ground for RSE input or to the analog return of the input signals via the AI SENSE input on the
I/O connector for NRSE input. When DIFF mode is selected, the output of MUX0 is routed to
the positive (+) input of the instrumentation amplifier, and the output of MUX1 is routed to the
negative (-) input of the instrumentation amplifier.

DIFF Input (Eight Channels, Factory Setting).
DIFF input means that each input signal has its own reference, and the difference between each

signal and its reference is measured. The signal and its reference are each assigned an input
channel. With this input configuration, the AT-MIO-16 can monitor eight different analog input
signals. You select the DIFF input configuration by setting jumpers W6 and W9 shown in
Table 2-6.

Table 2-6. DIFF Input Configuration (Factory Setting)

Jumper

Description

Settings

W6

Jumper is placed in standby position or can be discarded.

H
F
D
B

G
E

AISENSE is tied to the instrumentation amplifier output ground point.

C

Channels 0 through 7 are tied to the positive input of the instrumentation

A

amplifier. Channels 8 through 15 are tied to the negative input of the
instrumentation amplifier.

DIFF

W9

SE

The multiplexer is configured to control eight input channels.

•

RSE Input (16 Channels).
RSE input means that all input signals are referenced to a common ground point that is also tied

to the analog input ground of the AT-MIO-16 board. The negative input of the differential input
amplifier is tied to the analog ground. This configuration is useful when measuring floating
signal sources. See the Types of Signal Sources section in Chapter 3, Signal Connections, for
more information. With this input configuration, the AT-MIO-16 can monitor 16 different
analog input signals. You select the RSE input configuration by setting jumpers W6 and W9 as
shown in Table 2-7.

© National Instruments Corporation 2-9 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

Table 2-7. RSE Input Configuration

Jumper

Description

Settings

W6

H
F
D
B

AISENSE is tied to the instrumentation amplifier signal ground.

G

The instrumentation amplifier negative input is tied to the instrumentation

E

amplifier signal ground.

C

The multiplexer outputs are tied together into the positive input of the

A

instrumentation amplifier.

SE

DIFF

W9

The multiplexer is configured to control 16 input channels.

NRSE Input (16 Channels).
NRSE input means that all input signals are referenced to the same common mode voltage, but

that this common mode voltage is allowed to float with respect to the analog ground of the
AT-MIO-16 board. This common mode voltage is subsequently subtracted out by the input
instrumentation amplifier. This configuration is useful when measuring ground-referenced
signal sources. See the Types of Signal Sources section in Chapter 3, Signal Connections, for
more information. With this input configuration, the AT-MIO-16 can measure 16 different
analog input signals. You select the NRSE input configuration by setting jumpers W6 and W9 as
shown in Table 2-8.

Table 2-8. NRSE Input Configuration

Jumper

Description

Settings

W6

H
F
D
B

W9

DIFF

G

AISENSE is tied to the negative input of the instrumentation amplifier.

E

The jumper is placed in standby position or can be discarded.

C

The multiplexer outputs are tied together into the positive input of the

A

instrumentation amplifier.

SE

The multiplexer control is configured to control 16 input channels.

Analog Input Polarity and Range
The AT-MIO-16 has two input polarities—unipolar and bipolar. Unipolar input means that the

input voltage range is between 0 and V
input means that the input voltage range is between -V

where V

ref

is some positive reference voltage. Bipolar

ref

and +V

ref

. The AT-MIO-16 also has

ref

two input ranges—a 10 V input range and a 20 V input range. You can select one of three
possible input polarity and range configurations as shown in Table 2-9.

AT-MIO-16 User Manual 2-10 © National Instruments Corporation

Chapter 2 Configuration and Installation

Table 2-9. Configurations for Input Range and Input Polarity

Input Polarity Jumper

Settings

Bipolar

(factory setting)

W4

UB

ADC Mode

Unipolar

W4

UB

ADC Mode

Input Range

Jumper Settings

-10 to +10 V (20 V range)
(factory setting)

20 V 10 V

W1

ADC Range

-5 to +5 V (10 V range)

20 V 10 V

W1

ADC Range

0 to +10 V (10 V range)

20 V 10 V

W1

ADC Range

Sign-extension circuitry at the ADC FIFO output adds four most significant bits (MSBs), bits 15
through 12, to the 12-bit FIFO output (bits 11 through 0) to produce a 16-bit result. The sign­extension circuitry is software programmable to generate either straight binary numbers or two's
complement numbers. In straight binary mode, bits 15 through 12 are always zero and provide a
range of 0 to 4,095. In two's complement mode, the MSB of the 12-bit ADC result, bit 11, is
inverted and extended to bits 15 through 12, providing a range of -2,048 to +2,047.

Considerations for Selecting Input Ranges.
Input polarity/range selection depends on the expected input range of the incoming signal. A

large input range can accommodate a large signal variation but sacrifices voltage resolution.
Choosing a smaller input range increases voltage resolution but may cause the input signal to go
out of range. For best results, match the input range as closely as possible to the expected range
of the input signal. For example, if the input signal will never become negative (below 0 V), a
unipolar input is best. However, if the signal does become negative, inaccurate readings will
occur.

The AT-MIO-16 software-programmable gain increases its overall flexibility by matching input
signal ranges to those the AT-MIO-16 ADC accommodates. The AT-MIO-16H board has gains
of 1, 2, 4, and 8 and is suited for high-level signals near the range of the ADC. The
AT-MIO-16L board is designed to measure low-level signals and has gains of 1, 10, 100,
and 500. With the proper gain setting, you can use the full resolution of the ADC to measure the
input signal. Table 2-10 shows the overall input range and precision according to the input range

© National Instruments Corporation 2-11 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

configuration and gain used. In single-channel data acquisition applications, the maximum
allowable rate is 100 kHz, or the maximum specified rate of the AT-MIO-16 board.

Multichannel applications may need to slow the acquisition rate due to gain. These numbers are
listed in Table 2-10 as well.

Table 2-10. Actual Range and Measurement Precision

Versus Input Range Selection and Gain

Range

Configuration

0 to +10 V 1 0 to +10 V 2.44 mV 100 kHz

-5 to +5 V 1 -5 to +5 V 2.44 mV 100 kHz

-10 to +10 V 1 -10 to +10 V 4.88 mV 100 kHz

* The value of 1 LSB of the 12-bit ADC, that is, the voltage increment corresponding to a change of 1 count

in the ADC 12-bit count.

Board
Model

-H 2 0 to +5 V 1.22 mV 100 kHz

-L 10 0 to +1 V 244 µV 100 kHz

-H 2 -2.5 to +2.5 V 1.22 mV 100 kHz

-L 10 -0.5 to +0.5 V 244 µV 100 kHz

-H 2 -5 to +5 V 2.44 mV 100 kHz

-L 10 -1 to +1 V 488 µV 100 kHz

Gain Actual Input

Range

4 0 to +2.5 V 610 µV 100 kHz
8 0 to +1.25 V 305 µV 100 kHz

1 0 to +10 V 2.44 mV 100 kHz

100 0 to +0.1 V 24.4 µV 70 kHz
500 0 mV to +20 mV 4.88 µV 20 kHz

4 -1.25 to +1.25 V 610 µV 100 kHz
8 -0.625 to +0.625 V 305 µV 100 kHz

1 -5 to +5 V 2.44 mV 100 kHz

100 -50 mV to +50 mV 24.4 µV 70 kHz
500 -10 mV to +10 mV 4.88 µV 20 kHz

4 -2.5 to +2.5 V 1.22 mV 100 kHz
8 -1.25 to +1.25 V 610 µV 100 kHz

1 -10 to +10 V 4.88 mV 100 kHz

100 -0.1 to +0.1 V 48.8 µV 70 kHz
500 -20 mV to +20 mV 9.76 µV 20 kHz

Precision Maximum

Multichannel

Acquisition Rate

Analog Output Configuration

The AT-MIO-16 provides two channels of 12-bit digital-to-analog (D/A) output. Each analog
output channel provides options such as unipolar or bipolar output and internal or external
reference voltage selection. Figure 2-4 shows a block diagram of the analog output circuitry.

AT-MIO-16 User Manual 2-12 © National Instruments Corporation

Chapter 2 Configuration and Installation

Bipolar/
Unipolar
Selection

(W8)

DAC0WR

DATA
/
12

DAC1WR

PC AT I/O Channel

+10 V

(From

A/D

REF)

REF

DAC1 + op-amps

Bipolar/
Unipolar
Selection

Internal
REF

(W7)

DAC1OUTDAC0 + op-amps

AOGND

DAC0OUT
EXTREF

I/O Connector

(W2)

(W3)

REF
Selection

Figure 2-4. Analog Output Circuitry Block Diagram
Analog Output Reference
You can connect each DAC to the AT-MIO-16 internal reference of 10 V or to the external

reference signal connected to the EXTREF pin on the I/O connector. This signal applied to
EXTREF must be between -10 V and +10 V. Both channels need not be configured the same
way. When you select the external reference jumper setting, the voltage at EXTREF on the I/O
connector is connected to the DAC reference input. When you select the internal reference
jumper setting, the onboard 10 V reference signal is connected to the DAC reference input.

You select the external or internal reference signal for each analog output channel by setting
jumpers W2 and W3 as shown in Table 2-11.

© National Instruments Corporation 2-13 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

Table 2-11. Internal and External Reference Selection

Analog Output Jumper Settings

Channel

Internal (Factory Setting) External

0

1

W3

EXT

INT

DAC0

W3

EXT

INT

DAC1

W2

EXT

INT

DAC0

W2

EXT

INT

DAC1

Analog Output Polarity Selection
You can configure each analog output channel for either unipolar or bipolar output. A unipolar

configuration has a range of 0 to V
of -V

to +V

ref

at the analog output. V

ref

at the analog output. A bipolar configuration has a range

ref

is the voltage reference the DACs use in the analog

ref

output circuitry and can either be the 10 V onboard reference or an externally supplied reference
between -10 V and +10 V. Both channels need not be configured the same way; however, at the
factory both channels are configured for bipolar output.

Analog Output Data Coding.
You must select whether to write to the DAC in straight binary format or two's complement

format. In two's complement mode, data values written to the analog output channel range from

-2,048 to +2,047 decimal (F800 to 07FF hex). In straight binary mode, data values written to the
analog output channel range from 0 to 4,095 decimal (0 to 0FFF hex). Two’s complement
coding is best suited to the bipolar analog output mode, which is the AT-MIO-16 factory setting.
Straight binary coding is usually used for the unipolar analog output configuration.

The analog output polarity and data mode configurations are shown in Table 2-12. Table 2-13
shows the relationship of the output range to the polarity.

AT-MIO-16 User Manual 2-14 © National Instruments Corporation

Chapter 2 Configuration and Installation

Table 2-12. Analog Output Polarity and Data Mode Configuration

Analog
Output

Channel

0 Bipolar

(factory setting)

1 Bipolar

(factory setting)

Polarity Jumper

Settings

BU

W8

DAC0

Unipolar

W8

W7

Unipolar

W7

B

DAC0

BU

DAC1

B

DAC1

Data

Mode

Jumper
Settings

Two’s

2SC

2SC

BIN

DAC0

BIN

DAC0

complement

(factory setting)

U

Straight binary

W10

W10

Two’s

2SC

2SC

BIN

DAC1

BIN

DAC1

complement

(factory setting)

U

Straight binary

W11

W11

Table 2-13. Output Range Selection and Precision

Polarity Output Range Precision

Unipolar 0 - 10 V 2.44 mV
Bipolar -10 - +10 V 4.88 mV

Note: If you are using software such as LabVIEW, LabWindows, or NI-DAQ, you may need

to reconfigure your software to reflect any changes in jumper or switch settings.

Digital I/O Configuration

The AT-MIO-16 provides eight digital I/O lines. These lines are divided into two ports of four
lines each and are located at pins ADIO<3..0> and BDIO<3..0> on the I/O connector. You can
configure each port for input or output through software programming of a register on the
AT-MIO-16 board. Figure 2-5 shows a block diagram of the digital I/O circuitry.

© National Instruments Corporation 2-15 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

ADIO <3..0>

BDIO <3..0>

I/O Connector

DOUT0

/

4

/

4

/

4

/

4

Digital

Output

Register

DOUT1

Digital

Output

Register

A

Digital

Input

Register

B

DATA <3..0>

/

4

DOUT0 ENABLE

DOREGWR

DATA <7..4>

/
4

DOUT1 ENABLE

DATA <7..0>

/

8

DIREGRD

PC AT I/O Channel

EXTSTROBEWR*EXTSTROBE*

Figure 2-5. Digital I/O Circuitry Block Diagram

The Digital Output Register controls the digital I/O lines and the Digital Input Register monitors
them. The Digital Output Register is an 8-bit register that contains the digital output values for
both ports 0 and 1. When port 0 is enabled, bits <3..0> in the Digital Output Register are driven
onto digital output lines ADIO<3..0>. When port 1 is enabled, bits <7..4> in the Digital Output
Register are driven onto digital output lines BDIO<3..0>.

Reading the Digital Input Register returns the state of the digital I/O lines. Digital I/O lines
ADIO<3..0> are connected to bits <3..0> of the Digital Input Register. Digital I/O lines
BDIO<3..0> are connected to bits <7..4> of the Digital Input Register. When a port is enabled,
the Digital Input Register serves as a read-back register, returning the digital output value of the
port. When a port is not enabled, reading the Digital Input Register returns the state of the digital
I/O lines as driven by an external device.

AT-MIO-16 User Manual 2-16 © National Instruments Corporation

Chapter 2 Configuration and Installation

RTSI Bus Clock Selection

When multiple AT Series boards are connected via the RTSI bus, you may want all the boards to
use the same 10 MHz clock. This arrangement is useful for applications that require
counter/timer synchronization between boards. Each AT Series board with a RTSI bus interface
has an onboard 10 MHz oscillator. Thus, one board can drive the RTSI bus clock signal, and the
other boards can receive this signal or disconnect from it.

The configuration for jumper W5 specifies whether a board is to drive the onboard 10 MHz
oscillator onto the RTSI bus, receive the RTSI bus clock, or disconnect from the RTSI bus clock.
This clock source, whether local or RTSI signal, is then divided by 10 and used as the Am9513A
frequency source. The jumper selections are shown in Table 2-14.

Table 2-14. Configurations for RTSI Bus Clock Selection

Local Clock Slave Clock Master Clock

Use the local oscillator as
the board clock (factory
setting)

BRD

BRD

NC

W5

NC

RTSI

10 MHz

Receive the RTSI bus clock
signal

BRD

BRD

NC

W5

NC

RTSI

10 MHz

Drive the RTSI bus clock
and the board clock signal
with the local oscillator

BRD

BRD

NC

W5

NC

RTSI

10 MHz

Hardware Installation

You can install the AT-MIO-16 in any available 16-bit expansion slot (AT style) in your
computer. The AT-MIO-16 does not work if installed in an eight-bit expansion slot (PC style).
After you have changed (if needed), verified, and recorded the switches and jumper settings, you
are ready to install the AT-MIO-16. The following are general installation instructions, but
consult your PC AT user manual or technical reference manual for specific instructions and
warnings.

1. Turn off your computer.

2. Remove the top cover or access port to the I/O channel.

3. Remove the expansion slot cover on the back panel of the computer.

© National Instruments Corporation 2-17 AT-MIO-16 User Manual

Configuration and Installation Chapter 2

4. Write down your hardware configuration settings in the AT-MIO-16 Hardware and Software

Configuration Form in Appendix C at the back of this manual. You will need these settings

when you install and configure your software.

5. Insert the AT-MIO-16 into a 16-bit slot. It may be a tight fit, but do not force the board into

place.

6. Screw the mounting bracket of the AT-MIO-16 to the back panel rail of the computer.

7. Check the installation.

8. Replace the cover.
The AT-MIO-16 board is installed. You are now ready to install and configure your software.
If you are using NI-DAQ, refer to the NI-DAQ Software Reference Manual for PC Compatibles.

The software installation and configuration instructions are in Chapter 1, Introduction to
NI-DAQ. Find the installation and system configuration section for your operating system and
follow the instructions given there.

If you are using LabVIEW, the software installation instructions are in your LabVIEW release
notes. After you have installed LabVIEW, refer to the Configuring LabVIEW section of
Chapter 1 in your LabVIEW user manual for software configuration instructions.

If you are using LabWindows, the software installation instructions are in Part 1, Introduction to
LabWindows, of the Getting Started with LabWindows manual. After you have installed
LabWindows, refer to Chapter 1, Configuring LabWindows, of the LabWindows User Manual
for software configuration instructions.

AT-MIO-16 User Manual 2-18 © National Instruments Corporation

Chapter 3 Signal Connections

This chapter describes the signal connections to the AT-MIO-16 board, and cable wiring.

I/O Connector

Figure 3-1 shows the pin assignments for the AT-MIO-16 I/O connector. This connector is
located on the back panel of the AT-MIO-16 board and is accessible at the rear of the computer
after the board has been properly installed.

Warning: Connections that exceed any of the maximum ratings of input or output signals

on the AT-MIO-16 can damage the AT-MIO-16 board and the PC AT. The
description of each signal in this section includes information about maximum
input ratings. National Instruments is not liable for any damages resulting from
incorrect signal connections.

© National Instruments Corporation 3-1 AT-MIO-16 User Manual

Signal Connections Chapter 3

AIGND

ACH0
ACH1
ACH2
ACH3
ACH4
ACH5
ACH6
ACH7

AISENSE

DAC1OUT

AOGND

ADIO0

ADIO1

ADIO2

ADIO3

DIGGND

+5 V

EXTSTROBE*

STOPTRIG

SOURCE1

OUT1

GATE2

SOURCE5

OUT5

1

2
43
65

87
109
1211
1413
1615
1817
2019
2221
2423
2625
2827
3029

3231
3433

3635
3837
4039
4241
4443
4645
4847
5049

AIGND
ACH8
ACH9
ACH10
ACH11

ACH12
ACH13
ACH14
ACH15
DAC0OUT
EXTREF
DIGGND
BDIO0
BDIO1
BDIO2
BDIO3

+5 V
SCANCLK
STARTRIG*
EXTCONV*

GATE1
SOURCE2

OUT2
GATE5

FOUT

Figure 3-1. AT-MIO-16 I/O Connector Pin Assignments

AT-MIO-16 User Manual 3-2 © National Instruments Corporation

Chapter 3 Signal Connections

Signal Descriptions

Pin Signal Name Reference Description

1, 2 AIGND N/A Analog Input Ground—These pins are the reference point for

single-ended measurements and the bias current return point
for differential measurements.

3–18 ACH<0..15> AIGND Analog Input Channels 0 through 15—In the DIFF mode, the

input is configured for up to 8 channels. In single-ended
mode, the input is configured for up to 16 channels.

19 AISENSE AIGND Analog Input Sense—This pin serves as the reference node

when the board is in NRSE configuration. If desired, this
signal can be programmed to be driven by the board analog
input ground.

20 DAC0OUT AOGND Analog Channel 0 Output—This pin supplies the voltage

output of analog output channel 0.

21 DAC1OUT AOGND Analog Channel 1 Output—This pin supplies the voltage

output of analog output channel 1.

22 EXTREF AOGND External Reference—This is the external reference input for

the analog output circuitry.

23 AOGND N/A Analog Output Ground—The analog output voltages are

referenced to this node.

24, 33 DIGGND N/A Digital Ground—This pin supplies the reference for the digital

signals at the I/O connector as well as the +5 VDC supply.

25, 27,
29, 31

26, 28,
30, 32

34, 35 +5 V DIGGND +5 VDC Source—This pin is fused for up to 1 A of +5 V

36 SCANCLK DIGGND Scan Clock—This pin pulses once for each A/D conversion in

37 EXTSTROBE* DIGGND External Strobe—Writing to the EXTSTROBE* Register

38 STARTTRIG* DIGGND External Trigger—In posttrigger data acquisition sequences, a

39 STOPTRIG DIGGND Stop Trigger—In pretrigger data acquisition, the low-to-high

40 EXTCONV* DIGGND External Convert—A high-to-low edge on EXTCONV* causes

41 SOURCE1 DIGGND SOURCE1—This pin is from the Am9513A Counter 1 signal.
42 GATE1 DIGGND GATE1—This pin is from the Am9513A Counter 1 signal.

ADIO<0..3> DIGGND Digital I/O port A signals.

BDIO<0..3> DIGGND Digital I/O port B signals.

supply.

the scanning modes. The low-to-high edge indicates when the
input signal can be removed from the input or switched to
another signal.

results in a minimum 200 ns low pulse on this pin.

high-to-low edge on STARTTRIG* initiates the sequence. In
pretrigger applications, the high-to-low edge of STARTTRIG*
initiates pretrigger conversions while the STOPTRIG signal
initiates the posttrigger sequence.

edge of STOPTRIG initiates the posttrigger sequence.

an A/D conversion to occur. If EXTGATE* or EXTCONV*
is low, conversions are inhibited.

(continues)

© National Instruments Corporation 3-3 AT-MIO-16 User Manual

Signal Connections Chapter 3

Pin Signal Name Reference Description (Continued)

43 OUT1 DIGGND OUTPUT1—This pin is from the Am9513A Counter 1 signal.
44 SOURCE2 DIGGND SOURCE2—This pin is from the Am9513A Counter 2 signal.
45 GATE2 DIGGND GATE2—This pin is from the Am9513A Counter 2 signal.
46 OUT2 DIGGND OUT2—This pin is from the Am9513A Counter 2 signal.
47 SOURCE5 DIGGND SOURCE5—This pin is from the Am9513A Counter 5 signal.
48 GATE5 DIGGND GATE5—This pin is from the Am9513A Counter 5 signal.
49 OUT5 DIGGND OUT5—This pin is from the Am9513A Counter 5 signal.
50 FOUT DIGGND FOUT—This pin is from the Am9513A FOUT signal.

The signals on the connector can be grouped into analog input signals, analog output signals,
digital I/O signals, digital power connections, or timing I/O signals. Signal connection
guidelines for each of these groups are described in the following sections.

Analog Input Signal Connections

Pins 1 through 19 of the I/O connector are analog input signal pins. Pins 1 and 2 are AIGND
signal pins. AIGND is an analog input common signal that is routed directly to the ground tie
point on the AT-MIO-16. You can use these pins for a general analog power ground tie point to
the AT-MIO-16 if necessary. Pin 19 is the AISENSE pin. In single-ended mode, this pin is
connected internally to the negative input of the AT-MIO-16 instrumentation amplifier. In DIFF
mode, this signal is connected to the reference ground at the output of the instrumentation
amplifier.

Pins 3 through 18 are the ACH<15..0> signal pins. These pins are tied to the 16 analog input
channels of the AT-MIO-16. In single-ended mode, signals connected to ACH<15..0> are routed
to the positive input of the AT-MIO-16 instrumentation amplifier. In DIFF mode, signals
connected to ACH<7..0> are routed to the positive input of the AT-MIO-16 instrumentation
amplifier, and signals connected to ACH<15..8> are routed to the negative input of the
AT-MIO-16 instrumentation amplifier.

The following input ranges and maximum ratings apply to inputs ACH<15..0>:

• Differential input range ±10 V

• Common-mode input range ±7 V with respect to AT-MIO-16 AIGND

• Input range ±12 V with respect to AT-MIO-16 AIGND

• Maximum input voltage rating ±20 V for the AT-MIO-16 board powered off
±35 V for the AT-MIO-16 board powered on

Warning: Exceeding the differential and common-mode input ranges results in distorted

input signals. Exceeding the maximum input voltage rating may damage the
AT-MIO-16 board and the PC AT. National Instruments is not liable for any
damages resulting from incorrect signal connections.

AT-MIO-16 User Manual 3-4 © National Instruments Corporation

Chapter 3 Signal Connections

Connection of analog input signals to the AT-MIO-16 depends on the configuration of the
AT-MIO-16 analog input circuitry and the type of input signal source. The different AT-MIO-16
configurations use the AT-MIO-16 instrumentation amplifier in different ways. Figure 3-2
shows a diagram of the AT-MIO-16 instrumentation amplifier.

Instrumentation

Vin+

+

Amplifier

+

Vin-

-

V

m

Measured

Voltage

-

Vm = [V

+ -Vin-] * Gain

in

Figure 3-2. AT-MIO-16 Instrumentation Amplifier

The AT-MIO-16 instrumentation amplifier applies gain, common-mode voltage rejection, and
high-input impedance to the analog input signals connected to the AT-MIO-16 board. Signals
are routed to the positive and negative inputs of the instrumentation amplifier through input
multiplexers on the AT-MIO-16. The instrumentation amplifier converts two input signals to a
signal that is the difference between the two input signals multiplied by the gain setting of the
amplifier. The amplifier output voltage is referenced to the AT-MIO-16 ground. The
AT-MIO-16 ADC measures this output voltage when it performs A/D conversions.

All signals must be referenced to ground somewhere, either at the source device or at the
AT-MIO-16. If you have a floating source, you must use a ground-referenced input connection
at the AT-MIO-16. If you have a grounded source, you must use a nonreferenced input
connection at the AT-MIO-16.

Types of Signal Sources

When configuring the input mode of the AT-MIO-16 and making signal connections, you must
first determine whether the signal source is floating or ground referenced. These two types of
signals are described in the following sections.

© National Instruments Corporation 3-5 AT-MIO-16 User Manual

Signal Connections Chapter 3

Floating Signal Sources
A floating signal source is one that is not connected in any way to the building ground system

but rather has an isolated ground-reference point. Some examples of floating signal sources are
outputs of transformers, thermocouples, battery-powered devices, optical isolator outputs, and
isolation amplifiers. The ground reference of a floating signal must be tied to the AT-MIO-16
analog input ground to establish a local or onboard reference for the signal. Otherwise, the
measured input signal varies or appears to float. An instrument or device that provides an
isolated output falls into the floating signal source category.

Ground-Referenced Signal Sources
A ground-referenced signal source is one that is connected in some way to the building system

ground and is therefore already connected to a common ground point with respect to the
AT-MIO-16 board, assuming that the PC AT is plugged into the same power system.
Nonisolated outputs of instruments and devices that plug into the building power system fall into
this category.

The difference in ground potential between two instruments connected to the same building
power system is typically between 1 mV and 100 mV, but can be much higher if power
distribution circuits are not properly connected. If grounded signal source is measured
improperly, this difference may show up as an error in the measurement. The following
connection instructions for grounded signal sources should eliminate this ground potential
difference from the measured signal.

Input Configurations

You can configure the AT-MIO-16 for one of three input modes—NRSE, RSE, or DIFF. The
following sections discuss the use of single-ended and differential measurements, and
considerations for measuring both floating and ground-referenced signal sources. Table 3-1
summarizes the recommended input configuration for both types of signal sources.

Table 3-1. Recommended Input Configurations for Ground-Referenced

and Floating Signal Sources

Type of Signal Recommended Input

Configuration

Ground-Referenced

(nonisolated outputs,
plug-in instruments)

DIFF

NRSE

Floating

(batteries, thermocouples,
isolated outputs)

DIFF with bias resistors

RSE

AT-MIO-16 User Manual 3-6 © National Instruments Corporation

Chapter 3 Signal Connections

Differential Connection Considerations (DIFF Configuration)
Differential connections are those in which each AT-MIO-16 analog input signal has its own

reference signal or signal return path. These connections are available when the AT-MIO-16 is
configured in the DIFF mode. Each input signal is tied to the positive input of the
instrumentation amplifier. The reference signal, or return, is tied to the negative input of the
instrumentation amplifier.

When the AT-MIO-16 is configured for DIFF input, each signal uses two of the multiplexer
inputs–one for the signal and one for its reference signal. Therefore, only eight analog input
channels are available when using the DIFF configuration. Use the DIFF input configuration
when any of the following conditions are present:

• Input signals are low level (less than 1 V).

• Leads connecting the signals to the AT-MIO-16 are greater than 15 ft.

• Any of the input signals requires a separate ground-reference point or return signal.

• The signal leads travel through noisy environments.

Differential signal connections reduce picked-up noise, increase common-mode signal and noise
rejection, and cause input signals to float within the common-mode limits of the input
instrumentation amplifier.

© National Instruments Corporation 3-7 AT-MIO-16 User Manual

Signal Connections Chapter 3

Differential Connections for Grounded Signal Sources
Figure 3-3 shows how to connect a ground-referenced signal source to an AT-MIO-16 board

configured for DIFF input. Configuration instructions are included in the Analog Input
Configuration section of Chapter 2, Configuration and Installation.

Ground-

Referenced

Signal

Source

Common

Mode

Noise,

Ground

Potential,

and so on

3
5

+

V

s

-

+

V

cm

-

7

17

4
6

8

18

19

AISENSE

1, 2

AIGND

ACH<0..7>

ACH<8..15>

Input Multiplexers

Instrumentation

+

-

Amplifier

+

V

m

Measured

Voltage

-

I/O Connector

AT-MIO-16 Board in DIFF Configuration

Figure 3-3. Differential Input Connections for Grounded Signal Sources

With this type of connection, the instrumentation amplifier rejects both the common-mode noise
in the signal and the ground-potential difference between the signal source and the AT-MIO-16
ground (shown as V

in Figure 3-3).

cm

Differential Connections for Floating Signal Sources
Figure 3-4 shows how to connect a floating signal source to an AT-MIO-16 board configured for

DIFF input. Configuration instructions are included in the Analog Input Configuration section of
Chapter 2, Configuration and Installation.

AT-MIO-16 User Manual 3-8 © National Instruments Corporation

Chapter 3 Signal Connections

Floating

Signal

Source

Current

Return

Bias

Paths

3
5

100 kΩ

+

V

S

-

7

17

4
6

8

18

1, 2

AIGND

19

AISENSE

ACH<0..7>

ACH<8..15>

Input Multiplexers

Instrumentation

+

-

Amplifier

+

V

m

Measured

Voltage

-

I/O Connector

AT-MIO-16 Board in DIFF Configuration

Figure 3-4. Differential Input Connections for Floating Signal Sources

The 100 kΩ resistors shown in Figure 3-4 create a return path to ground for the bias currents of
the instrumentation amplifier. If there is no return path, the instrumentation amplifier bias
currents charge up stray capacitances, resulting in uncontrollable drift and possible saturation in
the amplifier. Typically, resistors from 10 kΩ to 100 kΩ are used.

A resistor from each input to ground, as shown in Figure 3-4, produces bias current return paths
for an AC-coupled input signal. This solution, although necessary for AC-coupled signals,
lowers the input impedance of the analog input channel. In addition, the input offset current of
the instrumentation amplifier contributes a DC offset voltage at the input. The amplifier has a
maximum input offset current of ±15 nA and a typical offset current drift of ±20 pA/°C.
Multiplied by the 100 kΩ resistor, this current contributes a maximum offset voltage of 1.5 mV
and a typical offset voltage drift of 2 µV/°C at the input. Keep this in mind when you observe
DC offsets with AC-coupled inputs.

If the input signal is DC-coupled, you need only the resistor that connects the negative signal
input to ground. This connection does not lower the input impedance of the analog input
channel.

© National Instruments Corporation 3-9 AT-MIO-16 User Manual

Signal Connections Chapter 3

Single-Ended Connection Considerations
Single-ended connections are those in which all AT-MIO-16 analog input signals are referenced

to one common ground. The input signals are tied to the positive input of the instrumentation
amplifier, and their common ground point is tied to the negative input of the instrumentation
amplifier.

When the AT-MIO-16 is configured for single-ended input (NRSE or RSE), 16 analog input
channels are available. You can use single-ended input connections when the following criteria
are met by all input signals:

• Input signals are high level (greater than 1 V).

• Leads connecting the signals to the AT-MIO-16 are less than 15 ft.

• All input signals share a common reference signal (at the source).

If any of the preceding criteria are not met, using DIFF input configuration is recommended.
You can jumper configure the AT-MIO-16 for two different types of single-ended connections—

RSE configuration and NRSE configuration. The RSE configuration is for floating signal
sources; in this case, the AT-MIO-16 produces the reference ground point for the external signal.
The NRSE configuration is for ground-referenced signal sources; in this case, the external signal
supplies its own reference ground point and the AT-MIO-16 should not supply one.

Single-Ended Connections for Floating Signal Sources (RSE Configuration)
Figure 3-5 shows how to connect a floating signal source to an AT-MIO-16 board configured for

single-ended input. You must configure the AT-MIO-16 analog input circuitry for RSE input to
make these types of connections. Configuration instructions are included in the Analog Input
Configuration section of Chapter 2, Configuration and Installation.

ACH<0..15>

Input Multiplexer

AIGND

Instrumentation

+

-

Amplifier

+

m

Measured

Voltage

-

V

Floating

Signal

Source

+

V

s

-

I/O Connector

3
5

7

18

1, 2
19

AISENSE

AT-MIO-16 Board in RSE Configuration

Figure 3-5. Single-Ended Input Connections for Floating Signal Sources

AT-MIO-16 User Manual 3-10 © National Instruments Corporation

Chapter 3 Signal Connections

Single-Ended Connections for Grounded Signal Sources (NRSE Configuration)
If you are measuring a grounded signal source with a single-ended configuration, you must

configure the AT-MIO-16 in the NRSE input configuration. Connect the signal to the positive
input of the AT-MIO-16 instrumentation amplifier and connect the signal local ground reference
to the negative input of the AT-MIO-16 instrumentation amplifier. Therefore, you must connect
the ground point of the signal to the AISENSE pin. Any potential difference between the
AT-MIO-16 ground and the signal ground appears as a common-mode signal at both the positive
and negative inputs of the instrumentation amplifier; the amplifier rejects this difference. On the
other hand, if the input circuitry of the AT-MIO-16 is referenced to ground, such as in the RSE
configuration, this difference in ground potentials appears as an error in the measured voltage.

Figure 3-6 shows how to connect a grounded signal source to an AT-MIO-16 board in the NRSE
configuration. Configuration instructions are included in the Analog Input Configuration section
of Chapter 2, Configuration and Installation.

ACH<0..15>

Input Multiplexer

AISENSE

AIGND

AT-MIO-16 Board in NRSE Input Configuration

Ground-

Referenced

Signal

Source

Common-

Mode

Noise

and so on

+

V

s

-

+

V

cm

-

I/O Connector

3
5

7

18

19

1, 2

Figure 3-6. Single-Ended Input Connections for Grounded Signal Sources

Common-Mode Signal Rejection Considerations

Instrumentation

+

-

Amplifier

+

m

Measured

Voltage

-

V

Figures 3-3 and 3-6 show connections for signal sources that are already referenced to some
ground point with respect to the AT-MIO-16. In these cases, the instrumentation amplifier can
reject any voltage caused by ground-potential differences between the signal source and the
AT-MIO-16. In addition, with differential input connections, the instrumentation amplifier can
reject common-mode noise pickup in the leads connecting the signal sources to the AT-MIO-16.

© National Instruments Corporation 3-11 AT-MIO-16 User Manual

The common-mode input range of the AT-MIO-16 instrumentation amplifier is defined as the
magnitude of the greatest common-mode signal that can be rejected.

The common-mode input range for the AT-MIO-16 depends on the size of the differential input
signal (V

diff

= V

+

in

- V

-

) and the gain setting of the instrumentation amplifier. The exact

in

formula for the allowed common-mode input range is as follows:

V

* Gain

V

cm-max

= ± (12 V -

diff

2

)

where the maximum value for V

±10 V range V
0 to +10 V range V
±5 V range V

is as follows:

diff

diff-max
diff-max
diff-max

= ±10 V
= 10 V
= ±5 V

For example, for a differential voltage as large as 20 mV and a gain of 500, the largest common­mode voltage that can be rejected is ±7 V. However, if the differential signal is 10 mV with a
gain of 500, a ±9.5 V common-mode voltage can be rejected.

The common-mode voltage is measured with respect to the AT-MIO-16 ground and can be
calculated by the following formula:

V

cm-actual

where V

+

V

=

+

is the signal at the positive input of the instrumentation amplifier and V

in

in

+ V

2

-

in

-

is the

in

signal at the negative input of the instrumentation amplifier.
If the input signal common-mode range exceeds ±7 V with respect to the AT-MIO-16 ground,

you must limit the amount of floating that occurs between the signal ground and the AT-MIO-16
ground.

Analog Output Signal Connections

Pins 20 through 23 of the I/O connector are analog output signal pins.
Pins 20 and 21 are the DAC0OUT and DAC1OUT signal pins. DAC0OUT is the voltage output

signal for analog output channel 0. DAC1OUT is the voltage output signal for analog output
channel 1.

Pin 22, EXTREF, is the external reference input for both analog output channels. You must
individually configure each analog output channel for external reference selection in order for the
signal applied at the external reference input to be used by that channel. Analog output
configuration instructions are included in the Analog Output Configuration section of Chapter 2,
Configuration and Installation.

The following ranges and ratings apply to the EXTREF input:

• Useful input voltage range ±10 V peak with respect to AOGND

• Absolute maximum ratings ±25 V peak with respect to AOGND

© National Instruments Corporation 3-12 AT-MIO-16 User Manual

Chapter 3 Signal Connections

Pin 23, AOGND, is the ground-reference point for both analog output channels and for the
external reference signal.

Figure 3-7 shows how to make analog output connections and the external reference input
connection to the AT-MIO-16 board. If neither channel is configured to use an external
reference signal, do not connect anything to the EXTREF pin.

EXTREF

22

DAC0OUT

External

Reference

Signal

(Optional)

+

V

ref

­Load

+

VOUT0

20

­23

AOGND

Channel 0

-

Load

VOUT1

+

DAC1OUT

21

Channel 1

Analog Output Channels

AT-MIO-16 Board

Figure 3-7. Analog Output Connections

The external reference signal can be either a DC or an AC signal. This reference signal is
multiplied by the DAC code to generate the output voltage. The DACs in the analog output
channels are rated for -82 dB THD with a 1 kHz, 6 Vrms sine wave reference signal and with the
DACs set at their maximum (full-scale) digital value.

Digital I/O Signal Connections

Pins 24 through 32 of the I/O connector are digital I/O signal pins.
Pins 25, 27, 29, and 31 are connected to the digital lines ADIO<3..0> for digital I/O port A. Pins

26, 28, 30, and 32 are connected to the digital lines BDIO<3..0> for digital I/O port B. Pin 24,
DIGGND, is the digital ground pin for both digital I/O ports. You can individually program
ports A and B to be inputs or outputs.

© National Instruments Corporation 3-13 AT-MIO-16 User Manual

Signal Connections Chapter 3

The following specifications and ratings apply to the digital I/O lines.

• Absolute maximum voltage input rating 6.0 V with respect to DIGGND

• Digital input specifications (referenced to DIGGND):
–V

input logic high voltage 2 V min

IH

–VIL input logic low voltage 0.8 V max

–IIH input current load, logic high input voltage 20 µA max

–IIL input current load, logic low input voltage -20 µA max

• Digital output specifications (referenced to DIGGND):
–V

output logic high voltage 2.4 V min

OH

–VOL output logic low voltage 0.5 V max

–IOH output source current, logic high 2.6 mA max

–IOH output sink current, logic low 24 mA max

With these specifications, each digital output line can drive 11 standard TTL loads and over
50 LS TTL loads.

Figure 3-8 depicts signal connections for three typical digital I/O applications.

+5 V

LED

31

+5 V

Switch

TTL Signal

I/O Connector

29
27
25
32
30
28
26

24

DIGGND

Port A
ADIO<3..0>

Port B
BDIO<3..0>

AT-MIO-16 Board

Figure 3-8. Digital I/O Connections

AT-MIO-16 User Manual 3-14 © National Instruments Corporation

Chapter 3 Signal Connections

In Figure 3-8, port A is configured for digital output, and port B is configured for digital input.
Digital input applications include receiving TTL signals and sensing external device states such
as the state of the switch in Figure 3-8. Digital output applications include sending TTL signals
and driving external devices such as the LED shown in Figure 3-8.

Timing I/O Signals

The AT-MIO-16 uses an Am9513A counter/timer for data acquisition timing and for general­purpose timing I/O functions. An onboard oscillator generates the 10-MHz clock.

RTSI Bus Signal Connections

The AT-MIO-16 is interfaced to the National Instrument RTSI bus. The RTSI bus has seven
trigger lines and a system clock line. You can wire any National Instruments AT Series boards
that have a RTSI bus connector together inside the PC AT and share these signals. Figure 3-9 is
a block diagram of the RTSI bus interface circuitry.

OUT2

GATE1

OUT5

STOPTRIG

A2

DRV

A4

DRV

Drivers

Drivers

A2

RCV

A4

RCV

EXTCONV

FOUT

SOURCE5

OUT1

STARTTRIG

RTSISEL

Internal

Data Bus

MYCLK

A0
A1
A2
A3
A4
A5
A6

/SEL
DATA

RTSI

Switch

W5

B0
B1
B2
B3
B4
B5
B6

10 MHz
Oscillator

Trigger

RTSICLK

/

7

RTSI Bus Connector

Figure 3-9. RTSI Bus Interface Circuitry Block Diagram

© National Instruments Corporation 3-15 AT-MIO-16 User Manual

Signal Connections Chapter 3

The RTSI switch is a National Instruments custom integrated circuit that acts as a 7x7 crossbar
switch. Pins B<6..0> are connected to the seven RTSI bus trigger lines. Pins A<6..0> are
connected to seven signals on the board. The RTSI switch can drive any of the signals at pins
A<6..0> onto any one or more of the seven RTSI bus trigger lines and can drive any of the seven
trigger line signals onto any one or more of the pins A<6..0>. This signal trigger produces a
completely flexible signal interconnection scheme for any AT Series board sharing the RTSI bus.
You program the RTSI switch via its select and data inputs.

On the AT-MIO-16 board, nine signals are connected to pins A<6..0> of the RTSI switch with
the aid of additional drivers. The signals GATE1, OUT1, OUT2, OUT5, FOUT, and
STOPTRIG are shared with the AT-MIO-16 I/O connector and Am9513A counter/timer. The
signal SOURCE5 is connected to the Am9513A SOURCE5 pin. The I/O connector and the data
acquisition timing circuitry share the EXTCONV* and STARTTRIG* signals. Through these
onboard interconnections, you can control the AT-MIO-16 general-purpose and data acquisition
timing over the RTSI bus as well as externally, and use the AT-MIO-16 and the I/O connector to
supply timing signals to other AT boards connected to the RTSI bus.

Power Connections

Pins 34 and 35 of the I/O connector supply +5 V from the PC AT power supply. These pins are
referenced to DIGGND and you can use them to power the external digital circuitry.

• Power rating: 0.5 A at +5 V ± 10%

Warning: These +5 V power pins should

NOT be directly connected to analog or digital

ground or to any other voltage source on the AT-MIO-16 or any other device.
Doing so can damage the AT-MIO-16 and the PC AT. National Instruments is

NOT liable for damages resulting from such a connection.

Timing Connections

Pins 36 through 50 of the I/O connector are connections for timing I/O signals. Pins 36 through
40 carry signals used for data acquisition timing. These signals are explained in the next section,
Data Acquisition Timing Connections. Pins 41 through 50 carry general-purpose timing signals
produced by the onboard Am9513A counter/timer. These signals are explained in the General-
Purpose Timing Signal Connections section later in this chapter.

Data Acquisition Timing Connections

The data acquisition timing signals are SCANCLK, EXTSTROBE*, STARTTRIG*,
STOPTRIG, and EXTCONV*.

SCANCLK is an output signal that generates a high-to-low edge whenever an A/D conversion
begins. SCANCLK pulses only when scanning is enabled on the AT-MIO-16. SCANCLK is
normally high and pulses low for approximately 1 µs after the A/D conversion begins. The low­to-high edge signals that the input signal has been acquired. You can use this signal to clock
external analog input multiplexers. One LS TTL gate drives the SCANCLK signal.

AT-MIO-16 User Manual 3-16 © National Instruments Corporation

Chapter 3 Signal Connections

A low pulse is generated on the EXTSTROBE* pin when the External Strobe Register is
accessed (see the REG_Level_Write function in the NI-DAQ Function Reference Manual for

PC Compatibles or the External Strobe Register description in Chapter 2, Register Maps and
Descriptions, of the AT-MIO-16 Register-Level Programmer Manual). Figure 3-10 shows the

timing for the EXTSTROBE* signal.

t

w

V

OH

V

OL

t

w

100-500 ns

Figure 3-10. EXTSTROBE* Signal Timing

The pulse is typically between 100 ns and 500 ns in width. An external device can use the
EXTSTROBE* signal to latch signals or trigger events. The EXTSTROBE* signal is an
LS TTL signal.

The EXTCONV* pin can externally trigger A/D conversions. Applying an active low pulse to
the EXTCONV* signal initiates an A/D conversion. The low-to-high edge of the applied pulse
initiates the A/D conversion. Figure 3-11 shows the timing requirements for the EXTCONV*
signal.

t

w

V

IH

V

IL

t

w

A/D conversion starts within

250 ns from this point

t

w

50 ns minimum

Figure 3-11. EXTCONV* Signal Timing

The minimum allowed pulse width is 50 ns. An A/D conversion starts within 250 ns of the low­to-high edge. There is no maximum pulse-width limitation. EXTCONV* should be high for at
least 50 ns before going low. The EXTCONV* signal is one LS TTL load and is pulled up to
+5 V through a 4.7 kΩ resistor.

Note: The output of the Am9513A counter/timer counter 3 also drives EXTCONV*. This

counter is also referred to as the sample-interval counter. You must disable the output
of counter 3 to a high-impedance state if pulses applied to the EXTCONV* pin are to
control A/D conversions. If you use counter 3 to control A/D conversions, you can
monitor its output signal at the EXTCONV* pin.

© National Instruments Corporation 3-17 AT-MIO-16 User Manual

Signal Connections Chapter 3

An external trigger applied to the STARTTRIG* pin can initiate any data acquisition sequence
that the onboard sample-interval and sample counters control. If the EXTCONV* signal
generates conversions, STARTTRIG* does not affect the acquisition timing. After the two
counters are initialized and armed, applying a falling edge to the STARTTRIG* pin starts the
counters, thereby initiating a data acquisition sequence.

The high-to-low edge of the applied pulse initiates the data acquisition operation. Figure 3-12
shows the timing requirements for the STARTTRIG* signal.

t

w

V

IH

V

IL

t

w

First A/D conversion starts within
1 sample interval from this point

t

w

50 ns minimum

Figure 3-12. STARTTRIG* Signal Timing

The minimum allowed pulse width is 50 ns. The first A/D conversion starts within one sample
interval from the high-to-low edge. Counter 3 controls the sample interval.

There is no maximum pulse-width limitation; however, STARTTRIG* should be high for at least
50 ns before going low. The STARTTRIG* signal is one LS TTL load and is pulled up to +5 V
through a 4.7 kΩ resistor.

The STOPTRIG pin is used during AT-MIO-16 pretriggered data acquisition operations. In
pretriggered mode, data is acquired but no sample counting occurs until a rising edge is applied
to the STOPTRIG pin. This causes the sample counter to start counting conversions. The
acquisition completes when the sample counter decrements to zero. This mode acquires data
both before and after a hardware trigger is received. Figure 3-13 shows the timing requirements
for the STOPTRIG signal. The STOPTRIG signal is one LS TTL load and is pulled up to +5 V
through a 4.7 kΩ resistor.

V

STOPTRIG

IH

V

IL

t

w

t

w

t

50 ns minimum

w

First sample counting occurs within
1 sample interval from this point

Figure 3-13. STOPTRIG Signal Timing

AT-MIO-16 User Manual 3-18 © National Instruments Corporation

Chapter 3 Signal Connections

General-Purpose Timing Signal Connections

The general-purpose timing signals include the GATE, SOURCE, and OUT signals for the
Am9513A counters 1, 2, and 5, and the FOUT signal that the Am9513A generates. You can use
the Am9513A counter/timer counters 1, 2, and 5 for general-purpose applications such as pulse
and square wave generation, event counting, and pulse-width, time-lapse, and frequency
measurements. For these applications, you can directly apply SOURCE and GATE signals to the
counters from the I/O connector and program the counters for various operations. Figure 3-14
shows a block diagram of the timing I/O circuitry.

FOUT

GATE2

SOURCE2

OUT2

GATE1

SOURCE1

OUT1

GATE5

SOURCE5

OUT5

STOPTRIG

I/O Connector

Flip

Flop

Figure 3-14. Timing I/O Circuitry Block Diagram

Am9513A

Channel
Counter/

GATE4

GATE4

5

Timer

SOURCE4
SOURCE3

OUT1
OUT3
OUT4
OUT5

GATE3

1 MHz CLK

Acquisition

Data

Timing

10

÷

/
16

/
2

MYCLK

(10 MHz)

DATA<15..0>

Am9513 RD/WR

RTSI Bus

PC AT I/O Channel

CONVERT
SCANCLK
MUXCTRCLK

The Am9513A contains five independent 16-bit counter/timers, a 4-bit frequency output channel,
and five internally generated timebases. You can program the five counter/timers to operate in
several useful timing modes.

The Am9513A clock input is one-tenth the MYCLK frequency selected by the W5 jumpers. The
factory-default setting for MYCLK is 10 MHz, which generates a 1-MHz clock input to the
Am9513A. The Am9513A uses this clock input to generate five internal timebases. The
counter/timers and the frequency output channel can use these timebases as clocks. When
MYCLK is 10 MHz, the five internal timebases normally used for AT-MIO-16 timing functions
are 1 MHz, 100 kHz, 10 kHz, 1 kHz, and 100 Hz.

© National Instruments Corporation 3-19 AT-MIO-16 User Manual

Signal Connections Chapter 3

Note: For detailed programming information, consult the AMD Am9513A Data Sheet

in the AT-MIO-16 Register-Level Programmer Manual. For detailed application
information, consult the Am9513A/Am9513A System Timing Controller technical
manual published by Advanced Micro Devices, Inc.

Figure 3-15 is a diagram of the 16-bit counters in the Am9513A.

SOURCE

Counter

GATE

OUT

Figure 3-15. Counter Block Diagram

Each counter has a SOURCE input pin, a GATE input pin, and an output pin labeled OUT. The
Am9513A counters are numbered 1 through 5, and their GATE, SOURCE, and OUT pins are
labeled GATE N, SOURCE N, and OUT N, where N is the counter number.

For counting operations, you can program the counters to use any of the five internal timebases,
any of the five GATE and five SOURCE inputs to the Am9513A, and the output of the previous
counter (counter 4 uses counter 3 output, and so on). You can configure a counter to count either
falling or rising edges of the selected input.

With the counter GATE input, you can gate counter operation. When you have configured a
counter for an operation through software, a signal at the GATE input can start and stop counter
operation. The Am9513A has five gating modes—no gating, level gating active high, level
gating active low, low-to-high edge gating, and high-to-low edge gating. A counter can also be
active high level gated by a signal at GATE N+1 and GATE N-1, where N is the counter number.

The counter generates timing signals at its OUT output pin. You can also set the OUT output pin
to a high-impedance state or a grounded-output state. The counters generate two types of output
signals during counter operation—terminal-count pulse output and terminal-count toggle output.
Terminal count is often referred to as TC. A counter reaches TC when it counts up or down and
rolls over. In many counter applications, the counter reloads from an internal register when it
reaches TC. In TC pulse output mode, the counter generates a pulse during the cycle that it
reaches TC and reloads. In TC toggle output mode, the counter output changes state after it
reaches TC and reloads. In addition, you can configure the counters for positive logic output or
negative (inverted) logic output for a total of four possible output signals generated for one
timing mode.

AT-MIO-16 User Manual 3-20 © National Instruments Corporation

Chapter 3 Signal Connections

The SOURCE, GATE, and OUT pins for counters 1, 2, and 5 of the onboard Am9513A are
located on the AT-MIO-16 I/O connector. A rising-edge signal on the STOPTRIG pin of the I/O
connector sets the flip-flop output signal connected to the GATE4 input of the Am9513A and
can be used as an additional gate input. The flip-flop output connected to GATE4 is cleared
when the sample counter reaches TC, when an overflow or overrun occurs, or when the A/D
Clear Register is written to.

The Am9513A SOURCE5 pin is connected to the AT-MIO-16 RTSI switch, which means that
you can use a signal from the RTSI trigger bus as a counting source for the Am9513A counters.

You can use the Am9513A OUT2 pin in several different ways. If you configure the board for
the later update mode, an active low pulse on OUT2 updates the analog output on the two DACs.
You can also use OUT2 to trigger interrupt requests. If counter interrupts are enabled, an
interrupt occurs when a rising-edge signal is detected on OUT2. You can use this interrupt to
update the DACs or to interrupt on an external signal connected to OUT2 through the I/O
connector.

Counters 3 and 4 of the Am9513A are dedicated to data acquisition timing and therefore are not
made available for general-purpose timing applications. Signals generated at OUT3 and OUT4
are passed to the data acquisition timing circuitry. The data acquisition timing circuitry controls
GATE3.

Counter 5 is sometimes used by the data acquisition timing circuitry and concatenated with
counter 4 to form a 32-bit sample counter. The SCANCLK signal is connected to the SOURCE3
input of the Am9513A, and OUT1 is sent to the data acquisition timing circuitry. Thus,
counter 1 divides the SCANCLK signal for sequencing the channel-gain memory.

The data acquisition timing circuitry sometimes uses counter 2 to assign a time interval to each
cycle through the scan sequence programmed in the mux-gain memory. This mode is called
interval channel scanning.

The Am9513A 4-bit programmable frequency output channel is provided at the I/O connector
FOUT pin. You can select any of the five internal timebases and any of the counter SOURCE or
GATE inputs as the frequency output source. The frequency output channel divides the selected
source by its 4-bit programmed value and sends the divided down signal at the FOUT pin.

You can produce pulses and square waves at the I/O connector by programming counter 1, 2,
or 5 to generate a pulse signal at its OUT output pin or to toggle the OUT signal each time the
counter reaches the terminal count.

For event counting, program one of the counters to count rising or falling edges applied to any of
the Am9513A SOURCE inputs. You can then read the counter value to determine the number of
edges that have occurred. Counter operation can be gated on and off during event counting.

© National Instruments Corporation 3-21 AT-MIO-16 User Manual

Signal Connections Chapter 3

Figure 3-16 shows connections for a typical event-counting operation in which a switch gates the
counter on and off.

+5 V

4.7 kΩ

SOURCE

OUT

GATE

Switch

Signal

Source

I/O Connector

33

DIGGND

AT-MIO-16 Board

Counter

Figure 3-16. Event-Counting Application with External Switch Gating

To perform pulse-width measurement, program a counter to be level gated. Apply the pulse to
be measured to the counter GATE input. Program the counter to count while the signal at the
GATE input is either high or low. If the counter is programmed to count an internal timebase,
the pulse width is equal to the counter value multiplied by the timebase period.

For time-lapse measurement, program a counter to be edge gated. Apply an edge to the counter
GATE input to start the counter. You can program the counter to start counting after receiving
either a high-to-low edge or a low-to-high edge. If the counter is programmed to count an
internal timebase, the time lapse since receiving the edge is equal to the counter value multiplied
by the timebase period.

To measure frequency, program a counter to be level gated and to count the rising or falling
edges of a signal applied to a SOURCE input. The gate signal applied to the counter GATE
input is of some known duration. In this case, program the counter to count either rising or
falling edges at the SOURCE input while the gate is applied. The frequency of the input signal is
equal to the count value divided by the known gate period. Figure 3-17 shows the connections
for a frequency measurement application. You could also use a second counter to generate the
gate signal in this application.

AT-MIO-16 User Manual 3-22 © National Instruments Corporation

Chapter 3 Signal Connections

+5 V

4.7 kΩ

SOURCE

OUT

GATE

Signal

Source

I/O Connector

Gate

Source

33

Counter

DIGGND

AT-MIO-16 Board

Figure 3-17. Frequency Measurement Application

You can concatenate two or more counters by tying the OUT signal from one counter to the
SOURCE signal of another counter. You can then treat the counters as one 32-bit or 48-bit
counter for most counting applications.

The GATE, SOURCE, and OUT signals for counters 1, 2, and 5, and the FOUT output signal are
tied directly from the Am9513A input and output pins to the I/O connector. In addition, the
GATE, SOURCE, and OUT1 pins are pulled up to +5 V through a 4.7 kΩ resistor.

The following input and output ratings and timing specifications apply to the Am9513A signals:

• Absolute maximum voltage input rating -0.5 V to +7.0 V with respect to DIGGND

• Am9513A digital input specifications (referenced to DIGGND):
–V

input logic high voltage 2.2 V min

IH

–VIL input logic low voltage 0.8 V max
– Input load current ±10 µA max

© National Instruments Corporation 3-23 AT-MIO-16 User Manual

Signal Connections Chapter 3

• Am9513A digital output specifications (referenced to DIGGND):
–V

output logic high voltage 2.4 V min

OH

–VOL output logic low voltage 0.4 V max

–IOH output source current, at V

–IOL output sink current, at V

OL

OH

200 µA max

3.2 mA max

– Output current, high-impedance state ±25 µA max

Figure 3-18 shows the timing requirements for the GATE and SOURCE input signals and the
timing specifications for the OUT output signals of the Am9513A.

SOURCE

GATE

t

sc

V

IH

V

IL

t

gsu

V

IH

V

IL

t

gw

t

sp

t

gh

t

sp

t

out

70 ns minimum

100 ns minimum

10 ns minimum
145 ns minimum
300 ns maximum

OUT

V

OH

V

OL

t 145 ns minimum

sc

t

sp

t

gsu

t

gh

t

gw

t

out

Figure 3-18. General-Purpose Timing Signals

The GATE and OUT signal transitions in Figure 3-18 are referenced to the rising edge of the
SOURCE signal. This timing diagram assumes that the counters are programmed to count rising
edges. The same timing diagram, with the source signal inverted and referenced to the falling
edge of the source signal, applies to the case in which the counter is programmed to count falling
edges.

AT-MIO-16 User Manual 3-24 © National Instruments Corporation

Chapter 3 Signal Connections

Any of the Am9513A counter/timers and the Am9513A frequency division output FOUT can use
the signal applied at a SOURCE input as a clock source. The signal applied to a SOURCE input
must not exceed a frequency of 6 MHz for proper operation of the Am9513A. You can
individually program the Am9513A counters to count rising or falling edges of signals applied at
any of the Am9513A SOURCE or GATE input pins.

In addition to the signals applied to the SOURCE and GATE inputs, the Am9513A generates
five internal timebase clocks from the clock signal supplied by the AT-MIO-16. This clock
signal is selected by the W5 jumper and then divided by 10. The factory default value is 1 MHz
into the Am9513A (10 MHz clock signal on the AT-MIO-16). You can use the five internal
timebase clocks as counting sources, and these clocks have a maximum skew of 75 ns between
them. The SOURCE signal shown in Figure 3-18 represents any of the signals applied at the
SOURCE inputs, GATE inputs, or internal timebase clocks.

Specifications for signals at the GATE input are referenced to the signal at the SOURCE input or
one of the Am9513A internally generated signals. Figure 3-18 shows the GATE signal
referenced to the rising edge of a source signal. The gate must be valid (either high or low) at
least 100 ns before the rising or falling edge of a source signal for the gate to take effect at that
source edge as shown by t

at least 10 ns after the rising or falling edge of a source signal for the gate to take effect at that
source edge. The gate high or low period must be at least 145 ns in duration. If you use an
internal timebase clock, the gate signal cannot be synchronized with the clock. In this case, gates
applied close to a source edge take effect either on that source edge or on the next one. This
arrangement creates an uncertainty of one source clock period with respect to unsynchronized
gating sources.

and tgh in Figure 3-18. Similarly, the gate signal must be held for

gsu

Signals generated at the OUT output are referenced to the signal at the SOURCE input or to one
of the Am9513A internally generated clock signals. Figure 3-18 shows the OUT signal
referenced to the rising edge of a source signal. Any OUT signal state changes occur within
300 ns after the source signal rising or falling edge.

Cabling and Field Wiring

This section describes cabling and field wiring guidelines for the AT-MIO-16 board.

Field Wiring Considerations

Environmental noise can seriously affect the accuracy of measurements made with the
AT-MIO-16 if you do not make proper considerations when running signal wires between signal
sources and the AT-MIO-16 board. The following recommendations mainly apply to analog
input signal routing to the AT-MIO-16 board, although they are applicable for signal routing in
general.

© National Instruments Corporation 3-25 AT-MIO-16 User Manual

Signal Connections Chapter 3

You can minimize noise pickup and maximize measurement accuracy by doing the following
things:

• Use individually shielded, twisted-pair wires to connect analog input signals to the
AT-MIO-16. With this type of wire, the signals attached to the CH+ and CH- inputs are
twisted together and then covered with a shield. This shield is then connected at only one
point to the signal source ground. This kind of connection is required for signals traveling
through areas with large magnetic fields or high electromagnetic interference.

• Use differential analog input connections to reject common-mode noise.

The following recommendations apply for all signal connections to the AT-MIO-16:

• Physically separate the AT-MIO-16 signal lines from high-current or high-voltage lines.
These lines can induce currents in or voltages on the AT-MIO-16 signal lines if they run in
parallel paths at a close distance. To reduce the magnetic coupling between lines, separate
the lines by a reasonable distance if they run in parallel, or run the lines at right angles to
each other.

• Do not run the AT-MIO-16 signal lines through conduits that also contain power lines.

• To protect the AT-MIO-16 signal lines from magnetic fields caused by electric motors,
welding equipment, breakers, or transformers, run the AT-MIO-16 signal lines through
special metal conduits.

Cabling Considerations

National Instruments has a cable termination accessory, the CB-50, for use with the AT-MIO-16
board. This kit includes a terminated, 50-conductor flat ribbon cable and a connector block.
You can attach signal input and output wires to screw terminals on the connector block and
thereby connect to the AT-MIO-16 I/O connector.

The CB-50 is useful for prototyping an application or in situations where AT-MIO-16
interconnections are frequently changed. When you develop a final field wiring scheme,
however, you may want to develop your own cable. This section contains information and
guidelines for designing custom cables.

The AT-MIO-16 I/O connector is a 50-pin male ribbon-cable header. The manufacturer part
numbers for this header that National Instruments uses are as follows:

• Electronic Products Division/3M (part number 3596-5002)

• T&B/Ansley Corporation (part number 609-5007)

AT-MIO-16 User Manual 3-26 © National Instruments Corporation

Chapter 3 Signal Connections

The mating connector for the AT-MIO-16 is a 50-position polarized, ribbon-socket connector
with strain relief. National Instruments uses a polarized, keyed connector to prevent inadvertent
upside-down connection to the AT-MIO-16. 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)

The following are standard 50-conductor, 28 AWG, stranded ribbon cables that work with these
connectors:

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

• T&B/Ansley Corporation (part number 171-50)

In making your own cabling, you may decide to shield your cables. The following guidelines
may help:

• For the analog input signals, shielded twisted-pair wires for each analog input pair yield the
best results, assuming that you use differential inputs. Tie the shield for each signal pair to
the ground reference at the source.

• Route the analog lines, pins 1 through 23, separately from the digital lines, pins 24
through 50.

• When using a cable shield, use separate shields for the analog and digital halves of the cable.
Failure to do so will result in noise from switching digital signals coupling into the analog
signals.

© National Instruments Corporation 3-27 AT-MIO-16 User Manual

Chapter 4 Calibration Procedures

This chapter discusses the calibration procedures for the AT-MIO-16 analog input and analog
output circuitry.

The AT-MIO-16 is calibrated at the factory before shipment. To maintain the 12-bit accuracy of
the AT-MIO-16 analog input and analog output circuitry, check your board’s analog input with a
precise voltage source. If the board is out of calibration, then calibrate it. Otherwise, the board
does not need to be calibrated.

The AT-MIO-16 is factory calibrated in its factory-default configuration:

• DIFF analog input mode

• -10 to +10 V analog input range (bipolar)

• -10 to +10 V analog output range (bipolar with internal reference selected)

Whenever you change your board configuration, recalibrate your AT-MIO-16 board.

Calibration Equipment Requirements

For best measurement results, the AT-MIO-16 needs to be calibrated so that its measurement
accuracy is within ±0.012% of its input range (±
equipment you use to calibrate the AT-MIO-16 should be 10 times as accurate, that is, have
±0.001% rated accuracy. Practically speaking, calibration equipment with four times the
accuracy of the item under calibration is generally considered acceptable. Four times the
accuracy of the AT-MIO-16 is 0.003%. You need the following equipment to calibrate the
AT-MIO-16 board:

• For analog input calibration, you need a precision variable DC voltage source (usually a
calibrator) with these features:

– Accuracy ±0.001% standard

±0.003% sufficient
– Range Greater than ±10 V
– Resolution 100 µV in ±10 V range (5

• For analog output calibration, you need a voltmeter with these features:

– Accuracy ±0.001% standard

±0.003% sufficient
– Range Greater than ±10 V
– Resolution 100 µV in ±10 V range (5

1

/2 LSB). According to standard practice, the

1

/2 digits)

1

/2 digits)

© National Instruments Corporation 4-1 AT-MIO-16 User Manual

Chapter 4 Calibration Procedures

• R7—Offset trim, analog output channel 0

• R3—Offset trim, analog output channel 1

Analog Input Calibration

To null error sources that compromise the quality of measurements, you must calibrate the
analog input circuitry by adjusting the following potential sources of error:

• Offset error at the input of the instrumentation amplifier

• Offset error at the input of the ADC

• Gain error of analog input circuitry
Offsets at the input to the instrumentation amplifier contribute gain-dependent offset error to the

analog input circuitry. This offset is multiplied by the gain of the instrumentation amplifier. To
calibrate this offset, you must ground the analog input, read it at two different gain settings, and
adjust a trimpot until the readings match at the two different gain settings.

Offset error at the input of the ADC is the total of the voltage offsets contributed by the circuitry
from the output of the instrumentation amplifier to the ADC input, including the offsets of the
ADC itself. Offset errors appear as a voltage added to the input voltage being measured. To
calibrate this offset, you must apply V

trimpot until the ADC returns readings that flicker between its most negative count and the most
negative count plus one. The voltages corresponding to V

1

+

/2 LSB to the analog input circuitry and adjust a

-fs

and 1 LSB are given in Table 4-1.

-fs

All the stages up to and including the input of the ADC contribute to the gain error of the analog
input circuitry. With the instrumentation amplifier set to a gain of 1, the gain of analog input
circuitry is ideally 1. The gain error is the deviation of the gain from 1 and appears as a
multiplication of the input voltage being measured. To calibrate this offset, you must apply
V

- 3/2 LSB to the analog input circuitry and adjust a potentiometer until the ADC returns

+fs

readings that flicker between its most positive count and the most positive count minus 1. The
voltages corresponding to V

The voltages corresponding to V
V

- 1, which is the most positive voltage the ADC can read, and 1 LSB, which is the voltage

+fs

and 1 LSB are given in Table 4-1.

+fs

, which is the most negative voltage that the ADC can read,

-fs

corresponding to one count of the ADC, depend on the input range selected. The value of these
voltages for each input range is given in Table 4-1.

Table 4-1. Voltage Values for Calculating Offset Error

Input Range V

-fs

V

- 1 1 LSB

+fs

1

/2 LSB

-10 to +10 V -10 V +9.99512 V 4.88 mV 2.44 mV

-5 to +5 V -5 V +4.99756 V 2.44 mV 1.22 mV
0 to 10 V 0 V +9.99756 V 2.44 mV 1.22 mV

© National Instruments Corporation 4-3 AT-MIO-16 User Manual

Calibration Procedures Chapter 4

Board Configuration

The calibration procedure differs depending on the input ranges and input configuration modes
you select. Two analog input calibration procedures are described in the following sections–one
for the two bipolar input configurations (-10 to +10 V and -5 to +5 V), and one for the unipolar
input configuration (0 to +10 V). These calibration procedures assume that your AT-MIO-16 is
configured for DIFF input. If necessary, reconfigure your board for DIFF input before using the
following calibration procedures.

To calibrate your board with a nondifferential input setting, the procedure is similar to the
procedures in this manual with one exception–the following procedures apply the input
calibration voltages across the positive and negative inputs for DIFF channel 0. For single-ended
input, apply your calibration voltages between the channel 0 positive input and the ground
system you are using (refer to Chapter 2, Configuration and Installation, for instructions on
using single-ended input connections).

Bipolar Input Calibration Procedure

If your board is configured for bipolar input, which provides the ranges -5 to +5 V or

-10 to +10 V, then complete the following procedure in the order given. This procedure assumes
that ADC readings are in the range -2,048 to +2,047.

1. Adjust the Amplifier Input Offset

To adjust the amplifier input offset, follow these steps:
a. Connect both ACH0 (pin 3 on the I/O connector) and ACH8 (pin 4) to AISENSE (pin 19).
b. Take analog input readings from channel 0 at the following gains:

• Both 1 and 500 for the AT-MIO-16L

• Both 1 and 8 for the AT-MIO-16H

c. Adjust trimpot R2 until the readings match to within one count at both gain settings.

2. Adjust the ADC Input Offset

To adjust the ADC input offset, apply an input voltage across ACH0 and ACH8. This input

1

+

voltage is V

/2 LSB and depends on the input range you selected:

-fs

Input Range Calibration Voltage

-10 to +10 V -9.99756 V

-5 to +5 V -4.99878 V

AT-MIO-16 User Manual 4-4 © National Instruments Corporation

Chapter 4 Calibration Procedures

a. Connect the calibration voltage across ACH0 (pin 3 on the I/O connector) and ACH8 (pin 4).

Connect the ground point on the calibration voltage source to AISENSE (pin 19).

b. Take analog input readings from channel 0 at a gain of 1 and adjust trimpot R6 until the ADC

readings flicker evenly between -2,048 and -2,047.

3. Adjust the Analog Input Gain

To adjust the analog input gain, apply an input voltage across ACH0 and ACH8. This input
voltage is V

3

-

/2 LSB and depends on the input range you selected:

+fs

Input Range Calibration Voltage

-10 to +10 V -9.99268 V

-5 to +5 V -4.99634 V

a. Connect the calibration voltage across ACH0 (pin 3 on the I/O connector) and ACH8 (pin 4).

Connect the ground point on the calibration voltage source to AISENSE (pin 19).

b. Take analog input readings from channel 0 at a gain of 1 and adjust trimpot R1 until the ADC

readings flicker evenly between 2,046 and 2,047.

Unipolar Input Calibration Procedure

If your board is configured for unipolar input, which provides an input range of 0 to +10 V, then
complete the following procedure in the order given. This procedure assumes that ADC readings
are in the range 0 to +4,095.

1. Adjust the Amplifier Input Offset

To adjust the amplifier input offset, follow these steps:
a. Connect both ACH0 (pin 3 on the I/O connector) and ACH8 (pin 4) to AISENSE (pin 19).
b. Take analog input readings from channel 0 at a gain of 1 and adjust trimpot R8 until a

reading of roughly two counts is returned.

c. Take analog input readings from channel 0 at the following gains:

• Both 1 and 500 for the AT-MIO-16L

• Both 1 and 8 for the AT-MIO-16H

d. Adjust trimpot R2 until the readings at each gain setting match to within one count of each

other.

© National Instruments Corporation 4-5 AT-MIO-16 User Manual

Calibration Procedures Chapter 4

2. Adjust the ADC Input Offset

To adjust the ADC input offset, apply an input voltage across ACH0 and ACH8. This input
voltage is 1.22 mV, or 0 V + 1/2 LSB.

a. Connect the calibration voltage (1.22 mV) across ACH0 (pin 3 on the I/O connector) and

ACH8 (pin 4). Connect the ground point on the calibration voltage source to AISENSE
(pin 19).

b. Take analog input readings from channel 0 at a gain of 1 and adjust trimpot R8 until the ADC

readings flicker evenly between zero and one.

3. Adjust the Analog Input Gain

To adjust the analog input gain, apply an input voltage across ACH0 and ACH8. This input
voltage is +9.99634 V, or V

- 3/2 LSB.

+fs

a. Connect the calibration voltage (+9.99634 V) across ACH0 (pin 3 on the I/O connector) and

ACH8 (pin 4). Connect the ground point on the calibration voltage source to AISENSE
(pin 19).

b. Take analog input readings from channel 0 at a gain of 1 and adjust trimpot R1 until the ADC

readings flicker evenly between 4,094 and 4,095.

Analog Output Calibration

To null error sources that affect the accuracy of the output voltages generated, you must calibrate
the analog output circuitry by adjusting the following potential sources of error:

• Analog output offset error

• Analog output gain error
Offset error in the analog output circuitry is the total of the voltage offsets that each component

in the circuitry contributes. This error appears as a voltage difference between the desired
voltage and the actual output voltage generated and is independent of the DAC setting. To
correct this offset gain error, set the DAC to negative full scale and adjust a trimpot until the
output voltage is the negative full-scale value ±

Gain error in the analog output circuitry is the product of the gains that each component in the
circuitry contributes. This error appears as a voltage difference between the desired voltage and
the actual output voltage generated, which depends on the DAC setting. To correct this gain
error, set the DAC to positive full scale and adjust a trimpot until the output voltage corresponds
to the positive full-scale value ±

1

/2 LSB.

1

/2 LSB.

AT-MIO-16 User Manual 4-6 © National Instruments Corporation

Chapter 4 Calibration Procedures

Board Configuration

The calibration procedure differs depending on whether you select the bipolar or the unipolar
output configuration. A procedure for each configuration is described in the following sections.
These calibration procedures assume that you have selected the internal voltage reference
(+10 V) for the analog output channel to be calibrated.

To calibrate your board to an external reference input (DC only), you must recalculate the
desired output voltages to which you want the board to be calibrated.

• For bipolar output:
– 1 LSB = V

–V
–V

-fs

+fs

= -V

= V

extref

extref

/2,048 (therefore, 1/2 LSB = V

extref

- 1 LSB

extref

/4,096)

• For unipolar output:
– 1 LSB = V

–V
–V

= 0 V

-fs

= V

+fs

extref

/4,096 (therefore, 1/2 LSB = V

extref

- 1 LSB

extref

/8,192)

To calibrate to your own external reference, you should write your own procedures using the
following procedures as a guide. Substitute your calculated voltages for those given.

Bipolar Output Calibration Procedure

If your board is configured for bipolar output and two's complement mode, which provides an
output range of -10 to +10 V, complete the following procedure in the order given.

1. Adjust the Analog Output Offset

To adjust the analog output offset, measure the output voltage generated with the DAC set at
negative full scale (0). This output voltage should be V

= -10 V, and 1/2 LSB = 2.44 mV.

V

-fs

±1/2 LSB. For bipolar output,

-fs

• For analog output channel 0:
a. Connect the voltmeter between DAC0OUT (pin 20 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to -10 V by writing -2,048 to the DAC.
c. Adjust trimpot R7 until the output voltage read is -10 V ±2.44 mV, that is, between

-10.00244 V and -9.99756 V.

© National Instruments Corporation 4-7 AT-MIO-16 User Manual

Calibration Procedures Chapter 4

• For analog output channel 1:
a. Connect the voltmeter between DAC1OUT (pin 21 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to -10 V by writing -2,048 to the DAC.
c. Adjust trimpot R3 until the output voltage read is -10 V ± 2.44 mV, that is, between

-10.00244 V and -9.99756 V.

2. Adjust the Analog Output Gain

To adjust the analog output gain, measure the output voltage generated with the DAC set at
positive full scale (2,047). This output voltage should be V

= +9.99512 V, and 1/2 LSB = 2.44 mV.

V

+fs

±1/2 LSB. For bipolar output,

+fs

• For analog output channel 0:
a. Connect the voltmeter between DAC0OUT (pin 20 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to +9.99512 V by writing 2,047 to the DAC.
c. Adjust trimpot R5 until the output voltage read is +9.99512 V ±2.44 mV, that is, between

9.99268 V and 9.99756 V.

• For analog output channel 1:
a. Connect the voltmeter between DAC1OUT (pin 21 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to +9.99512 V by writing 2,047 to the DAC.
c. Adjust trimpot R4 until the output voltage read is +9.99512 V ±2.44 mV, that is, between

9.99756 V and 9.99268 V.

Unipolar Output Calibration Procedure

If your analog output channel is configured for unipolar output, which provides an output range
of 0 to +10 V, calibrate your board by performing the following procedure.

1. Adjust the Analog Output Offset

To adjust the analog output offset, measure the output voltage generated with the DAC set at
zero. This output voltage should be V

1

/2 LSB = 1.22 mV.

AT-MIO-16 User Manual 4-8 © National Instruments Corporation

±1/2 LSB. For unipolar output, V

-fs

= 0 V, and

-fs

Chapter 4 Calibration Procedures

• For analog output channel 0:
a. Connect the voltmeter between DAC0OUT (pin 20 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to 0 V by writing 0 to the DAC.
c. Adjust trimpot R7 until the output voltage read is 0 V ±1.22 mV.

• For analog output channel 1:
a. Connect the voltmeter between DAC1OUT (pin 21 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to 0 V by writing 0 to the DAC.
c. Adjust trimpot R3 until the output voltage read is 0 V ±1.22 mV.

2. Adjust the Analog Output Gain

To adjust the analog output gain, measure the output voltage generated with the DAC set at
positive full scale (4,095). This output voltage should be V

= +9.99756 V, and

V

+fs

1

/2 LSB = 1.22 mV.

±1/2 LSB. For unipolar output,

+fs

• For analog output channel 0:
a. Connect the voltmeter between DAC0OUT (pin 20 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to +9.99756 V by writing 4,095 to the DAC.
c. Adjust trimpot R5 until the output voltage read is +9.99756 V ±1.22 mV, that is, between

9.99634 V and 9.99878 V.

• For analog output channel 1:
a. Connect the voltmeter between DAC1OUT (pin 21 on the I/O connector) and AOGND

(pin 23).

b. Set the analog output channel to +9.99756 V by writing 4,095 to the DAC.
c. Adjust trimpot R4 until the output voltage read is +9.99756 V ±1.22 mV, that is, between

9.99634 V and 9.99878 V.

© National Instruments Corporation 4-9 AT-MIO-16 User Manual

Appendix A Specifications

This appendix lists the specifications for the AT-MIO-16. These specifications are typical at 25° C unless otherwise
noted.

Analog Input

Input Characteristics

Number of channels 16 single-ended or 8 differential,

jumper-selectable
Type of ADC Sampling, successive approximation
Resolution 12 bits, 1 in 4,096
Max sampling rate 100 kS/s
Input signal ranges

AT-MIO-16H and AT-MIO-16DH Board Gain

(Software

Selectable)

1 ±10 V ±5 0 to 10 V
2
4
8

±10 V

±5 V

±2.5 V

±1.25 V

Board Range

(Jumper Selectable)

±5 V

±2.5
±1.25 V
±0.63 V

0 to 10 V

0 to 5 V

0 to 2.5 V

0 to 1.25 V

AT-MIO-16L and AT-MIO-16DL Board Gain

(Software

Selectable)

±10 V ±5 V 0 to 10 V

1 ±10 V ±5 0 to 10 V

10
100
500

Input coupling DC
Max working voltage (signal + common
mode) Each input should remain within 12 V

of AIGND

Overvoltage protection ±35 V powered on, ±20 V powered off

Inputs protected ACH <0..15>
FIFO buffer size 16 samples
Data transfers DMA, interrupts, programmed I/O
DMA modes Demand

±1 V

±0.1 V

±0.02 V

Board Range

(Jumper Selectable)

±0.5
±0.05 V
±0.01 V

Transfer Characteristics

Relative accuracy ±0.9 LSB typical, ±1.5 LSB max
DNL ±0.50 LSB typical, ±0.95 LSB max

0 to 1 V

0 to 0.1 V

0 to 0.02 V

© National Instruments Corporation A-1 AT-MIO-16 User Manual

Specifications Appendix A

No missing codes 12 bits, guaranteed
Offset error

Pregain error after calibration ±2.44 µV (-L board)
Pregain error before calibration ±153 µV (-H board)
Postgain error after calibration ±1.22 mV max
Postgain error before calibration ±85 V max

Gain error (relative to calibration reference)

After calibration 0.0244% of reading (244 ppm) max
Before calibration 0.85% of reading (8,500 ppm) max
Gain ≠ 1 with gain error adjusted to 0

at gain = 1 0.02% of reading (200 ppm) max

Amplifier Characteristics

Input impedance 1 GΩ in parallel with 50 pF
Input bias current ±25 nA
Input offset current ±15 nA

CMRR

Gain CMRR

1

10

100

Dynamic Characteristics

Bandwidth

Small signal (-3 dB) 650 kHz @ gain = 1

Settling time to full-scale step

System noise (including quantization error)

Slew rate 5.0 V/µs

Gain Accuracy

±0.024%

(±1 LSB)

≤10
100
500

Gain 20 V Range 10 V Range

≤10
100
500

10 µs
14 µs
47 µs

0.10 LSBrms

0.15 LSBrms

0.30 LSBrms

DC to 100 Hz

75 dB
95 dB

105 dB

±0.012%

(±0.5 LSB)

10 µs
14 µs
50 µs

0.20 LSBrms

0.20 LSBrms

0.40 LSBrms

Stability

Recommended warm-up time 15 min
Offset temperature coefficient

Pregain 6 µV/°C
Postgain 160 µV/°C

Onboard calibration reference

Level 2.5 V ±10 mV
Temperature coefficient 10 ppm/°C max

Long-term stability 20 ppm 1,000 hr

AT-MIO-16 User Manual A-2 © National Instruments Corporation

Appendix A Specifications

Analog Output

Output Characteristics

Number of channels 2 voltage
Resolution 12 bits, 1 in 4,096
Max update rate 250 kS/s
Type of DAC Double-buffered, multiplying
Data transfers Interrupts, programmed I/O

Transfer Characteristics

Relative accuracy (INL)

Bipolar range ±0.25 LSB typical, ±0.5 LSB max
Unipolar range ±0.50 LSB typical, ±1.0 LSB max

DNL ±0.2 LSB typical, ±1 LSB max
Monotonicity 12 bits, guaranteed
Offset error

After calibration 488 µV max
Before calibration ±64 mV max

Gain error (relative to internal reference)

After calibration ±0.017% of reading (170 ppm) max
Before calibration ±0.77% of reading (7,700 ppm) max

Voltage Output

Ranges ±10 V, 0–10 V, jumper selectable
Output coupling DC
Output impedance ≤ 0.2 Ω
Current drive ±2 mA max
Protection Short-circuit protection
Power-on state Undetermined
External reference input

Range ±10 V
Overvoltage protection ±25 V powered on
Input impedance 11 kΩ

Dynamic Characteristics

Settling time to 0.024% FSR 4 µs for a 20 V step
Slew rate 30 V/µs

Noise 1 mVrms, DC to 1 MHz

© National Instruments Corporation A-3 AT-MIO-16 User Manual

Specifications Appendix A

Digital I/O

Number of channels 8 I/O
Compatibility TTL

Digital logic levels

Power on state Configured as input
Data transfers Programmed I/O

Level Min Max

Input low voltage
Input high voltage
Input low current
(V

= 0.4 V)

in

Input high current
(V

= 2.7 V)

in

Output low voltage
(I

= 24 A)

out

Output high voltage
(I

out

= -2.6 A)

2.4 V

0 V
2 V

0.8 V
6 V

-20 µA
20 µA

0.5 V

Timing I/O

Number of channels 3 counter/timers, 1 frequency scalers
Resolution

Counter/timers 16 bits
Frequency scalers 4 bits

Compatibility TTL, pulled high with 4.7 kΩ resistors
Base clocks available 1 MHz, 100 kHz, 10 kHz, 1 kHz, 100 Hz
Base clock accuracy ± 0.01 %
Max source frequency 6.897 MHz
Min source pulse duration 70 ns
Min gate pulse duration 145 s
Data transfers Programmed I/O

Triggers

Digital Trigger

Compatibility TTL
Response Falling edge
Pulse width 50 ns min

RTSI

Trigger lines 7

Bus Interface Slave

AT-MIO-16 User Manual A-4 © National Instruments Corporation

Appendix A Specifications

Power Requirement

+5 VDC (±5 %) 1.6 A

Physical

Dimensions 13.3 by 3.9 in. (33.782 by 9.906 cm)
I/O connector 50-pin male ribbon connector
Form factor AT

Environment

Operating temperature 0° to 70° C
Storage temperature -55° to 150° C
Relative humidity 5% to 90% noncondensing

© National Instruments Corporation A-5 AT-MIO-16 User Manual

Appendix B Revisions A through C Parts Locator Diagram

This appendix contains the parts locator diagram for revisions A through C of the AT-MIO-16
board.

© National Instruments Corporation B-1 AT-MIO-16 User Manual

Appendix C Customer Communication

For your convenience, this appendix contains forms to help you gather the information necessary
to help us solve technical problems you might have as well as a form you can use to comment on
the product documentation. Filling out a copy of the Technical Support Form before contacting
National Instruments helps us help you better and faster.

National Instruments provides comprehensive technical assistance around the world. In the U.S.
and Canada, applications engineers are available Monday through Friday from 8:00 a.m. to
6:00 p.m. (central time). In other countries, contact the nearest branch office. You may fax
questions to us at any time.

Corporate Headquarters

[phone]
Technical support fax: [phone]

[phone]

Branch Offices Phone Number Fax Number

Australia [phone] (03) 879 9179
Austria [phone] (0662) 437010-19
Belgium 02/757.00.20 02/757.03.11
Denmark 45 76 26 00 45 76 71 11
Finland (90) 527 2321 (90) 502 2930
France (1) 48 14 24 00 (1) 48 14 24 14
Germany 089/741 31 30 089/714 60 35
Italy 02/48301892 02/48301915
Japan [phone] (03) 3788-1923
Mexico 95 800 010 0793 95 800 010 0793
Netherlands 03480-33466 03480-30673
Norway 32-848400 32-848600
Singapore 2265886 2265887
Spain (91) 640 0085 (91) 640 0533
Sweden 08-730 49 70 08-730 43 70
Switzerland 056/20 51 51 056/20 51 55
Taiwan 02 377 1200 02 737 4644
U.K. 0635 523545 0635 523154

© National Instruments Corporation C-1 AT-MIO-16 User Manual

Technical Support Form

___________________________________________________

Photocopy this form and update it each time you make changes to your software or hardware, and use the completed
copy of this form as a reference for your current configuration. Completing this form accurately before contacting
National Instruments for technical support helps our applications engineers answer your questions more efficiently.

If you are using any National Instruments hardware or software products related to this problem, include the
configuration forms from their user manuals. Include additional pages if necessary.

Name
Company
Address

Fax ( ) Phone ( )
Computer brand Model Processor

Operating system
Speed MHz RAM MB Display adapter
Mouse yes no Other adapters installed
Hard disk capacity MB Brand
Instruments used

National Instruments hardware product model Revision

Configuration

National Instruments software product Version

Configuration

The problem is

List any error messages

The following steps will reproduce the problem

AT-MIO-16 Hardware and Software
Configuration Form

Record the settings and revisions of your hardware and software on the line to the right of each item. Complete a
new copy of this form each time you revise your software or hardware configuration, and use this form as a
reference for your current configuration. Completing this form accurately before contacting National Instruments
for technical support helps our applications engineers answer your questions more efficiently.

National Instruments Products

• AT-MIO-16 Model Number (For example,
AT-MIO-16L-9) _____________________________________________

• AT-MIO-16 Revision _____________________________________________

• Interrupt Level of AT-MIO-16
(Factory Setting: 10) _____________________________________________

• DMA Channels of AT-MIO-16
(Factory Setting: 6 and 7) _____________________________________________

• Base I/O Address of AT-MIO-16
(Factory Setting: hex 0220) _____________________________________________

• Programming Choice
(NI-DAQ, LabVIEW, LabWindows or other) _____________________________________________

• Software Version _____________________________________________

Other Products

• Computer Make and Model _____________________________________________

• Microprocessor _____________________________________________

• Clock Frequency _____________________________________________

• Type of Video Board Installed _____________________________________________

• Operating System (DOS or Windows) _____________________________________________

• Operating System Version _____________________________________________

• Programming Language _____________________________________________

• Programming Language Version _____________________________________________

• Other Boards in System _____________________________________________

• Base I/O Address of Other Boards _____________________________________________

• DMA Channels of Other Boards _____________________________________________

• Interrupt Level of Other Boards _____________________________________________

Documentation Comment Form

National Instruments encourages you to comment on the documentation supplied with our products. This
information helps us provide quality products to meet your needs.

Title: AT-MIO-16 User Manual
Edition Date: February 1995
Part Number: 320476-01
Please comment on the completeness, clarity, and organization of the manual.

If you find errors in the manual, please record the page numbers and describe the errors.

Thank you for your help.
Name

Title
Company
Address

Phone ( )

Mail to: Technical Publications Department Fax to: Technical Publications Department

National Instruments Corporation National Instruments Corporation
6504 Bridge Point Parkway, MS 53-02 MS 53-02
Austin, TX 78730-5039 [phone]

Register-Level Programmer Manual
Request Form

National Instruments offers a register-level programmer manual at no charge to customers who are not using
National Instruments software.

Title: AT-MIO-16 Register-Level Programmer Manual
Part Number: 340695-01
Please indicate your reasons for obtaining the register-level programmer manual. Check all that apply.

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.
Other. Please explain.

Thank you for your help.
Name

Title
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Address

Phone ( )
Mail to: Data Entry Department Fax to: Data Entry Department

National Instruments Corporation National Instruments Corporation
6504 Bridge Point Parkway [phone]
Austin, TX 78730-5039

Glossary

___________________________________________________

Prefix Meaning Value

p- pico­n- nano­µ- micro-

m- milli-

k- kilo- 10

M- mega- 10

G- giga- 10

% percent
± plus or minus
˚ degrees
/ per
+ positive of, or plus
– negative of, or minus

≠ not equal to
√ square root of

+5V +5 VDC source signal
A amperes
AC alternating current
ACH analog input channel signal
A/D analog-to-digital
ADC A/D converter
ADIO digital input/output port A signal
AIGND analog input ground signal
AISENSE analog input sense signal
ANSI American National Standards Institute
AOGND analog output ground signal
AWG American Wire Gauge
BDIO digital input/output port B signal
C Celsius
CMRR common-mode rejection ratio
CVI C Virtual Instrument
D/A digital-to-analog
DAC D/A converter
DAC0WR analog channel 0 output
DAC1WR analog channel 1 output
dB decibels
DC direct current
DIFF differential mode

10
10
10
10

12

-

9

-

6

-

3

-

3
6
9

© National Instruments Corporation Glossary-1 AT-MIO-16 User Manual

Glossary

DIGGND digital ground signal
DIP dual inline package
DMA direct memory access
EISA Extended Industry Standard Architecture
EXTCONV external Convert Signal
EXTREF external reference signal
EXTSTROBE external strobe signal
FIFO first-in-first-out
FSR full-scale ratio
ft feet
hex hexadecimal
Hz hertz
in. inches
INL integral nonlinearity
I/O input/output
IRQ interrupt lines
I
I
I
I

IH
IL
OH
OL

current, input high
current, input low
current, output high

current, output low
LED light-emitting diode
LS low-power Schottky
LSB least significant bit
max maximum
min minimum
MSB most significant bit
mux multiplexer
NRSE nonreferenced single-ended mode
Ω ohms
OUT output
PC personal computer
ppm parts per million
rms root mean square
RSE referenced single-ended mode
RTSI Real-Time System Integration
RTSICLK Real-Time System Integration clock
s seconds
S samples
SCANCLK scan clock signal
SCXI Signal Conditioning eXtensions for Instrumentation
SDK Software Developer’s Toolkit
SE single-ended inputs
S/H sample and hold
STARTTRIG external trigger signal
STOPTRIG stop trigger signal
TC terminal count
THD total harmonic distortion
TTL transistor-transistor logic
V volts

LabWindows User Manual Glossary-2 © National Instruments Corporation

VDC volts direct current
V
V
V
V
V
V
V

fs
IH
IL
in
OH
OL
ref

output offset voltage

volts, input high

volts, input low

volts in

volts, output high

volts, output low

reference voltage
Vrms volts, root mean square

Glossary

© National Instruments Corporation Glossary-3 LabWindows User Manual

Index

Numbers/Symbols

+5 V pin

definition, 3-3
warning against connecting to

ground, 3-16

A

ACH<O..15> signal

description, 3-2

input ranges and maximum ratings, 3-5
ADIO<0..3> signal, 3-3, 3-13
AIGND signal, 3-2, 3-4
AISENSE signal, 3-3
analog input calibration, 4-3 to 4-6

bipolar input calibration procedure, 4-4

to 4-5
board configuration, 4-4
unipolar input calibration procedure, 4-5

to 4-6

analog input configuration, 2-8 to 2-12

DIFF (differential) input, 2-9
factory settings, 2-6 to 2-7
input mode, 2-9
input polarity and range, 2-10 to 2-11
jumper settings quick reference (table),

2-6 to 2-7
NRSE input (16 channels), 2-10
RSE input (16 channels), 2-9 to 2-10
selecting input ranges, 2-11 to 2-12

actual range and precision vs. range

selection and gain (table), 2-12

analog input signal connections

instrumentation amplifier, 3-5 to 3-6
pin descriptions, 3-3 to 3-4
warning against exceeding input

ranges, 3-5

analog input specifications, A-1 to A-2

amplifier characteristics, A-2
dynamic characteristics, A-2
input characteristics, A-1
stability, A-2
transfer characteristics, A-1

analog output calibration, 4-6 to 4-9

bipolar output calibration procedure, 4-7

to 4-8
board configuration, 4-7
unipolar output calibration procedure,

4-8 to 4-9

analog output configuration, 2-12 to 2-15

circuitry block diagram, 2-13
data coding, 2-14

data mode (table), 2-15
output range selection and precision

(table), 2-15

jumper settings quick reference (table),

2-6 to 2-7
output reference, 2-13 to 2-14

internal and external reference

selection (table), 2-14

polarity selection, 2-14

bipolar and unipolar (table), 2-15
output range selection and precision

(table), 2-15

RTSI bus clock selection, 2-17

analog output signal connections, 3-12

to 3-13

analog output specifications, A-3

dynamic characteristics, A-3
output characteristics, A-3
transfer characteristics, A-3
voltage output, A-3

AOGND signal, 3-3, 3-13
AT bus interface configuration, 2-1 to 2-5

base I/O address selection, 2-3 to 2-4
DMA channel selection, 2-4 to 2-5
factory default settings (table), 2-1
interrupt selection, 2-5
parts locator diagram

revision D and later, 2-2
revisions A through C, B-2

AT-MIO-16. See also specifications.

definition of, ix
description of, 1-1
interface with SCXI systems, 1-1
parts locator diagram

revision D and later, 2-2
revisions A through C, B-2

© National Instruments Corporation Index-1 AT-MIO-16 User Manual

Index

software programming choices, 1-2

to 1-5

LabVIEW and LabWindows

software, 1-2 to 1-3
NI-DAQ driver software, 1-3 to 1-4
register-level programming, 1-5

unpacking, 1-5
what you need to get started, 1-1

AT-MIO-16 instrumentation amplifier, 3-5

to 3-6

B

base I/O address configuration, 2-3 to 2-4

example switch settings

(illustration), 2-3
factory default settings (table), 2-1
switch settings with corresponding base

I/O address and base I/O address

space (table), 2-4
verifying the address space, 2-3

BDIO<0..3> signal, 3-3, 3-13
bipolar input

calibration procedure, 4-4 to 4-5
configuration, 2-10 to 2-11

bipolar output

calibration procedure, 4-7 to 4-8
configuration, 2-14 to 2-15

board configuration. See calibration

procedures; configuration.

bus interface specifications, A-4

C

cabling considerations, 3-26 to 3-27
calibration procedures

analog input calibration, 4-3 to 4-6

bipolar input calibration procedure,

4-4 to 4-5
board configuration, 4-4
unipolar input calibration procedure,

4-5 to 4-6

analog output calibration, 4-6 to 4-9

bipolar output calibration procedure,

4-7 to 4-8
board configuration, 4-7

unipolar output calibration

procedure, 4-8 to 4-9
equipment requirements, 4-1
trimpots, 4-2

common mode signal rejection
considerations, 3-11 to 3-12
configuration. See also installation; jumper

settings; signal connections.

analog input configuration, 2-8 to 2-12

data acquisition circuitry block

diagram, 2-8

DIFF (differential) input, 2-9
input mode, 2-9
input polarity and range, 2-10 to 2-11
NRSE input (16 channels), 2-10
RSE input (16 channels), 2-9 to 2-10
selecting input ranges, 2-11 to 2-12

actual range and precision vs.

range selection and gain
(table), 2-12

analog I/O jumper settings quick

reference (table), 2-6 to 2-7

analog output configuration, 2-12

to 2-15
block diagram, 2-13
data coding, 2-14

data mode (table), 2-15
output range selection and

precision (table), 2-15

output reference, 2-13 to 2-14

external reference selection

(table), 2-14

internal reference selection

(table), 2-14

polarity selection, 2-14

bipolar and unipolar (table), 2-15
output range selection and

precision (table), 2-15

AT bus interface, 2-1 to 2-5

base I/O address selection, 2-3 to 2-4
DMA channel selection, 2-4 to 2-5
factory default settings (table), 2-1
interrupt selection, 2-5

base I/O address selection, 2-3 to 2-4

AT bus factory default settings

(table), 2-1

example switch settings

(illustration), 2-3

AT-MIO-16 User Manual Index-2 © National Instruments Corporation

Index

switch settings with corresponding

base I/O address and base I/O
address space (table), 2-4

verifying the address space, 2-3
cabling considerations, 3-26 to 3-27
digital I/O configuration, 2-15 to 2-16
DMA channel selection, 2-4 to 2-5

AT bus factory default settings

(table), 2-1

jumper settings (table), 2-5
field wiring considerations, 3-25 to 3-26
interrupt selection, 2-5

AT bus factory default settings

(table), 2-1

jumper settings (table), 2-5
overview, 2-1
parts locator diagram, B-2

revision D and later, 2-2

revisions A through C, B-2
RTSI bus clock selection, 2-17

customer communication, x, C-1

D

DAC0OUT signal, 3-3, 3-12
DAC1OUT signal, 3-3, 3-12
data acquisition timing connections, 3-16

to 3-25
EXTCONV* signal, 3-17
EXTSTROBE* signal, 3-16 to 3-17
SCANCLK signal, 3-16
STARTTRIG* signal, 3-18
STOPTRIG signal, 3-18

data mode configuration

analog output data coding, 2-14
straight binary (table), 2-15
two's complement (table), 2-15

differential connections

floating signal sources, 3-8 to 3-9
general considerations, 3-7
ground-referenced signal sources, 3-8

differential input

configuration, 2-9
definition, 2-9

DIGGND signal, 3-3, 3-13
digital I/O

configuration, 2-15 to 2-16
signal connections, 3-13 to 3-15

specifications, A-4

DMA channel

configuration, 2-4 to 2-5
factory default settings (table), 2-1
jumper settings (table), 2-5

documentation

conventions used in the manual, x
organization, ix
related documentation, x

E

environment noise, minimizing, 3-25 to 3-26
environment specifications, A-5
event counting, 3-21

event-counting application with external

switch gating (illustration), 3-22

EXTCONV* signal

description, 3-4
RTSI switch connections, 3-16

timing connections, 3-17
external reference selection (table), 2-14
EXTREF signal, 3-3, 3-12
EXTSTROBE* signal, 3-3, 3-17

F

fax technical support, C-1
field wiring considerations, 3-25 to 3-26
floating signal sources

description, 3-6

differential connections, 3-8 to 3-9

recommended configurations (table), 3-7

single-ended connections, 3-10
FOUT signal, 3-4, 3-16, 3-25
frequency measurement, 3-22 to 3-23
fuse, 3-3

G

GATE, OUT, and SOURCE timing signals,

3-19 to 3-25
GATE1 signal, 3-4, 3-16
GATE2 signal, 3-4
GATE3 signal, 3-21
GATE5 signal, 3-4

© National Instruments Corporation Index-3 AT-MIO-16 User Manual

Index

general-purpose connections, 3-19 to 3-25

counter block diagram, 3-20
event-counting application with external

switch gating (illustration), 3-22
frequency measurement, 3-22 to 3-23
frequency measurement application

(illustration), 3-23
GATE, SOURCE, and OUT signals,

3-19 to 3-25
input and output ratings, 3-23 to 3-24
time-lapse measurement, 3-22
timing I/O circuitry block diagram, 3-19
timing requirements (illustration), 3-24
timing signals, 3-19 to 3-25

ground-referenced signal sources

definition and requirements, 3-6
differential connections, 3-8
recommended configurations (table), 3-7
single-ended connections, 3-11

H

hardware installation, 2-17 to 2-18

I

input configurations

common mode signal rejection, 3-11

to 3-12
differential input

floating signal sources, 3-8 to 3-9
general considerations, 3-7
ground-referenced signal

sources, 3-8

recommended configurations for ground-

referenced and floating signal

sources (table), 3-7
single-ended connections

floating signal (RSE) sources, 3-10
general considerations, 3-10
grounded signal (NRSE)

sources, 3-11

input polarity, configuring. See polarity

configuration.

installation. See also configuration.

hardware installation, 2-17 to 2-18
unpacking the AT-MIO-16, 1-5

instrumentation amplifier, 3-5 to 3-6
internal reference selection (table), 2-14
interrupts

configuration, 2-5
factory default settings (table), 2-1
jumper settings (table), 2-5

I/O connector pin assignments, 3-1 to 3-2

signal description, 3-3 to 3-4

J

jumper settings

analog input

DIFF (differential) input

configuration, 2-9
input polarity and range (table), 2-11
NRSE input (16 channels), 2-10
RSE input (16 channels), 2-9 to 2-10

analog I/O jumper settings quick

reference (table), 2-6 to 2-7

analog output

data mode settings (table), 2-15
polarity settings (table), 2-15

AT bus interface settings, 2-1

factory default settings (table), 2-1

base I/O address, 2-3

example settings (illustration), 2-3
switch settings with base I/O address

and address space (table), 2-4

bipolar output selection (table), 2-15
DMA selection, 2-4 to 2-5
external reference selection (table), 2-14
input polarity and input range

(table), 2-11

internal reference factory setting

(table), 2-14
interrupt selection, 2-5
overview, 2-1
RTSI bus clock selection, 2-17
straight binary mode (table), 2-15
two's complement mode (table), 2-15
unipolar output selection (table), 2-15

L

LabVIEW software, 1-2 to 1-3
LabWindows software, 1-2 to 1-3

AT-MIO-16 User Manual Index-4 © National Instruments Corporation

Index

N

NI-DAQ driver software, 1-3 to 1-4

interface with programming

languages, 1-4

relationship between programming

environment, NI-DAQ, and

hardware (illustration), 1-4
noise, minimizing, 3-25 to 3-26
nonreferenced single-ended (NRSE) input

configuration, 2-10
definition, 2-10
single-ended connections for grounded

signal sources, 3-11
NRSE input. See nonreferenced single-

ended (NRSE) input.

O

OUT, GATE, and SOURCE timing signals,

3-19 to 3-25
OUT1 signal, 3-4, 3-16
OUT2 signal, 3-4, 3-16, 3-21
OUT3 signal, 3-21
OUT4 signal, 3-21
OUT5 signal, 3-4, 3-16
output polarity, configuring. See polarity

configuration.

jumper settings (table), 2-15

output range and precision

(table), 2-15
power connections, 3-16
power requirement specifications, A-5
programming, register-level, 1-5. See also

software for AT-MIO-16 board.
pulse-width measurement, 3-22
pulses, producing, 3-21

R

referenced single-ended (RSE) input

configuration, 2-9 to 2-10
definition, 2-9
single-ended connections for floating

signal sources, 3-10
register-level programming, 1-5
RSE input. See referenced single-ended

(RSE) input.

RTSI bus

clock selection, 2-17
definition, 1-1
signal connections, 3-15 to 3-16

block diagram, 3-15

RTSI switch, 3-16

S

P

physical specifications, A-5
pin assignments for I/O connector, 3-2
polarity calibration procedure
bipolar input, 4-4 to 4-5

bipolar output, 4-7 to 4-8
unipolar input, 4-5 to 4-6
unipolar output, 4-8 to 4-9

polarity configuration

input polarity and input range, 2-10

to 2-11

actual range and precision vs. range

selection and gain (table), 2-12

considerations for selecting, 2-11

to 2-12

jumper settings (table), 2-11

output polarity, 2-14

© National Instruments Corporation Index-5 AT-MIO-16 User Manual

SCANCLK signal

data acquisition timing connections, 3-16
description, 3-3

general-purpose timing, 3-21
SCXI systems, 1-1
signal connections

analog input signal connections, 3-4

to 3-6
instrumentation amplifier, 3-5 to 3-6
warning against exceeding input

ranges, 3-5

analog output signal connections, 3-12

to 3-13

cabling considerations, 3-26 to 3-27
digital I/O signal connections, 3-13

to 3-15

field wiring considerations, 3-25 to 3-26
floating signal sources, 3-6

Index

ground-referenced signal sources, 3-6
input configurations

common mode signal rejection, 3-11

to 3-12

differential connections

floating signal sources, 3-8 to 3-9
general considerations, 3-6
grounded signal sources, 3-8

recommended configurations for

ground-referenced and floating

signal sources (table), 3-7
single-ended connections
floating signal (RSE) sources, 3-10

general considerations, 3-10
grounded signal (NRSE)

sources, 3-11

pin assignments for I/O connector, 3-2

pin descriptions, 3-3 to 3-4

power connections, 3-16
RTSI bus signal connections, 3-15

to 3-16

timing connections, 3-16 to 3-18

data acquisition timing connections,

3-16 to 3-18
general-purpose connections, 3-19

to 3-25
pins for, 3-16

timing I/O signals, 3-15
types of signal sources, 3-5
warning against exceeding ratings, 3-1

single-ended connections

floating signal (RSE) sources, 3-10
general considerations, 3-10
grounded signal (NRSE) sources, 3-11

single-ended input configuration

NRSE input (16 channels), 2-10
RSE input (16 channels), 2-9 to 2-10

software for AT-MIO-16 board

LabVIEW and LabWindows, 1-2 to 1-3
NI-DAQ driver software, 1-3 to 1-4
register-level programming, 1-5

SOURCE, OUT, and GATE timing signals,

3-19 to 3-25
SOURCE1 signal, 3-4
SOURCE2 signal, 3-4
SOURCE3 signal, 3-21
SOURCE5 signal, 3-4, 3-16, 3-21
specifications

analog input, A-1 to A-2

analog output, A-3
bus interface, A-4
digital I/O, A-4
environment, A-5
physical, A-5
power requirement, A-5
RTSI trigger lines, A-4
timing I/O, A-4

triggers, A-4
square waves, producing, 3-21
STARTTRIG* signal

description, 3-3

RTSI switch connections, 3-16

timing connections, 3-18
STOPTRIG* signal

data acquisition timing connections, 3-18

description, 3-3

RTSI switch connections, 3-16
straight binary mode output selection

(table), 2-15

switch settings. See jumper settings.

T

technical support, C-1
time-lapse measurements, 3-22
timing connections, 3-16 to 3-18

data acquisition timing connections, 3-16

to 3-18
EXTCONV signal, 3-17
EXTSTROBE signal, 3-17
SCANCLK signal, 3-16
STARTTRIG* signal, 3-18
STOPTRIG* signal, 3-18

general-purpose connections, 3-19

to 3-25
counter block diagram, 3-20
event-counting application with
external switch gating

(illustration), 3-22
frequency measurement, 3-22
frequency measurement application

(table), 3-23
GATE, SOURCE, and OUT signals,

3-19 to 3-25
input and output ratings, 3-23 to 3-24
time-lapse measurement, 3-22

AT-MIO-16 User Manual Index-6 © National Instruments Corporation

timing I/O circuitry block

diagram, 3-19

timing requirements

(illustration), 3-24

timing signals, 3-19 to 3-25

pins for, 3-16
timing I/O signals, 3-15
timing I/O specifications, A-4
trigger specifications, A-4
two's complement mode (table), 2-15

U

unipolar input

calibration procedure, 4-5 to 4-6

configuration, 2-10 to 2-11
unipolar output

calibration procedure, 4-8 to 4-9

configuration, 2-14 to 2-15
unpacking the AT-MIO-16, 1-5

Index

© National Instruments Corporation Index-7 AT-MIO-16 User Manual