National Instruments Measure Data Acquisition User Manual

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Data Acquisition

User Manual

August 1996 Edition

Part Number 321004B-01

© Copyright 1995,1996 National Instruments Corporation.

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reader should consult National Instruments if errors are suspected. In no event shall National Instruments be liable for
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WARNING REGARDING MEDICAL AND CLINICAL USE

OF NATIONAL INSTRUMENTS PRODUCTS

National Instruments products are not designed with components and testing intended to ensure a level of reliability
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About This Manual

Organization of This Manual
Conventions Used in This Manual
Customer Communication xi

Chapter 1

Introduction

Using Measure with Your DAQ Device
DAQ Device Overview
Installing Measure

Manually Adding or Removing the DAQ Add-In

Uninstalling Measure

Chapter 2

Getting Started with Data Acquisition Tasks

Selecting a Data Acquisition Task
Configuring an Analog Input Task
Configuring an Analog Output Task
Adding Tasks to the DAQ Menu
Saving Tasks
Managing Tasks in a Workbook

Chapter 3

Using SCXI with Measure DAQ

SCXI Operating Modes

SCXI Analog Input
Multiple SCXI Modules and Chassis
SCXI Analog Output

© National Instruments Corporation v Measure Data Acquisition User Manual

Table of Contents

Chapter 4

Analog Input Reference

DAQ Device Overview
Analog Input Configuration Overview

Analog Input Scan List

Channels
High Limit
Low Limit

Scan Information

Number of scans
Scale to volts

Timing Settings

Scans/second
External scan clock

Display

At cell
In Columns

In Rows
Trigger Reference
Mode Reference
Advanced Timing Settings

Chapter 5

Analog Output Reference

Analog Output Configuration Overview
Advanced Configuration

Chapter 6

Using Measure Data Acquisition Tasks with VBA

Function Reference

DAQ
GetDAQErrorMessage

Appendix A

DAQ Hardware Capabilities

SCXI Information
MIO and AI Device Hardware Capabilities

Lab and 1200 Series and Portable Devices Hardware Capabilities
SCXI Module Hardware Capabilities
Analog Output Only Devices Hardware Capabilities

Measure Data Acquisition User Manual vi © National Instruments Corporation

Appendix B

Error Codes

Appendix C

Trouble Shooting

Appendix D

Customer Communication

Glossary

Index

Figures

Figure 1-1. Add-Ins Dialog Box

Figure 2-1. DAQ Tasks Dialog Box
Figure 2-2. Analog Input Configuration
Figure 2-3. Task Description Dialog Box
Figure 2-4. DAQ Tasks Dialog Box
Figure 2-5. Analog Output Configuration Dialog Box
Figure 2-6. DAQ Tasks Dialog Box
Figure 2-7. Adding Tasks to the DAQ Menu
Figure 2-8. The DAQ Menu
Figure 2-9. DAQ Tasks Dialog Box

Table of Contents

Figure 3-1. Selecting the Add>> button

Figure 4-1. Analog Input Configuration Dialog Box
Figure 4-2. Scan Clock and Channel Clock
Figure 4-3. Round Robin Scanning
Figure 4-4. Hardware Digital Trigger Dialog Box
Figure 4-5. Analog Input Mode Dialog Box
Figure 4-6. Advanced Timing Settings Option

Figure 5-1. Analog Output Configuration
Figure 5-2. Advanced Analog Output Configuration Dialog Box

© National Instruments Corporation vii Measure Data Acquisition User Manual

Table of Contents

Tables

Table 2-1. DAQ Tasks Dialog Box Options

Table 3-1. SCXI Channel Strings Syntax

Table 4-1. Examples of Valid Channel Strings
Table 4-2. Analog Input Configuration Buttons/Options
Table 4-3. Choices for Hardware Digital Trigger
Table 4-4. Choices for Analog Input Mode Dialog Box
Table 4-5. Choices for Advanced Timing
Table 5-1. Analog Output Configuration Reference
Table 5-2. Advanced Analog Output Configuration Options

Table A-1. Analog Input Configuration Programmability—MIO and AI Devices
Table A-2. Analog Input Characteristics—MIO and AI Devices (Part 1)
Table A-3. Analog Input Characteristics—MIO and AI Devices (Part 2)
Table A-4. Analog Output Characteristics—MIO and AI Devices
Table A-5. Analog Input Configuration Programmability—Lab,

1200 Series, Portable Devices
Table A-6. Analog Input Characteristics—Lab, 1200 Series, Portable Devices (Part 1)
Table A-7. Analog Input Characteristics—Lab, 1200 Series, Portable Devices (Part 2)
Table A-8. Analog Output Characteristics—Lab, 1200 Series, Portable Devices
Table A-9. Analog Input Characteristics—SCXI Modules
Table A-10. Terminal Block Selection Guide—SCXI Modules
Table A-11. Analog Output Characteristics—Analog Output Only Devices

Table B-1. Data Acquisition Error Codes

Measure Data Acquisition User Manual viii © National Instruments Corporation

The Measure Data Acquisition User Manual describes how to use the
Measure Data Acquisition Add-In with National Instruments data
acquisition boards to acquire data into Microsoft Excel. You should be
familiar with the operation of Microsoft Excel, your computer, your
computer’s operating system, and your data acquisition (DAQ) board.

Organization of This Manual

The Measure Data Acquisition User Manual is organized as follows.

• Chapter 1, Introduction, helps you install the Measure Data
Acquisition (DAQ) Add-In. You should have installed and
configured your DAQ hardware already.

• Chapter 2, Getting Started with Data Acquisition Tasks, contains a
tutorial for the following basic functions: Selecting a data
acquisition task, configuring an analog input task, configuring an
analog output task, adding tasks to the DAQ menu, saving tasks,
and managing tasks in a workbook.

• Chapter 3, Using SCXI with Measure DAQ, describes how to use
the Measure Data Acquisition Add-In in Excel with your Signal
Conditioning Extension for Instrumentation (SCXI) equipment.

• Chapter 4, Analog Input Reference, introduces some basic
concepts of data acquisition and contains a reference for analog
input configuration, hardware digital triggering, analog input
modes, and advanced timing. You should be familiar with the
hardware characteristics of your data acquisition device.

• Chapter 5, Analog Output Reference, introduces some concepts of
data acquisition and contains a reference for basic and advanced
Analog Output Configuration.

© National Instruments Corporation ix Measure Data Acquisition User Manual

About This Manual

• Chapter 6, Using Measure Data Acquisition Tasks with VBA,
describes how to run tasks from within Visual Basic for
Applications.

• Appendix A, DAQ Hardware Capabilities, contains SCXI
information and tables that summarize the analog I/O capabilities
of National Instruments data acquisition devices you might use
with Measure for Windows.

• Appendix B, Error Codes, describes the errors that can occur
while using the Measure DAQ Add-In.

• Appendix C, Troubleshooting, describes solutions to problems that
you might encounter using the Measure DAQ Add-In.

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

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

• The Index contains an alphabetical list of key terms and topics in
this manual, including the page where you can find each one.

Conventions Used in This Manual

The following conventions are used in this manual.

bold Bold text denotes a parameter, or the introduction of menus, menu

items, or dialog box buttons or options.

italic Italic text denotes emphasis, a cross reference, or an introduction to a

key concept.

bold italic Bold italic text denotes a note, caution, or warning.

Measure Data Acquisition User Manual x © National Instruments Corporation

About This Manual

monospace

» The » symbol leads you through nested menu items, and dialog box

Note:

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

options to a final action. The sequence

Files»Page Setup»Options»Substitute Fonts

directs you to pull down the File menu, select the Page Setup item,
select Options, and finally select the Substitute Fonts option from the
last dialog box.

This icon to the left of bold italicized text denotes a note, which alerts
you to important information.

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 D, Customer Communication, at the end of this manual.

Related Documentation

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

•

NI-DAQ User Manual for PC Compatibles

© National Instruments Corporation xi Measure Data Acquisition User Manual

Introduction

This chapter helps you install the Measure Data Acquisition (DAQ)
Add-In. You should have installed and configured your DAQ hardware
already. If you have not done so, please refer to the NI-DAQ User
Manual for PC Compatibles that came with your device for
instructions on installation and configuration.

Using Measure with Your DAQ Device

Measure is designed to work with many different National Instruments
DAQ devices. Before you can use Measure, you must install and
configure your DAQ device and the NI-DAQ driver software that came
with your DAQ device. NI-DAQ is the low-level driver software that
controls your DAQ device. Measure is a higher-level software
development tool that communicates to your DAQ device through
NI-DAQ. Refer to the documentation that comes with your DAQ
device to learn how to install it properly.

Once you install your DAQ device, you must install and configure your
NI-DAQ driver software.

You use the NI-DAQ Configuration Utility (
up your DAQ device. For some DAQ devices, such as the E Series
boards, you do not have to configure many settings. For other devices,
you might be required to set jumpers or switches on your device to
configure it to work in your system. Refer to the documentation that
came with your DAQ device to install your NI-DAQ driver software
and run

© National Instruments Corporation 1-1 Measure Data Acquisition User Manual

WDAQCONF.EXE.

WDAQCONF.EXE

) to set

Chapter 1 Introduction

DAQ Device Overview

Measure is an easy-to-use spreadsheet interface for acquiring data with
a wide range of National Instruments DAQ devices. Because Measure
works with so many different devices, the functionality and
performance of the software often varies based on the particular DAQ
device you use. Although Measure senses the type of DAQ device you
are using, you might select options in the task configuration that are not
supported by your particular device. Measure notifies you when such a
conflict occurs when you close the configuration window, or when you
test the task you have defined. Make sure to test each task once you
define it.

The following pages contain a tutorial to show you how to use
Measure. Refer to the Managing Tasks in a Workbook section in
Chapter 2, Getting Started with Data Acquisition Tasks, for detailed
information on the analog input and output settings you can configure
with Measure.

Installing Measure

1. Insert the Measure for Windows diskette into a 3½ inch floppy
drive.

2. Select Start»Run from the taskbar in Windows 95 or File»Run
from the Program Manager in other versions of Windows.

3. Type

4. Select a location for the setup program to install Measure for

5. Deselect any Add-Ins that you do not want to install.

6. Select OK.

The setup program copies the program files and on-line help files to the
directory that you choose and creates a program group. Setup also
automatically configures Excel to load the DAQ Add-In when you
launch Excel.

Measure Data Acquisition User Manual 1-2 © National Instruments Corporation

A:\SETUP

select OK.

Windows.

in the box labeled Command Line, and then

Manually Adding or Removing the DAQ Add-In

To add the DAQ Add-In manually, complete the following steps.

1. Select Tools»Add-Ins.

2. In the Add-Ins dialog box, search the Add-Ins Available list box
for the Measure Data Acquisition Add-In entry. Click in the
checkbox next to the Measure Data Acquisition Add-In entry. If
you cannot find the entry, click the Browse button and look for

DAQ.XLA

To remove the DAQ Add-In manually, deselect the checkbox next to it,
shown in Figure 1-1. The next time you launch Excel, Excel will not
load the DAQ Add-In automatically.

in the directory where you installed Measure.

Chapter 1 Introduction

Figure 1-1

. Add-Ins Dialog Box

Uninstalling Measure

To uninstall Measure, remove both the Serial Add-In and the Data
Acquisition Add-In from the Add-Ins list in Excel. Double-click the
Uninstall icon in the Measure folder to remove Measure from your
computer.

© National Instruments Corporation 1-3 Measure Data Acquisition User Manual

Getting Started with

Data Acquisition Tasks

After you install and configure your hardware and install the Measure
Data Acquisition Add-In, you are ready to acquire data. This chapter
contains a tutorial for each of the following basic functions.

• Selecting a Data Acquisition task

• Configuring an Analog Input task

• Configuring an Analog Output task

• Adding tasks to the DAQ menu

• Saving tasks

• Managing tasks in a workbook

You only need to read the sections for the functions that you use in
your application.

Selecting a Data Acquisition Task

This section contains step-by-step instructions for configuring analog
input and output tasks with Measure. To configure tasks, complete the
following steps.

1. Launch Excel.

2. Select DAQ»Configure DAQ Task to display the DAQ Tasks
dialog box, shown in Figure 2-1.

© National Instruments Corporation 2-1 Measure Data Acquisition User Manual

Chapter 2 Getting Started with Data Acquisition Tasks

Figure 2-1

. DAQ Tasks Dialog Box

The DAQ Tasks dialog box manages the I/O operations, or tasks,
that you define with Measure. From this dialog box, you can create
new tasks, edit existing tasks, and run I/O tasks interactively to test
their operation.

3. Select a DAQ device from the Data acquisition device drop-down
listbox at the top of the dialog box. The list of devices available in
the drop-down listbox is taken from the devices that you have
configured. If you have not run the configuration utility yet, refer
to the documentation that came with your DAQ hardware.

4. Click on the AI button under the heading Create a task to display
the Analog Input Configuration dialog box, shown in figure 2-2.

Measure Data Acquisition User Manual 2-2 © National Instruments Corporation

Chapter 2 Getting Started with Data Acquisition Tasks

Figure 2-2.

Analog Input Configuration

Configuring an Analog Input Task

From the Analog Input Configuration dialog box, you can specify all
the parameters for an analog input operation. In the following steps,
you create a simple analog input task. Refer to Chapter 4, Analog Input
Reference, for more detailed information about the different options for
analog input.

1. The Analog Input Scan List at the top of the dialog box is where
you specify the input channels on your DAQ device from which
you would like to acquire data. For each input channel you add to
the scan list, you must specify a high and low voltage limit for the
signals that you read. Measure puts default values for your device
in the high and low limit fields. Measure uses these limits to
configure the gain settings on your DAQ device for maximum
measurement accuracy.

Type 0 in the Channel field and click on the Add>> button to
place the channel into your scan list.

2. In the Scan Information section of the dialog box, you specify how
many scans of your channel list are to be acquired. A scan is a
single measurement from each channel in your scan list. In this

© National Instruments Corporation 2-3 Measure Data Acquisition User Manual

Chapter 2 Getting Started with Data Acquisition Tasks

example in which there is only one channel specified, the number
of scans is equal to the number of points acquired from channel 0.
If you were to specify two channels in your channel list, 100 scans
would result in 200 points of data acquired (100 from each
channel).

100

Type

in the Number of Scans field.

3. The Scan Rate section of the dialog box is where you specify how
fast you would like to acquire the data. The default setting of 1000
scans per second means that you acquire a single point from each
channel in your channel list 1000 times per second.

1000

Type

in the Scans/second field.

4. The Display section of the dialog box is where you specify the
cells on your worksheet to contain the acquired data. You
manually can type in a spreadsheet address, such as
can highlight the input field and use your mouse to select an area
on the spreadsheet to place your acquired data. Measure begins
with the upper-left most cell in the range that you supply and
places the data in rows or columns from that point in the
worksheet.

$A$1

Type

to place the 100 elements of data in the first column of

your worksheet.

5. Type the name

Read Channel 0

$A$1

, or you

in the Task Name field.

6. Click on the Description button to add a description for your task
under development, shown in Figure 2-3. Type

points of data from channel 0

Acquire 100

in the Task

Description dialog box, and click on the OK button.
Now you have finished specifying your first Measure analog input

task.

Figure 2-3.

Measure Data Acquisition User Manual 2-4 © National Instruments Corporation

Task Description Dialog Box

Chapter 2 Getting Started with Data Acquisition Tasks

7. Click on the OK button to return to the DAQ Tasks dialog box,
shown in Figure 2-4. Notice that you now have a task named

Read Channel 0

description for this new task appears in the dialog box as well.

in your task list. Notice also that the

Figure 2-4.

8. Click on the Run button to execute the task. When the task
completes, there are 100 datapoints in column A of your
worksheet.

DAQ Tasks Dialog Box

Configuring an Analog Output Task

If your DAQ device has analog output channels, you can use Measure
to generate analog output signals based on values in your spreadsheet.
Analog output tasks operate exactly opposite of analog input tasks.
You specify an area on your worksheet that contains data values, and
Measure converts these values to voltages and outputs them through an
analog output channel of your DAQ device. For more information on
analog output tasks, refer to Chapter 5, Analog Output Reference.

© National Instruments Corporation 2-5 Measure Data Acquisition User Manual

Chapter 2 Getting Started with Data Acquisition Tasks

1. From the DAQ Task dialog box, select AO from the Create a task
section of the dialog box to display the Analog Output
Configuration dialog box, shown in Figure 2-5.

Figure 2-5.

Analog Output Configuration Dialog Box

2. Type 0 in the Channel input field.

3. Type

$A$1:$A$10

in the Data cells input field. You manually
can type this range, or highlight the input field and drag particular
areas of your worksheet to specify a cell range. This parameter
specifies which cell values are used as analog output values.

4. Click on the Add button.

5. Type 10 in the Number of iterations input field. The number of
iterations determines how many times Measure outputs the values
specified in the cell range. You can type a value of 0 in this field
for continuous output of the values.

6. Type

1000

in the Updates per second input field. As in acquiring
data, you must specify an update rate to determine how fast the
data outputs through the analog output channel.

7. Type

8. Click on the Description button, and type

Output 10 iterations

in the Task Name input field.

Output 10

iterations of data on analog output Channel 0

for the description of your analog output task. Click on the OK
button.

9. Now you have finished configuring your first Measure analog

output task. Click on the OK button to return to the DAQ Tasks

Measure Data Acquisition User Manual 2-6 © National Instruments Corporation

Chapter 2 Getting Started with Data Acquisition Tasks

dialog box. Notice that your new analog output task appears in the
task list, shown in Figure 2-6.

Figure 2-6.

10. Highlight the

Run button to execute the analog output task. Make sure you have
valid voltage data in cells A1:A10 before running the task.

DAQ Tasks Dialog Box

Output 10 iterations

task and click on the

Adding Tasks to the DAQ Menu

Now that the two tasks are configured and tested from the DAQ Tasks
dialog box, you may want to make them more accessible from your
spreadsheet. With Measure, you can easily add these tasks to the DAQ
menu.

1. Select DAQ»Configure DAQ Tasks.

2. Click on the Edit Menu button to display the Edit DAQ Menu

dialog box, shown in Figure 2-7.

© National Instruments Corporation 2-7 Measure Data Acquisition User Manual

Chapter 2 Getting Started with Data Acquisition Tasks

Saving Tasks

Figure 2-7.

Adding Tasks to the DAQ Menu

3. Highlight each of the tasks in the window on the right and click on

the Add button to add them to the DAQ menu.

4. Click on the OK button to return to the Configure DAQ Tasks
menu. Click on the OK button to return to the Excel worksheet.

5. Pull down the DAQ menu. Notice that two new entries now appear
in the DAQ menu, shown in Figure 2-8. Now you can select these
tasks and execute them from the worksheet without going into the
Measure dialog boxes.

Figure 2-8.

The DAQ Menu

Each of your tasks are stored in your workbook automatically when
you click on the OK button in the DAQ Tasks dialog box. If you
configure a new task, but click on the Cancel button from the DAQ
Tasks dialog box, Measure does not store your new task in your
workbook.

Measure Data Acquisition User Manual 2-8 © National Instruments Corporation

Chapter 2 Getting Started with Data Acquisition Tasks

Your tasks are saved as part of the Excel workbook. Each time you
launch Excel and open a workbook that contains Measure tasks, they
appear in the task list of the DAQ tasks dialog box.

Managing Tasks in a Workbook

This section describes how to use the DAQ Tasks dialog box, shown in
Figure 2-9, to manage the tasks in a workbook. You can open this
dialog box by selecting DAQ»ConfigureDAQTasks from the menu
bar.

Figure 2-9

© National Instruments Corporation 2-9 Measure Data Acquisition User Manual

. DAQ Tasks Dialog Box

Chapter 2 Getting Started with Data Acquisition Tasks

Table 2-1 contains a list of the DAQ Tasks dialog box options with
descriptions of their use.

Table 2-1.

DAQ Tasks Dialog Box Options

Option/Button Description

Data acquisition device Select the National Instrument data acquisition device for which you

want to create a task. Measure scans your NI-DAQ configuration for
installed devices and lists only those devices that Measure supports.

Data acquisition tasks Measure lists all the tasks that you have created for a data acquisition

device. Select a task if you wish to run, edit, or delete it.

Task Description Measure displays the description of the selected task. You can assign a

description to a task when you create or edit it.

Edit Menu Add or delete tasks from the DAQ menu.
AI Create an Analog Input task for the selected data acquisition device.
AO Create an Analog Output task for the selected data acquisition device.
Run Run the selected data acquisition task.
Edit Edit the selected data acquisition task.
Delete Delete the selected data acquisition task.
OK Store in the active workbook all the changes that you made (creation of

tasks, changes to existing tasks, deletions of tasks, additions or
deletions to the DAQ menu).

Cancel Ignore all the changes that you made (creation of tasks, changes to

existing tasks, deletions of tasks, additions or deletions to the DAQ
menu).

Measure Data Acquisition User Manual 2-10 © National Instruments Corporation

Using SCXI

with Measure DAQ

This chapter describes how to use the Measure data acquisition (DAQ)
Add-in in Excel with your Signal Conditioning Extension for
Instrumentation (SCXI) equipment.

SCXI is a set of modules and terminal blocks used as a signal condition
front-end for your data acquisition devices. These modules perform
tasks such as multiplexing large numbers of signals, amplifying low­level signals, providing isolation between your data acquisition devices
and transducers, and so on.

To use your SCXI modules with Measure, first you must configure all
your DAQ hardware using the NI-DAQ Configuration Utility

WDAQCONF.EXE

(
device number to each of your DAQ devices and define the
connections to your SCXI modules. In most cases, your DAQ device is
a plug-in board in your computer although it also can be a PC Card
(PCMCIA) format DAQCard or a SCXI-1200 module. You use the
DAQ devices for the actual A/D conversions of your analog input
signals, and for controlling SCXI modules. Each SCXI module is
controlled by one DAQ device, and is assigned as such in the
configuration utility. If you have any questions about the configuration
utility, consult the NI-DAQ User Manual for PC Compatibles.

). In the configuration utility, you must assign a

Once you have configured the SCXI system, using the Measure DAQ
Add-In is very similar to using a simple DAQ device. The only
difference in the operation is the use of the channel string in the scan
list to specify the channels on specific SCXI modules you want to
acquire. All other parameters of the DAQ Add-In operate the same.

SCXI Operating Modes

You can operate SCXI modules in two different modes-multiplexed
and parallel. In the multiplexed mode, all analog input channels for
each SCXI module are multiplexed (routed) onto one input channel of

© National Instruments Corporation 3-1 Measure Data Acquisition User Manual

Chapter 3 Using SCXI with Measure DAQ

your data acquisition device. The multiplexed mode is the default and
recommended mode to use with SCXI. In the parallel mode, each SCXI
module is directly connected to one data acquisition device and each
analog input channel on a SCXI module is connected to a separate
analog input channel on the data acquisition device. Not all data
acquisition devices or SCXI modules support the parallel mode.
Consult your data acquisition hardware user manual for more
information.

SCXI Analog Input

To configure channels on a SCXI analog input module in the DAQ task
configuration, first select the DAQ device in the main DAQ Tasks
dialog box to which the SCXI module is directly or indirectly
connected. Then, select the AI button to create an AI task or the Edit
button to modify an existing AI task. In the Analog Input
Configuration dialog box, specify the SCXI channel(s) you want to
acquire in the Channels field by entering a channel string. This channel
string provides information about the DAQ device channel, SCXI
chassis number, SCXI module number, and SCXI channel number. The
channel string has the following format:

ob0!scx!mdy!z

In the SCXI channel string, x represents the chassis number, y the
module number, and z the channel number.

ob0

‘

in the SCXI channel string indicates which onboard channel (on

’
the DAQ device) to use to acquire the data. In the SCXI multiplexed
mode (default mode), all SCXI channels from one SCXI chassis are
multiplexed onto one onboard channel. Usually, this is channel 0 (

ob0

in the SCXI string), unless you are using more than one SCXI chassis;
in which case each additional chassis uses the next onboard channel
(i.e. Chassis 2 uses onboard channel 1, and so on).

scx

represents the chassis number where x is replaced by the actual

‘

’
number (e.g.

sc1

). The chassis are numbered starting with 1 and the

chassis number is assigned in the NI-DAQ configuration utility.

mdy

represents the module number where y is replaced with the

‘

’
actual number (e.g.

md2

). The modules are numbered 1 through

n

on

each SCXI chassis with module 1 being in the left-most slot of the

n

SCXI chassis and module

Measure Data Acquisition User Manual 3-2 © National Instruments Corporation

in the right-most slot.

in the SCXI channel string represents the actual channel number

‘z’
(e.g. 3). Channels on the SCXI modules are numbered starting at zero.
You specify a range of channels on your SCXI modules by listing the
first and last channel separated with a colon (e.g.

You only use the SCXI channel string when the SCXI is operating in
multiplexed mode and channels are multiplexed onto one or more
channels of the data acquisition device. In parallel mode, specify the
channel of your data acquisition device to acquire. Each channel on
your DAQ device is mapped in hardware to one channel on a SCXI
module in parallel mode.

Multiple SCXI Modules and Chassis

In the scan list of your DAQ AI task, you can specify channels from
multiple SCXI modules or chassis by adding multiple entries to the
scan list. Repeat the Add operation for each SCXI module. However,
you can specify only one group of consecutive channels per SCXI
module in the scan list. You must specify consecutive channels in an
incremental order (e.g.

ob0!sc1!md2!10:19

channel setting would be listed as follows. The two lines in the scan list
on the right are added separately by twice filling in the channel field on
the left and clicking on the
Figure 3-1.

Chapter 3 Using SCXI with Measure DAQ

).

0:5

ob0!sc1!md1!0:5,

). In the Measure DAQ Task Dialog Box, the

button, as shown in

Add>>

© National Instruments Corporation 3-3 Measure Data Acquisition User Manual

Chapter 3 Using SCXI with Measure DAQ

Figure 3-1

. Selecting the

Add>>

button

Table 3-1 lists other possible combinations for SCXI channel strings.

Table 3-1

. SCXI Channel Strings Syntax

String Syntax Description

ob0!sc1!md2!5

Channel 5 on module 2 of SCXI
chassis 1 is read through onboard
channel 0.

ob0!sc1!md2!0:7
ob0!sc1!md4!5:12

Channels 0-7 on module 2 and
channels 5-12 on module 4 of chassis
1 are read through onboard channel 0.

ob0!sc1!md3!3:4
ob1!sc2!md1!20:24

Channels 3 and 4 of module 3 of
chassis 1 are read through onboard
channel 0, and channels 20-24 of
module 1 on chassis 2 are read
through onboard channel 1.

In the parallel mode, each analog input SCXI module is connected
directly to a DAQ device and you must specify the channels of your
DAQ device in the channel list, not the SCXI channel string.

Note: The SCXI-1200 does not support the parallel mode with other SCXI

modules.

Measure Data Acquisition User Manual 3-4 © National Instruments Corporation

SCXI Analog Output

Chapter 3 Using SCXI with Measure DAQ

The current version of Measure does not support the use of analog
output (AO) channels on the SCXI-1124 module. You can use the
analog output channels of the SCXI-1200 module by selecting the
device number and the AO channel number as you would with any
other DAQ device.

© National Instruments Corporation 3-5 Measure Data Acquisition User Manual

Analog Input Reference

This chapter introduces some basic concepts of data acquisition and
contains a reference for analog input configuration, hardware digital
triggering, analog input modes, and advanced timing. You should be
familiar with the hardware capabilities of your data acquisition device.

DAQ Device Overview

Measure works with a wide variety of National Instrument DAQ
devices. This chapter provides a technical overview and reference
information about using Measure for analog input operations. Many of
the parameters that you can set up with Measure vary depending on
your DAQ device. For example, DAQ devices vary in acquisition
speed which affects how fast you can acquire data using Measure. In
addition, some DAQ devices have more extensive triggering
capabilities than other DAQ devices. Measure does not disable any of
its options according to the selected DAQ device. When selecting
options which are not supported by a particular DAQ device, you get
an error message during configuration or testing. Refer to the
documentation included with your DAQ hardware to learn more about
the particular capabilities of your DAQ device.

© National Instruments Corporation 4-1 Measure Data Acquisition User Manual

Chapter 4 Analog Input Reference

Analog Input Configuration Overview

Select DAQ»Configure DAQ Tasks and then press the AI button to
open the Analog Input Configuration dialog box, shown in Figure 4-1.
The sections below describe the fields within the Analog Input
Configuration dialog box, and Table 4-2 explains the remaining
options at the bottom of the Analog Input Configuration dialog box.

Figure 4-1.

Analog Input Configuration Dialog Box

Analog Input Scan List

To configure an acquisition, first you must select the channels that you
want to scan by entering a channel string in the Channels field. A scan
is one acquisition or reading from each channel in the Analog Input
Scan List. The scan list can have multiple entries of one or more
channels. Each entry has its own set of high and low limits which
determines the gains on the channels in the entry.

Channels

Specify channels to add to the scan list. A channel string can consist of
a single channel, a list of channels delimited by commas, a range of
channels denoted by the first and last channel of the range separated by
a colon, or any combination of the previous three types of syntax. The
order that you specify the channels in your channel string from

Measure Data Acquisition User Manual 4-2 © National Instruments Corporation