National Instruments PC-LPM-16-PnP User Manual

PC-LPM-16/PnP

User Manual

Multifunction I/O Board for the PC

November 1996 Edition

Part Number 320287C-01



Copyright 1990, 1996 National Instruments Corporation. All Rights Reserved.

Internet Support

[e-mail]

E-mail:
FTP Site:
Web Address:

[e-mail]

ftp.natinst.com

http://www.natinst.com

Bulletin Board Support

BBS United States: [phone]
BBS United Kingdom: 01635 551422
BBS France: 01 48 65 15 59

Fax-on-Demand Support

[phone]

Telephone Support (U.S.)

Tel: [phone]
Fax: [phone]

International Offices

Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20,
Canada (Ontario) 905 785 0085, Canada (Québec) 514 694 8521, Denmark 45 76 26 00,
Finland 09 527 2321, France 01 48 14 24 24, Germany 089 741 31 30, Hong Kong 2645 3186,
Israel 03 5734815, Italy 02 413091, Japan 03 5472 2970, Korea 02 596 7456,
Mexico 5 520 2635, Netherlands 0348 433466, Norway 32 84 84 00, Singapore 2265886,
Spain 91 640 0085, Sweden 08 730 49 70, Switzerland 056 200 51 51, Taiwan 02 377 1200,
U.K. 01635 523545

National Instruments Corporate Headquarters

6504 Bridge Point Parkway Austin, TX 78730-5039 Tel: [phone]

Important Information

Warranty

Copyright

Trademarks

The PC-LPM-16 and PC-LPM-16PnP are 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.

XCEPT AS SPECIFIED HEREIN

E

SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE

C

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL

I

NSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER
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

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

Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or
mechanical, including photocopying, recording, storing in an information retrieval system, or translating, in whole or
in part, without the prior written consent of National Instruments Corporation.

LabVIEW, NI-DAQ, DAQ-STC, and SCXI are trademarks of National Instruments Corporation.
Product and company names listed are trademarks or trade names of their respective companies.

, N

ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND

. N

ATIONAL INSTRUMENTS

. This limitation of the liability of National

.

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.

Table

of

Contents

About This Manual

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

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

National Instruments Documentation............................................................................xi

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

Customer Communication.............................................................................................xii

Chapter 1
Introduction

About the PC-LPM-16/PnP............................................................................................1-1

What You Need to Get Started.......................................................................................1-2

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

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

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

Register-Level Programming...........................................................................1-4

Optional Equipment.......................................................................................................1-5

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

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

Chapter 2
Installation and Configuration

Hardware Installation.....................................................................................................2-1

Software Installation......................................................................................................2-2

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

Plug and Play...................................................................................................2-2

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

Non-Plug and Play...........................................................................................2-3

Chapter 3
Theory of Operation

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

PC I/O Channel Interface Circuitry................................................................................3-3

Analog Input and Data Acquisition Circuitry................................................................3-4

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National Instruments Corporation v PC-LPM-16/PnP User Manual

Table of Contents

Analog Input Circuitry.................................................................................... 3-5

Data Acquisition Timing Circuitry ................................................................. 3-6

Digital I/O Circuitry ..................................................................................................... 3-8

Timing I/O Circuitry...................................................................................................... 3-9

Chapter 4
Signal Connections

I/O Connector................................................................................................................ 4-1

Signal Connection Descriptions .................................................................................... 4-3

Analog Input Signal Connections ................................................................... 4-5

Digital I/O Signal Connections....................................................................... 4-6

Power Connections.......................................................................................... 4-7

Power Rating................................................................................................... 4-8

Timing Connections........................................................................................ 4-8

Single-Channel Data Acquisition ..................................................... 3-7

Multichannel Scanning Data Acquisition.........................................3-7

Data Acquisition Rates ..................................................................... 3-7

Connections for Signal Sources........................................................ 4-5

Data Acquisition Timing Connections .............................................4-8

General-Purpose Timing Signal Connections and General-Purpose

Counter Timing Signals.................................................................. 4-9

Appendix A
Specifications

Appendix B
MSM82C53 Data Sheet

Appendix C
Using Your PC-LPM-16 (Non-PnP) Board

Appendix D
Register-Level Programming

Appendix E
Customer Communication

PC-LPM-16/PnP User Manual vi

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National Instruments Corporation

Glossary

Index

Figures

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

Figure 3-1. PC-LPM-16PnP Block Diagram ...........................................................3-2

Figure 3-2. PC I/O Interface Circuitry Block Diagram ............................................3-3

Figure 3-3. Analog Input and Data Acquisition Circuitry Block Diagram ..............3-4

Figure 3-4. Digital I/O Circuitry Block Diagram .....................................................3-8

Figure 3-5. Timing I/O Circuitry Block Diagram ....................................................3-9

Figure 3-6. Counter Block Diagram .........................................................................3-10

Figure 4-1. PC-LPM-16PnP I/O Connector Pin Assignments .................................4-2

Figure 4-2. Analog Input Signal Connections ..........................................................4-6

Figure 4-3. Analog Input Signal Connections ..........................................................4-7

Figure 4-4. EXTCONV* Signal Timing ..................................................................4-9

Figure 4-5. Event-Counting Application with External Switch Gating ...................4-10

Figure 4-6. Frequency Measurement Application ....................................................4-11

Figure 4-7. General-Purpose Timing Signals ...........................................................4-12

Table of Contents

NI-DAQ, and Your Hardware ...............................................................1-4

Figure A-1. ADC Errors ............................................................................................A-6

Figure C-1. PC-LPM-16 Parts Locator Diagram ......................................................C-5

Figure C-2. Example Base I/O Address Switch Settings ..........................................C-7

Figure C-3. Interrupt Jumper Setting IRQ5 (Factory Setting) ..................................C-10

Figure C-4. Interrupt Jumper Setting for Disabling Interrupts .................................C-10

Figure C-5. Bipolar Input (±5 V) Jumper Configuration (Factory Setting) .............C-11

Figure C-6. Bipolar Input (±2.5 V) Jumper Configuration .......................................C-11

Figure C-7. Unipolar Input (0 to 10 V) Jumper Configuration .................................C-11

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National Instruments Corporation vii PC-LPM-16/PnP User Manual

Table of Contents

Tables

Table 4-1. Signal Connection Descriptions ............................................................ 4-3

Table C-1. Comparison of Characteristics .............................................................. C-1

Table C-2. PC Bus Interface Factory Settings ........................................................ C-7

Table C-3. Switch Settings with Corresponding Base I/O Address and

Table D-1. PC-LPM-16/PnP Register Map ............................................................ D-1

Table D-2. Unipolar Input Mode A/D Conversion Values ..................................... D-29

Table D-3. Bipolar Input Mode A/D Conversion Values ....................................... D-30

Base I/O Address Space ........................................................................ C-9

PC-LPM-16/PnP User Manual viii

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National Instruments Corporation

About

This

Manual

This manual describes the mechanical and electrical aspects of the
PC-LPM-16PnP and contains information concerning its installation,
operation, and programming. The PC-LPM-16PnP is a low-cost, low­power analog input, digital, and timing I/O board for the IBM PC/XT,
PC AT, Personal System/2 Models 25 and 30, and laptop compatible
computers.

This manual also applies to the PC-LPM-16, a non-Plug and Play board.
The boards are identical in functionality, programming, and
performance, except for the differences listed in Appendix C,

Your PC-LPM-16 (Non-PnP) Board

.

Using

Organization of This Manual

The

PC-LPM-16/PnP User Manual

• Chapter 1,
you need to get started, software programming choices, and
optional equipment, and explains how to unpack the
PC-LPM-16/PnP.

• Chapter 2
installation and configuration of the PC-LPM-16PnP.

• Chapter 3
PC-LPM-16PnP board and explains the operation of each
functional unit making up the board. This chapter also explains the
basic operation of the PC-LPM-16PnP circuitry.

• Chapter 4
output signal connections to your PC-LPM-16PnP board via the
I/O connector.

• Appendix A
PC-LPM-16PnP.

• Appendix B
sheet for the MSM82C53 CMOS programmable interval timer
(OKI Semiconductor).

Introduction

, Installation and Configuration

, Theory of Operation

, Signal Connections

, Specifications

, MSM82C53 Data Sheet

is organized as follows:

, describes the PC-LPM-16/PnP, lists what

, describes the

, includes an overview of the

, describes how to make input and

, lists the specifications of the

, contains a manufacturer data



National Instruments Corporation ix PC-LPM-16/PnP User Manual

About This Manual

• Appendix C
the differences between the PC-LPM-16PnP and the PC-LPM-16
non-PnP boards, the PC-LPM-16 board configuration, and
installing the PC-LPM-16 into your computer.

• Appendix D,
information related to register-level programming the
PC-LPM-16/PnP.

• Appendix E
use to request help from National Instruments or to comment on
our products.

• The

• The

Glossary

used in this manual, including abbreviations, acronyms, metric
prefixes, mnemonics, and symbols.

Index

number where the topic can be found.

, Using Your PC-LPM-16 (Non-PnP) Board

Register-Level Programming

, Customer Communication

contains an alphabetical list and description of terms

lists topics covered in this manual, including the page

Conventions Used in This Manual

The following conventions are used in this manual:

< > Angle brackets containing numbers separated by an ellipsis represent a

range, signal, or port (for example, ACH<0..7> stands for ACH0
through ACH7).

bold

bold italic

italic

monospace

NI-DAQ NI-DAQ refers to the NI-DAQ software for PC compatibles, unless

Bold text denotes menus, menu items, or dialog box buttons or options,

and error messages.

Bold italic text denotes a note, caution, or warning.
Italic text denotes emphasis, a cross reference, or an introduction to a

key concept.

Text in this font denotes text or characters that are to be literally input
from the keyboard, sections of code, programming examples, and
syntax examples. This font is also used for the proper names of disk
drives, paths, directories, programs, subprograms, subroutines, device
names, functions, operations, variables, filenames, and extensions, and
for statements and comments taken from program code.

otherwise noted.

, describes

, describes in detail

, contains forms you can

PC-LPM-16/PnP User Manual x

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National Instruments Corporation

About This Manual

Non-PnP Non-PnP (non-Plug and Play) means that the board requires you to

manually configure the product’s base address and interrupt level with
switches and jumpers. You must perform this configuration before
installing the board into your computer.

PC PC refers to the IBM PC/XT, PC AT, Personal System/2 Models 25

and 30, and laptop compatible computers.

PC-LPM-16/PnP PC-LPM-16/PnP refers to both the Plug and Play and the non-Plug and

Play versions of the board.
PC-LPM-16PnP PC-LPM-16PnP refers to the Plug and Play version of the board.
PC-LPM-16 PC-LPM-16 refers to the non-Plug and Play version of the board.
PnP PnP (Plug and Play) means that the board is fully compatible with the

industry-standard Plug and Play ISA Specification. All bus-related

configuration is performed through software, freeing you from

manually configuring jumpers or switches to set the product’s base

address and interrupt level. Plug and Play systems automatically

arbitrate and assign system resources to a PnP product.

Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and

terms are listed in the

Glossary

.

National Instruments Documentation

The

PC-LPM-16/PnP User Manual

set for your DAQ or SCXI system. You could have any of several types

of manuals depending on the hardware and software in your system.

Use the manuals you have as follows:

•

Getting Started with SCXI

manual you should read. It gives an overview of the SCXI system
and contains the most commonly needed information for the
modules, chassis, and software.

• Your SCXI hardware user manuals—If you are using SCXI, read
these manuals next for detailed information about signal
connections and module configuration. They also explain in
greater detail how the module works and contain application hints.

• Your DAQ hardware documentation—This documentation has
detailed information about the DAQ hardware that plugs into or is
connected to your computer. Use this documentation for hardware



National Instruments Corporation xi PC-LPM-16/PnP User Manual

is one piece of the documentation

—If you are using SCXI, this is the first

About This Manual

installation and configuration instructions, specification
information about your DAQ hardware, and application hints.

• Software documentation—Examples of software documentation
you may have are the LabVIEW, LabWindows/CVI
documentation sets, and the NI-DAQ documentation. After you set
up your hardware system, use either the application software
(LabVIEW or LabWindows/CVI) or the NI-DAQ documentation to
help you write your application. If you have a large, complicated
system, it is worthwhile to look through the software
documentation before you configure your hardware.

• Accessory installation guides or manuals—If you are using
accessory products, read the terminal block and cable assembly
installation guides. They explain how to physically connect the
relevant pieces of the system. Consult these guides when you are
making your connections.

•

SCXI Chassis User Manual

manual for maintenance information on the chassis and for
installation instructions.

Related Documentation

—If you are using SCXI, read this

The following document contains information that you may find helpful

as you read this manual:

• Your computer user or technical reference manual

Customer Communication

National Instruments wants to receive your comments on our products
and manuals. We are interested in the applications you develop with our
products, and we want to help if you have problems with them. To make
it easy for you to contact us, this manual contains comment and
configuration forms for you to complete. These forms are in
Appendix E,

PC-LPM-16/PnP User Manual xii

Customer Communication

, at the end of this manual.



National Instruments Corporation

Chapter

Introduction

This chapter describes the PC-LPM-16/PnP, lists what you need to get
started, software programming choices, and optional equipment, and
explains how to unpack the PC-LPM-16/PnP.

About the PC-LPM-16/PnP

The PC-LPM-16/PnP is a low-cost, low-power analog input, digital,
and timing I/O board for the PC. The board contains a 12-bit,
successive-approximation, self-calibrating ADC with 16 analog inputs,
8 lines of TTL-compatible digital input, and 8 lines of digital output.
The PC-LPM-16/PnP also contains two 16-bit counter/timer channels
for timing I/O.

The low cost of a PC-LPM-16/PnP-based system makes it ideal for
laboratory work in industrial and academic environments. The board’s
low power consumption and small size make the PC-LPM-16/PnP
especially suitable for laptop computers. The multichannel analog input
is useful in signal analysis and data logging. The 12-bit ADC is useful
in high-resolution applications such as chromatography, temperature
measurement, and DC voltage measurement. You can use the 16 TTL­compatible digital I/O lines for switching external devices such as
transistors and solid-state relays, for reading the status of external
digital logic, and for generating interrupts. You can use the
counter/timers to synchronize events, generate pulses, and measure
frequency and time. The PC-LPM-16/PnP, used in conjunction with
your computer, is a versatile, cost-effective platform for laboratory test,
measurement, and control.

1



National Instruments Corporation 1-1 PC-LPM-16/PnP User Manual

Chapter 1 Introduction

What You Need to Get Started

To set up and use your PC-LPM-16/PnP board, you will need the

following:

❏

PC-LPM-16/PnP board

❏

PC-LPM-16/PnP User Manual

❏

One of the following software packages and documentation:

NI-DAQ for PC Compatibles
LabVIEW for Windows
LabWindows/CVI for Windows

❏

Your computer

Software Programming Choices

There are several options to choose from when programming your
National Instruments DAQ and SCXI hardware. You can use
LabVIEW, LabWindows/CVI, NI-DAQ, or register-level
programming.

LabVIEW and LabWindows/CVI Application Software

LabVIEW and LabWindows/CVI are innovative program development
software packages for data acquisition and control applications.
LabVIEW uses graphical programming, whereas LabWindows/CVI
enhances traditional programming languages. Both packages include
extensive libraries for data acquisition, instrument control, data
analysis, and graphical data presentation.

LabVIEW features interactive graphics, a state-of-the-art user
interface, and a powerful graphical programming language. The
LabVIEW Data Acquisition VI Library, a series of VIs for using
LabVIEW with National Instruments DAQ hardware, is included with
LabVIEW. The LabVIEW Data Acquisition VI Library is functionally
equivalent to the NI-DAQ software.

LabWindows/CVI features interactive graphics, a state-of-the-art user
interface, and uses the ANSI standard C programming language. The
LabWindows/CVI Data Acquisition Library, a series of functions for
using LabWindows/CVI with National Instruments DAQ hardware, is

PC-LPM-16/PnP User Manual 1-2

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National Instruments Corporation

included with the NI-DAQ software kit. The LabWindows/CVI Data
Acquisition Library is functionally equivalent to the NI-DAQ software.

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

NI-DAQ Driver Software

The NI-DAQ driver software is included at no charge with all National
Instruments DAQ hardware. NI-DAQ is not packaged with signal
conditioning or accessory products. 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 (timed D/A
conversion), digital I/O, counter/timer operations, SCXI, RTSI,
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 DAQ 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 DAQ device.
NI-DAQ does not sacrifice the performance of National Instruments
DAQ devices because it lets multiple devices operate at their peak
performance.

Chapter 1 Introduction

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. Whether you are using
conventional programming languages, LabVIEW, or
LabWindows/CVI, your application uses the NI-DAQ driver software,
as illustrated in Figure 1-1.



National Instruments Corporation 1-3 PC-LPM-16/PnP User Manual

Chapter 1 Introduction

Conventional 

Programming Environment

(PC, Macintosh, or 

Sun SPARCstation)



DAQ or

SCXI Hardware

Figure 1-1.

Register-Level Programming

The final option for programming any National Instruments DAQ
hardware is to write register-level software. Writing register-level
programming software can be very time-consuming and inefficient and
is not recommended for most users.

LabVIEW 

(PC, Macintosh, or 

Sun SPARCstation)

NI-DAQ

Driver Software

Computer or 

LabWindows/CVI

(PC or Sun 

SPARCstation)

Personal 

Workstation

The Relationship between the Programming Environment, NI-DAQ,

and Your Hardware

Even if you are an experienced register-level programmer, consider
using NI-DAQ, LabVIEW, or LabWindows/CVI to program your
National Instruments DAQ hardware. Using the NI-DAQ, LabVIEW, or
LabWindows/CVI software is as easy and as flexible as register-level
programming and can save weeks of development time.

PC-LPM-16/PnP User Manual 1-4

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National Instruments Corporation

Optional Equipment

National Instruments offers a variety of products to use with your
PC-LPM-16/PnP board, including cables, connector blocks, and other
accessories, as follows:

• Cables and cable assemblies, shielded and ribbon

• Connector blocks, shielded and unshielded with 50-pin screw
terminals

• SCXI modules and accessories for isolating, amplifying, exciting,
and multiplexing signals for relays and analog output. With SCXI
you can condition and acquire up to 3,072 channels.

• Low channel-count signal conditioning modules, boards, and
accessories, including conditioning for strain gauges and RTDs,
simultaneous sample-and-hold circuitry, and relays

For more specific information about these products, refer to your
National Instruments catalogue or call the office nearest you.

Custom Cables

Chapter 1 Introduction

National Instruments currently offers a cable termination accessory, the
CB-50, for use with the PC-LPM-16/PnP. This kit includes a
terminated, 50-conductor, flat ribbon cable and a connector block.
Signal input and output wires can be attached to screw terminals on the
connector block and connected to the PC-LPM-16/PnP I/O connector.

The CB-50 is useful for the initial prototyping of an application or in
situations where PC-LPM-16/PnP interconnections are frequently
changed. Once you develop a final field wiring scheme, however, you
may want to develop your own cable. This section contains information
and guidelines for the design of custom cables.

The PC-LPM-16/PnP I/O connector is a 50-pin, male, ribbon cable
header connector. The following list gives recommended part numbers
for use with your PC-LPM-16/PnP board:

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

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



National Instruments Corporation 1-5 PC-LPM-16/PnP User Manual

Chapter 1 Introduction

Unpacking

The mating connector for the PC-LPM-16/PnP 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 PC-LPM-16/PnP. 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 the standard ribbon cables (50-conductor, 28 AWG,

stranded) that can be used with these connectors:

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

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

Your PC-LPM-16/PnP 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.
install a damaged board into your computer.

•

Never

touch the exposed pins of connectors.

Do not

PC-LPM-16/PnP User Manual 1-6

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National Instruments Corporation

Chapter

Installation and
Configuration

This chapter describes the installation and configuration of the
PC-LPM-16PnP. For information on installing and configuring the
PC-LPM-16, a non-PnP board, refer to Appendix C,

PC-LPM-16 (Non-PnP) Board

Hardware Installation

You can install the PC-LPM-16PnP in any available expansion slot in
your computer. The following are general installation instructions, but
consult your computer user manual or technical reference manual for
specific instructions and warnings.

1. Turn off and unplug 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.

4. Insert the PC-LPM-16PnP board into any 8-bit or 16-bit slot. It may
be a tight fit, but

5. Screw the mounting bracket of the PC-LPM-16PnP board to the
back panel rail of the computer.

6. Replace the cover.

7. Plug in and turn on your computer.

.

do not force

2

Using Your

the board into place.

The PC-LPM-16PnP is installed.



National Instruments Corporation 2-1 PC-LPM-16/PnP User Manual

Chapter 2 Installation and Configuration

Software Installation

If you are using NI-DAQ, refer to your NI-DAQ release notes to install
your driver software. Find the installation section for your operating
system and follow the instructions given there.

If you are using LabVIEW, refer to your LabVIEW release notes to
install your application software. After you have installed LabVIEW,
refer to the NI-DAQ release notes and follow the instructions given
there for your operating system and LabVIEW.

If you are using LabWindows/CVI, refer to your LabWindows/CVI
release notes to install your application software. After you have
installed LabWindows/CVI, refer to the NI-DAQ release notes and
follow the instructions given there for your operating system and
LabWindows/CVI.

If you are a register-level programmer, refer to Appendix D

Level Programming,

Board Configuration

Plug and Play

The PC-LPM-16PnP is fully compatible with the industry-standard

Intel/Microsoft Plug and Play Specification version 1.0a. A Plug and

Play system arbitrates and assigns resources through software, freeing

you from manually setting switches and jumpers. These resources

include the board base I/O address and interrupt channels. Each

PC-LPM-16PnP is configured at the factory to request these resources

from the Plug and Play Configuration Manager.

The Configuration Manager receives all of the resource requests at

startup, compares the available resources to those requested, and

assigns the available resources as efficiently as possible to the Plug and

Play boards. Application software can query the Configuration

Manager to determine the resources assigned to each board without

your involvement. The Plug and Play software is installed as a device

driver or as an integral component of the computer BIOS.

for software configuration information

, Register­.

PC-LPM-16/PnP User Manual 2-2

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National Instruments Corporation

Chapter 2 Installation and Configuration

Base I/O Address and Interrupt Selection

You can configure your PC-LPM-16PnP to use base addresses in the
range of 100 to FFF0 hex. The PC-LPM-16PnP occupies 16 bytes of
address space and must be located on a 16-byte boundary. Therefore,
valid addresses include 100, 110, 120…, FFE0, FFF0 hex. This
selection is software-configured and does not require you to manually
change any settings on the board.

The PC-LPM-16PnP can use interrupt channels 3, 4, 5, 6, 7, and 9.
There are different ways to assign the base address to your board:

• For Windows 95, the base address and interrupt should be set
automatically. However, if you want to view or change these
settings, you can set the board resources using the

Manager

these can be changed in the
a. Click the right mouse button on

b. Select
c. Select
d. Select the
You can change address and interrupt settings on the

page.

• For Windows 3.10 or 3.11, you can use the NI-DAQ Configuration
Utility (formerly
standard configuration utility is present in the system, you will not
be able to modify the board resources.

• You can use a standard configuration utility like Intel ISA
Configuration Utility (ICU). ICU dynamically assigns the base
address to your board when you boot up the computer. You can also
lock the board resources when you use ICU. For additional
information on ICU, contact Intel Corporation for a copy of Plug
and Play Specification version 1.0a.

. Windows 95 will automatically allocate resources, but

Device Manager

My Computer

system properties.

Device Manager
Data Acquisition Devices

PC-LPM-16

WDAQCONF

.

.

.

) to assign the board resources. If a

:

Device

to bring up

Resources

Non-Plug and Play

To configure the non-Plug and Play PC-LPM-16 board, refer to
Appendix C,

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National Instruments Corporation 2-3 PC-LPM-16/PnP User Manual

Using Your PC-LPM-16 (Non-PnP) Board

.

Chapter

Theory of Operation

This chapter includes an overview of the PC-LPM-16PnP board and
explains the operation of each functional unit making up the board. This
chapter also explains the basic operation of the PC-LPM-16PnP
circuitry.

Functional Overview

The following are the major components making up the
PC-LPM-16PnP:

• PC I/O channel interface circuitry

• Analog input and data acquisition circuitry

• Digital I/O circuitry

• Timing I/O circuitry

You can execute data acquisition functions by using the analog input
circuitry and some of the timing I/O circuitry. The internal data and
control buses interconnect the components. The theory of operation for
each of these components is explained in the remainder of this chapter.

3

The block diagram in Figure 3-1 shows a functional overview of the
PC-LPM-16PnP.

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National Instruments Corporation 3-1 PC-LPM-16/PnP User Manual

Chapter 3 Theory of Operation

PC I/O

Channel

Interface

Plug and 

Play

1 MHz

PC I/O Channel

Interrupt
Interface

+12 V

-12 V -12 V
+5 V

256-Word

FIFO

OUT0

CLK0

MSM82C53

Digital

12-Bit

Sampling

ADC

A/D Timing

FROM A/D FIFO

I/O

Figure 3-1.

Buffer

OUT1 OUT1*

PC-LPM-16PnP Block Diagram

Input Mux

16-Channel

Single-Ended

Scanning Counter

GATE<0..2>

CLK<1..2>
OUT<0..2>

8
8

0.5 A

1.0 A

16

EXTCONV*

3
2
3

EXTINT*

+12 V

+5 V

I/O Connector

PC-LPM-16/PnP User Manual 3-2



National Instruments Corporation

PC I/O Channel Interface Circuitry

The PC I/O channel interface circuitry consists of an address bus, a data
bus, interrupt lines, and several control and support signals. The
components making up the PC-LPM-16PnP PC I/O channel interface
circuitry are shown in Figure 3-2.

Chapter 3 Theory of Operation

Address Bus

Control Lines

Data Bus

PC I/O Channel

IRQ

Plug and 

Play Circuitry

Timing

Interface

Data

Buffers

Plug and

Play Interrupt

Control

Figure 3-2.

PC I/O Interface Circuitry Block Diagram

Address

Decoder

Register Selects

Read & Write Signals

Internal Data Bus

Interrupt Requests

The circuitry consists of Plug and Play address decoders, data buffers,
I/O channel interface timing control circuitry, and interrupt control
circuitry. The circuitry monitors address lines SA4 through SA15 to
generate the board enable signal, and uses lines SA0 through SA3 plus
timing signals to generate the onboard register select signals and
read/write signals. The data buffers control the direction of data transfer
on the bidirectional data lines based on whether the transfer is a read or
write operation.

The interrupt control circuitry routes any enabled interrupts to the
selected interrupt request line. The PC-LPM-16PnP has six interrupt

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National Instruments Corporation 3-3 PC-LPM-16/PnP User Manual

Chapter 3 Theory of Operation

request lines available: IRQ3, IRQ4, IRQ5, IRQ6, IRQ7, and IRQ9.
The PC-LPM-16PnP generates interrupts in three different situations:

• When an A/D conversion generates data that can be read from FIFO

• When an active low-level signal is detected on the EXTINT* line

• When a rising-edge signal is detected on counter 2 output
The PC-LPM-16PnP individually enables and clears each one of these

interrupts. For more detailed information on generating interrupts
externally, see the EXTINTEN bit of the Command Register 1
description in Appendix D,

Register-Level Programming

Analog Input and Data Acquisition Circuitry

The PC-LPM-16PnP has 16 channels of analog input with 12-bit
A/D conversion. Using the timing circuitry, the PC-LPM-16PnP can
also automatically time multiple A/D conversions. Figure 3-3 shows a
block diagram of the analog input and data acquisition circuitry.

.

PC I/O 

Channel 

Interface

Interrupt 

PC I/O Channel

Interface

1 MHz

PC-LPM-16/PnP User Manual 3-4

8

A/D RD

CONVAVAIL

CLK0

256-Word

FIFO

MSM82C53

Figure 3-3.

A/D

Data

OUT0

Analog Input and Data Acquisition Circuitry Block Diagram

12-Bit 

Sampling 

ADC

A/D Timing

Buffer

Input Mux 

16-Channel 

Single-Ended

Scanning Counter

EXTCONV*



National Instruments Corporation

16

ACH<0..15>

4

I/O Connector

Analog Input Circuitry

The analog input circuitry consists of an input multiplexer, a jumper­selectable gain stage, and a 12-bit sampling ADC. The 12-bit output is
sign-extended to 16 bits before it is stored in a 256-word deep FIFO
memory.

The input multiplexer stage is made up of a CMOS analog input
multiplexer and has 16 analog input channels (channels 0 through 15).
With the input multiplexer stage, input overvoltage protection of ±45 V
is available powered on, or ±35 V powered off.

The PC-LPM-16PnP uses a successive-approximation analog-to-digital
converter (ADC). Software-selectable gains of 0.5, 1, and 2 for the
input signal combined with the ADC’s fixed input range of ±5 V yield
four useful analog input signal ranges, 0 to 10 V, ±5 V, 0 to 5 V, and

±

2.5 V.

When an A/D conversion is complete, the ADC clocks the result into
the A/D FIFO. The A/D FIFO is 16 bits wide and 256 words deep. This
FIFO serves as a buffer to the ADC and has two benefits. First, any time
an A/D conversion is complete, the A/D FIFO saves the value for later
reading, and the ADC can start a new conversion. Secondly, the A/D
FIFO can collect up to 256 A/D conversion values before losing any
information, thus giving the software some extra time (256 times the
sample interval) to catch up with the hardware. If the A/D FIFO stores
more than 256 values without the A/D FIFO being read, an error
condition called A/D FIFO Overflow occurs and A/D conversion
information is lost.

Chapter 3 Theory of Operation

The A/D FIFO generates a signal that indicates when it contains
conversion data. You can read the signal state from the PC-LPM-16PnP
Status Register 1.

The output from the ADC is in two’s complement format. In unipolar
input mode (0 to 10 V or 0 to 5 V input range configuration), the data
from the ADC is interpreted as a 12-bit positive number ranging from 0
to 4,095. In bipolar input mode (±5 or ±2.5 V input range
configuration), the data from the ADC is interpreted as a two’s
complement number ranging from -2,048 to +2047. The ADC’s output
is always sign-extended to 16 bits by board circuitry so that data values
read from the FIFO are 16 bits wide.

The ADC on the PC-LPM-16PnP includes calibration circuitry that
makes it possible to minimize zero, full-scale, and linearity errors. The

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National Instruments Corporation 3-5 PC-LPM-16/PnP User Manual

Chapter 3 Theory of Operation

ADC goes through a self-calibration cycle under software control. To
properly use this ADC auto-calibration feature, you need an accurate
input stage that does not introduce significant offset and gain errors.
The analog input stage on the PC-LPM-16PnP maintains the required
accuracy without trimpot adjustments.

Data Acquisition Timing Circuitry

A data acquisition operation refers to the process of carefully timing the
interval between successive A/D conversions. This interval is called the

sample interval

various clocks and timing signals that perform this timing. The
PC-LPM-16PnP can perform two types of data acquisition: single­channel data acquisition and multichannel scanning data acquisition.
Multichannel scanning data acquisition uses a counter to automatically
switch between analog input channels during a data acquisition
operation.

Data acquisition timing consists of signals that initiate a data
acquisition operation and generate scanning clocks. Sources for these
signals are supplied mainly by timers on the PC-LPM-16PnP board.
One of the three counters of the onboard MSM82C53 is reserved for this
purpose.

. The data acquisition timing circuitry consists of

You can initiate an A/D conversion by a falling edge on the counter 0
output (OUT0) of the MSM82C53 onboard counter/timer chip, or by a
rising edge on EXTCONV* input.

The sample-interval timer is a 16-bit down-counter that uses the
onboard 1 MHz clock to generate sample intervals from 20 to 65,535 µs
(see

Timing I/O Circuitry

information). Each time the sample-interval timer reaches zero, it
generates a pulse and reloads with the programmed sample-interval
count. This operation continues until you reprogram the counter.

As stated in Appendix D,
is required for data acquisition operations. The software must keep
track of the number of conversions that have occurred and turn off
counter 0 after it receives the required number of conversions.

PC-LPM-16/PnP User Manual 3-6

later in this chapter for more timing

Register-Level Programming



National Instruments Corporation

, only counter 0

Chapter 3 Theory of Operation

Single-Channel Data Acquisition

During single-channel data acquisition, the channel-select bits in
Command Register 1 select the analog input channel before data
acquisition begins. This multiplexer setting remains constant during the
entire data acquisition process; therefore, all A/D conversion data is
read from a single channel.

Multichannel Scanning Data Acquisition

Multichannel data acquisition is performed when you enable scanned
data acquisition. A scan counter on the board controls multichannel
scanning.

For multichannel scanning operations, the scan counter decrements
from the highest channel which you select through channel 0. Thus, the
board can scan any number of channels from 2 to 16. Notice that the
same analog input range is used for all channels in the scan sequence.

Data Acquisition Rates

The maximum data acquisition rate (number of samples per second) is
determined by the conversion period of the ADC plus the acquisition
time of its track-and-hold stage. During multichannel scanning, the
settling time of the input multiplexers and operational amplifier further
limits the data acquisition rate. After the input multiplexers switch
channels, the amplifier must be able to settle to the new input signal
value to within 12-bit accuracy before performing an A/D conversion,
or else it will not achieve 12-bit accuracy. The maximum data
acquisition rate for both single-channel and multichannel operation is
50 kS/s. The signal will settle to ±1 LSB for any range if you do not
exceed a signal sampling frequency of 50 kS/s. If you exceed the
recommended data acquisition rate, the analog input circuitry may not
perform at 12-bit accuracy. If you exceed this rate, an error condition
called

overrun

occurs and you will lose some conversion data.

This recommended rate of 50 kS/s assumes that voltage levels on all the
channels included in the scan sequence are within range and are driven
by low-impedance sources. Signal levels outside the ranges on the
channels included in the scan sequence adversely affect the input
settling time. Similarly, channels driven by high-impedance signal
sources should be allowed for greater settling time.



National Instruments Corporation 3-7 PC-LPM-16/PnP User Manual

Chapter 3 Theory of Operation

Digital I/O Circuitry

The PC-LPM-16PnP has 16 digital I/O lines that are TTL-compatible.
Pins DIN<0..7> of the I/O connector are digital input lines, and pins
DOUT<0..7> are digital output lines. These lines are monitored or
driven by the Digital Input Register or the Digital Output Register,
respectively. Reading the Digital Input Register returns the current state
of the DIN<0..7> lines. Writing to the Digital Output Register drives
the new value onto the DOUT<0..7> lines. The external device may
drive the EXTINT* signal to indicate the readiness of data transfer.

8

/

I/O RD

8

/

I/O WR

PC I/O Channel

Figure 3-4.

Digital 

Input 

Register

Digital 
Output 

Register

Status

Register 1

Plug and

Play
Interrupt
Interface

8

/

8

/

EXTINT*

Digital I/O Circuitry Block Diagram

DIN <0..7>

DOUT<0..7>

I/O Connector

PC-LPM-16/PnP User Manual 3-8



National Instruments Corporation

Timing I/O Circuitry

The PC-LPM-16PnP uses an MSM82C53 Counter/Timer integrated
circuit for data acquisition timing and for general-purpose timing I/O
functions. Three counters on the circuit are available for general use,
but the board can use only one of them, counter 0, internally for data
acquisition timing. Figure 3-5 shows a block diagram of both groups of
timing I/O circuitry.

PC I/O Channel

CTR RD/WR

1 MHz

Clock

8

/

Data

OUT0

GATE0

CLK0

CLK1

GATE1

OUT1

CLK2

GATE2

OUT2

MSM82C53 

Counter/Timer

Chapter 3 Theory of Operation

A/D Conversion Logic






Plug and Play

Interrupt

Interface

OUT0



GATE0

CLK1

GATE1

OUT1

OUT1*

CLK2

GATE2

OUT2

I/O Connector

Figure 3-5.

Timing I/O Circuitry Block Diagram

The MSM82C53 contains three independent 16-bit counter/timers and
one 8-bit Mode Register. As shown in Figure 3-5, you can use counter 0
for data acquisition timing, and counters 1 and 2 are free for general use.
You can program all three counter/timers to operate in several useful
timing modes. The programming and operation of the MSM82C53 is
presented in detail both in Appendix B,
Appendix D,

Register-Level Programming

MSM82C53 Data Sheet

.

, and

The timebase for counter 0 uses a 1 MHz clock generated from an
onboard oscillator. You must externally supply the timebases for
counters 1 and 2 through the 50-pin I/O connector. Figure 3-6 diagrams
the 16-bit counters in the MSM82C53.



National Instruments Corporation 3-9 PC-LPM-16/PnP User Manual

Chapter 3 Theory of Operation

CLK

GATE

Figure 3-6.

Counter

Counter Block Diagram

OUT

Each counter has a clock input pin, a gate input pin, and an output pin
labeled CLK, GATE, and OUT, respectively. The MSM82C53 counters
are numbered zero through two, and their GATE, CLK, and OUT pins
are labeled GATEN, CLKN, and OUTN, where N is the counter number.

PC-LPM-16/PnP User Manual 3-10



National Instruments Corporation