DAQ VXI-SC-1102 User Manual

VXI-SC-1102 User Manual

32-Channel Multiplexer Amplifier Module

February 1997 Edition

Part Number 321385A-01

© Copyright 1997 National Instruments Corporation. All Rights Reserved.

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Important Information

Warranty

The VXI-SC-1102 is warranted agai nst defects in mater ials and workm anshi p fo r 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 per iod. This warrant y includes par ts and labor .

The media on which you receive National Instru ments software ar e warranted not to fail to execute pro grammi ng
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 warr ant that t he operatio n of the softwar e shall be uni nte rrupt ed or erro r 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. Natio nal Instrum ents wil l pay the shippin g
costs of returning to the owner par ts whi ch are cov ered by w arranty .

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 editi ons 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 docum ent or the in format ion contai ned in it.

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XCEPT AS SPECIFIED HEREIN

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

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

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shall not be liable for any delay in performan ce due to causes beyo nd it s reasonable cont rol. The warranty pr ovided
herein does not cover damages, defects, malf unctio ns, or s ervice fai lures caused by owne r’s fail ure to fol low the
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ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND

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ATIONAL INSTRUMENTS

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LabVIEW®, NI-DAQ®, RTSI®, ComponentWorks™, CVI™, Measure™, SCXI™, and VirtualBench™ are
trademarks of Nationa l Ins trumen ts C orpor atio n.

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 design ed with comp onents and testing in tend ed to ensure a level o f reliabi lity
suitable for use in treatment and diag nosi s of humans . Appli cations of Nationa l Inst rument s prod ucts inv olving
medical or clinical treatment can create a potential for accidental injury caused by product failure, or by err ors on the
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monitor or safegua rd huma n he alth and sa fety in med ical or clin ical t reat ment .

About This Manual

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

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

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

Customer Communication............................................................................................xi

Chapter 1
Introduction

About the VXI-SC-1102...............................................................................................1-2

What You Need to Get Started.....................................................................................1-3

Software Programming Choices...................................................................................1-3

National Instruments Application Software...................................................1-3

NI-DAQ Driver Software...............................................................................1-4

VXIplug&play Instrument Driver..................................................................1-5

Optional Equipment......................................................................................................1-6

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

Table

of

Contents

Chapter 2
Installation

Current-Loop Receivers................................................................................................2-3

Installing Your Hardware .............................................................................................2-4

Chapter 3
Signal Connections

Front Connector............................................................................................................3-1

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

Channel Input Signal Connections.................................................................3-3

Ground-Referencing Your Signals...................................................3-4

Cold-Junction Sensor Connection..................................................................3-6

© National Instruments Corporation v VXI-SC-1102 User Manual

Table of Contents

Chapter 4
Theory of Operation

Functional Overview....................................................................................................4-1

VXIbus Interface.......................................................................................................... 4-2

Digital Control Circuitry.............................................................................................. 4-2

Analog Circuitry........................................................................................................... 4-3

Analog Input Channels...................................................................................4-3

Analog Output................................................................................................ 4-3

Chapter 5
Calibration

Calibration Equipment Requirements................................................. .........................5-1

Gain and Offset Calibration................................................................. ...... ...... ............. 5-2

Sample Program for Calibration...................................................................................5-4

Appendix A
Specifications

Appendix B
Customer Communication

Glossary

Index

Figures

Figure 1-1. VXI Signal Conditioning System.......................................................... 1-1

Figure 1-2. The Relationship between the Programming Environment, Your

Instrument Driver, and Your VXI-DAQ Hardware .............................. 1-5

Figure 2-1. VXI-SC-1102 Parts Locator Diagram...................................................2-2

Figure 2-2. Bent and Trimmed Resistor................................................................... 2-3

Figure 3-1. VXI-SC-1102 Front Connector Pin Assignments................................. 3-2

Figure 3-2. Ground-Referenced Signal Connection.................................................3-5

Figure 3-3. Floating Signal Connection Referenced to Chassis Ground................. 3-6

VXI-SC-1102 User Manual vi © National Instruments Corporation

Tables

Table of Contents

Figure 4-1. VXI-SC-1102 Block Diagram...............................................................4-1

Figure 5-1. Analog Bus Receptacle Pin Assignment ...............................................5-2

Table 3-1. Front Connector Signal Descriptions.....................................................3-3

© National Instruments Corporation vii VXI-SC-1102 User Manual

This manual des cribe s the el ectri cal an d mech an ical a spect s of the
VXI-SC-1102 and contains informat io n concerning its installation and
operation. The VXI-SC-1102 is a signal conditioning submodule in the
VXI-data acquisition (VXI-DAQ) line of National Instruments
products. The VXI-SC-1102 is designed for signa l conditionin g of
thermocouples, volt and m illivolt sour c es, and 4 to 2 0 mA source s o r
0 to 20 mA pr ocess- c urren t sou rc es. T he V XI- SC-1 102 has 32
differential analog input channels and one cold-junction sensor channel.

Organization of This Manual

The VXI-SC-1102 U se r Ma nual is organized as follows:

• Chapter 1, Introduction, d escribe s th e V XI-SC -11 02, lists wha t
you need to get started, optional software and optional e quipment,
and explains how to u npac k th e V XI-SC- 110 2.

• Chapter 2, Installation, describes how to install cu rrent- loop
receivers on your VXI-SC-1102 and gives inform ation about
installing your VXI-SC-1102 submodule into the VXI -SC-1000
carrier module.

• Chapter 3, Signal Connections, de scribes the input signal
connections to the VXI-S C-1102 sub module via the front
connector.

• Chapter 4, Theory of Operation, contains a functional overview of
the VXI-SC-1102 and e xpl ains the op era tion o f each func tional
unit.

• Chapter 5, Calibration, discusses the ca libration procedures for the
VXI-SC-1102.

• Appendix A, Specifications, lists the specifications for the
VXI-SC-1102.

• Appendix B, Customer Communication, co ntains form s y ou ca n
use to request help from National Instruments or to comment on our
products.

About

This

Manual

©

National Instruments Corporation ix VXI-SC-1102 User Manual

About This Manual

•The Glossary contains an alphabetical list and description of terms
used in this manual, including abbreviations, acronym s, metric
prefixes, mnemonics, symbols, an d general data acqu isition terms.

•The Index contains a n alpha betica l list o f ke y term s and topic s in
this manual, including the page whe re you can fin d ea ch on e.

Conventions Used in This Manual

The following conventions are used in this manual.

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

range of values assoc iated wit h a port, bit, or signal nam e (for exam ple,
ACH<0..7> stands for the signals ACH0 through ACH7).

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.

monospace Denotes text or characters that are to be literally input from the

keyboard, sections of c ode, p rogra mmin g exa m ples, a nd synt ax
examples. This fo nt is also use d for the prope r n ame s of d isk d rive s,
paths, directories, pro gra ms , subp rog rams, su bro utines, de vice n ames ,
functions, variables, filenames, and extensions, and for statements and

comments taken from program code.
PC Refers to the IBM PC/XT, the IBM PC AT, and compatible computers.
VXI-MIO module Refers to any of the N ationa l Instrum ents V XI- MIO Se ries of p lug-in

data acquisition boards.
carrier module Refers to the VXI-SC-1000, which plugs directly into a VXI slot and on

which VXI-SC submodules are installed.
VXI-SC submodule Refers to VXI signal conditioning hardware that installs onto the carrier

module.

Abbreviations, acronyms, me tric prefixes, mnemonics, symbols, an d

terms are listed in the Glossary.

VXI-SC-1102 User Manual x

©

National Instruments Corporation

National Instruments Documentation

The VXI-SC-1102 U se r Ma nual is one piece of the documenta tion set
for your VXI-DAQ s ystem . You co uld have any of seve ral type s of
documents, depending on the h ardw are and sof tware in yo ur syste m.
Use the different types of docu me nts you ha ve a s follow s:

• Your VXI-DAQ hardware user manuals—These manuals have
detailed information about the VXI-DAQ hardware that plugs into
or is connected to yo ur V XIbu s c hassis. Us e thes e ma nuals f or
hardware installation and configuration instructions, specification
information about your VXI-DAQ hardware, and application hints.

• Software documentation—You may have both application software
and driver software documentation. National Instruments
application software incl udes Com ponen tW ork s, LabV IEW,
LabWindows
Instruments driver software includes NI-DAQ and VXIplug&play
instrument drivers. After you set up y our ha rdw are system, use
either your application or driver softw are docume ntation to help
you write your application. I f you ha ve a lar ge, c omplica te d
system, it is worthwhile to look thr ough the software
documentation befo re yo u co nfigu re y our hard w are.

• Accessory installation guides or manuals—I f you are using
accessory products, read the terminal block and cable assembly
installation guides or accessory board user manuals. They explain
how to physically co nnec t the releva nt p ieces of the s ystem .
Consult these guides when you are mak ing your c onne ctions.

®

/CVI, Measure, and VirtualBench. National

About This Manual

Customer Communication

National Instruments wants to rece ive you r com ments o n ou r prod ucts
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 for ms are in
Appendix B, Customer Communication, at the end of this manual.

©

National Instruments Corporation xi VXI-SC-1102 User Manual

Chapter

Introduction

This chapter describe s the VX I-SC -1102, lists wha t y ou need to get
started, optional soft w are and option al eq ui p m en t , an d explains ho w to
unpack the VXI-SC-1102.

The VXI-SC-1102 is part of the VXI signal conditioning system, which
consists of a carrier m odu le and o ne or m ore V XI sign al con ditioning
submodules or filler panels as shown in Figure 1-1.

2

1

4

3

5

To VXIbus

Chassis

6

8

1

9

1 Analog Bus Receptacle
2SCMPs
3 SCMP Socket

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National Instruments Corporation 1-13 VXI-SC-1102 User Manual

4 Address Switch
5 VXI-SC Subslot 1
6 VXI-SC Subslot 2

Figure 1-1.

7 VXI-SC Carrier Module
8 VXI-SC-1150 Submodule
9 VXI-SC Submodule

VXI Signal Conditioning System

7

Chapter 1 Introduction

The VXI-SC-1000 is a carrier module that installs into a slot in a
VXIbus chassis and is po pulated w ith one or tw o submod ules. T he
VXI-SC-1102 is a submodule that installs into VXI-SC subslots on a
VXI-SC-1000 carrier module.

Your VXI-SC-1000 ca rrier modu le is shipp ed w ith a filler pane l
installed in one of the submodule sites. This filler panel is necessary for
the attachment of the front panel, so you should leave it in place until
you are ready to install a VXI-SC submodule.

About the VXI-SC-1102

The VXI-SC-1102 is a submodule for the signal conditio ning of
thermocouples, low-bandwidth volt and millivolt sources, 4 to 20 mA
current sources, a nd 0 to 2 0 mA p roce ss-curr en t sourc es . The
VXI-SC-1102 has 32 diffe rential analog inp ut cha nnels a nd o ne
cold-junction sensor channel. On each channel, the VXI-SC-1102 has a
three-pole lowpass filter with a 2 Hz cutoff frequency to reject 60 Hz
noise. Each channel also has an amplifier with a selectable gain of 1 or

100. You can multiplex the VXI-SC-1102 inputs to a single output,
which drives a single V XI-MIO boa rd c hanne l.

The VXI-SC-1102 operates with full functionality with National
Instruments VXI-MIO modules. You can multiplex several
VXI-SC-1102 submodules an d oth er VX I signa l con ditioning
submodules into a single channel on the VXI-MIO module, greatly
increasing the number of analog input signals that you can digitize.

You can also use National Instruments terminal blocks, which have
screw terminals to which you attach the input signals for the
VXI-SC-1102. In addition, some of these terminal blocks have a
temperature sensor for thermocouple cold-junction compensation
(CJC). The VXI-SC-1102 multiplexes this cold-junction sensor with the
32 input channels during a h ardw are sc an . A N ational Instr uments
isothermal terminal block is recommende d for thermoc ouple
applications.

Detailed specifications of the VXI-SC-1102 ar e listed in Appendix A,
Specifications.

VXI-SC-1102 User Manual 1-14

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National Instruments Corporation

What You Need to Get Started

To set up and use y our VXI- SC-1 102 , you w ill need the follow ing
items:

❑ VXI-SC-1102 submodule

VXI-SC-1102 User Ma nua l

❑
❑ VXI-SC-1000 carrier module and documentation
❑ VXI-MIO module and documentation
❑ One of the following software packages and documentation:

ComponentWorks
LabVIEW for Windows
LabWindows/CVI fo r W indo ws
NI-DAQ for PC compatibles
VirtualBen ch
VXIplug&play instrumen t dr iver

Chapter 1 Introduction

❑ Your VXIbus system

Software Programming Choices

There are several op tions to choo se from whe n programm ing your
National Instruments VXI-DAQ hardw are. You c an use LabVIE W,
LabWindows/CVI, Comp one ntWorks, V irtu alBench, or o ther
application development enviro nments with eith er NI-DAQ or the
VXIplug&play instrument driver. Both NI-DAQ and the
VXIplug&play instrument driver access the VXI-DAQ hardware
through the VISA driver software.

National Instruments Application Software

LabVIEW features interactive graphics, a state-of-the-art user
interface, and a po werf ul g raphic al progr am ming langua ge. The
LabVIEW Data Acquisition VI L ibra r y, a se ries of V Is fo r using
LabVIEW with National Instruments DAQ hardware, is included with
LabVIEW. The LabVIEW D ata A cquisitio n VI Libr ar y is functiona lly
equivalent to the NI-DAQ software.

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National Instruments Corporation 1-15 VXI-SC-1102 User Manual

Chapter 1 Introduction

LabWindows/CVI features interactive graphics, a state-of-the-art user
interface, and uses th e ANSI standa rd C pr ogr am ming la nguage . The
LabWindows/CVI Data Ac quisition Lib rary, a se ries of fun ctions f or
using LabWindows/CVI with National Instruments DAQ hardware, is
included with the NI-DAQ software kit. The LabWindow s/CVI Data
Acquisition Library is functionally equivalent to the NI-D AQ sof twar e.

ComponentWorks con tains tools for data acq uisition and instr ument
control built on NI-DAQ driver softw are. Component Works provide s a
higher-level programming interface for building virtual instruments
through standard OLE controls and DLLs. With ComponentWorks, you
can use all of the configuration tools, resource management utilities,
and interactive control utilities included with NI-DAQ.

VirtualBench features VIs that combine DAQ products, software, and
your computer to create a standalone instrument with the added benefit
of the processing, display, and storage capabilities of your computer.
VirtualBench instruments lo ad and sa ve wav efor m data to disk in the
same forms that can be us ed in po pular sp readsh eet pr ogram s and wor d
processors.

Using LabVIEW, Lab Windo ws/C VI , Compon en tW ork s, or
VirtualBench software will greatly reduce the development time for
your data acquisition and control application.

NI-DAQ Driver Software

The NI-DAQ driver sof tware is included at no ch ar ge with all National
Instruments DAQ hardware. NI-DAQ is not packaged with accessory
products. NI-DAQ has an extensive library of functions that you can
call from your application progr amming environment. The s e functions
include routines for analog input (A/D conversion), buffered data
acquisition (high-speed A/ D c onver sion) , analog ou tput ( 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 DAQ I/O functions for maximum flexibility and
performance. Ex am ples of h igh- leve l func tions are stre aming data to
disk or acquiring a certain number of data po ints. An examp le of a
low-level function is writing directly to registers on the DAQ device.
NI-DAQ does not sacrifice the performance of National Instruments

VXI-SC-1102 User Manual 1-16

©

National Instruments Corporation

VXI

plug&play

Chapter 1 Introduction

DAQ devices because it lets multiple devices operate at their peak
performance.

NI-DAQ maintains a consistent software interface among its different
versions so that you can cha nge p latfo rms w ith minimal mo dific ations
to your code.

Instrument Driver

National Instruments distributes VXIplug&play instrument drivers free
of charge. VXIplug&play instrument drivers are one leve l above the
NI-DAQ device driver and contain high-lev el software function s whose
architecture is specified by the VXIplug&play Systems Alliance. The
VXIplug&play standards increase interoperability with other vendors,
and ensure that drivers are designed and presented in a consistent
fashion that facilitates ease of use. Refer to Figure 1-2 to see the
relationship between your software components.

ComponentWorks,

LabVIEW, LabWindows/CVI,

or VirtualBench

Figure 1-2.

The Relationship between the Programming Environment, Your

Instrument Driver, and Your VXI-DAQ Hardware

Other Application

Development Environments

VXI

plug&play

Instrument Driver

NI-DAQ Driver Software

VISA

VXI-DAQ Hardware

©

National Instruments Corporation 1-17 VXI-SC-1102 User Manual

Chapter 1 Introduction

Optional Equipment

National Instruments offers a v ari ety of pr oducts to u se with your
VXI-SC-1102 module, as follows:

• Terminal blocks and 96-pin cables that allow you to attach input
signals to your submodule

• SCXI Process Current Resistor Kit

For more specific information about these products, refer to your
National Instruments catalogue or c all the of fice near est you .

Unpacking

Your VXI-SC-1102 subm odule is sh ippe d in a n antistatic p acka ge to
prevent electrostatic damage to the submodule. Electrostatic discharge
can damage severa l com pon ents on the su bm odu le. To a vo id su ch
damage in handling the submodule, take the following prec autions.

• Ground yourself via a ground ing strap or by holdin g a grounded
object.

• Touch the antistatic package to a me tal part of your VXIbus chassis
before removing the su bmo dule from th e pa ck ag e.

• Remove the submodule from the package and inspect the
submodule for loose components or any othe r sign of damage .
Notify National Instruments if the module appears damaged in any
way. Do not install a damaged submodule into your VXIbus
chassis.

• Never touch the exposed pins of connectors.

VXI-SC-1102 User Manual 1-18

©

National Instruments Corporation

Chapter

Installation

2

This chapter describes how to install current-loop receivers on your
VXI-SC-1102 and gives information abou t installing your
VXI-SC-1102 submodu le into the VXI -SC-1000 c arrie r mod ule .

Refer to Figu re 2-1, VXI -SC-11 02 Parts Locator Di agram, for
information as you read the instructions in this chapter.

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National Instruments Corporation 2-19 VXI-SC-1102 User Manual