National Instruments 321906B-01 User Manual

Computer-Based
Instruments

NI 2501/2503 User Manual

24-Channel Two-Wire Multiplexer

NI 2501/2503 User Manual

July 1998 Edition

Part Number 321906B-01

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© Copyright 1998 National Instruments Corporation. All rights reserved.

Important Information

Warranty

The NI 2501 and NI 2503 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 durin g the warranty p eriod . T his w arran ty i nclu des part s an d labo r.

The media on which you receive National Instruments software are warranted not to fail to execute programming
instructions, due to defects in materials and work man ship, for a peri od of 90 d ays from da te o f sh ipm ent, as evi denced
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 noti ce of su ch defect s d uring th e warranty perio d.
National Instruments does not warrant that the op eration of t he soft ware shall b e uni nterrup ted or erro r free.

A Return Material Authorization (RMA) number must b e ob tain ed fro m th e facto ry an d clearl y mark ed on t he outsi de
of the package before any equipment wil l be accepted for warranty work. National Instruments will pay the shippi ng costs
of returning to the owner parts which are covered by warran ty.

National Instruments believes that the information in this manual is accurate. The document has been c arefully 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 th is do cume nt with ou t p rio r no ti ce to hold ers o f thi s ed itio n. The read er sh ou ld
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 docume nt o r th e in form ati on con tai ned in i t.

XCEPT AS SPECIFIED HEREIN

E

ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE
CUSTOMER
OR INCIDENTAL OR CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF

National Instruments will apply regardless of the form of action, wh ether in con tract or tort , incl udin g n egli gen ce.
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, malfuncti ons, or s ervice failur es caused by own er’s fai lure to fol low
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.

ATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS

. N

ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS

, N

Copyright

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.

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED

. C

. This limitation of the liability of

,

Trademarks

CVI™, LabVIEW™, NI-SWITCH™, and PXI™ are tra d e marks of National In st rume nts Co rporat io 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 designed with com ponent s and tes ting inten ded to ensure a l evel of reliab ilit y
suitable for use in treatment and diagnosis of humans. Applications of National Instruments products invol ving m edical
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 Instrum ents product s 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.

Compliance

FCC/DOC Radio Frequency Interference
Class A Compliance

This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance
with the instructions in this manual, may cause interference to radio and television reception. Classification
requirements are the same for the Federal Communications Commission (FCC) and the Canadian
Department of Communications (DOC). This equipment has been tested and found to comply with the
following two regulatory agencies:

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant
to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial environment. This equipment generates,
uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction
manual, may cause harmful interference to radio communications. Operation of this equipment in a
residential area is likely to cause harmful interference in which case the user will be required to correct the
interference at his own expense.

Notices to User: Changes or modifications not expressly approved by National Instruments could void

If necessary, consult National Instruments or an experienced radio/television technician for additional
suggestions. The following booklet prepared by the FCC may also be helpful: Interference to Home
Electronic Entertainment Equipment Handbook. This booklet is available from the U.S. Government
Printing Office, Washington, DC 20402.

the user’s authority to operate the equipment under the FCC Rules.
This device complies with the FCC rules only if used with shielded interface cables

of suitable quality and construction. National Instruments used such cables to test
this device and provides them for sale to the user. The use of inferior or nonshielded
interface cables could void the user’s authority to operate the equipment under the
FCC rules.

Canadian Department of Communications

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment
Regulations.

Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur
du Canada.

Conventions

The following conventions are used in this manual.

<> Angle brackets containing numbers separated by an elli psis r epresen t a

range of values associated with a port, bit, or signal name (for example,
CH<0..7> stands for the signals CH0 through CH7).

This icon to the left of bold italic ized text denotes a n ote, which alerts
you to important information.

!

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

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

This icon to the left of bold italic ized text denotes a ca ution, wh ich
advises you of precautions to take to avoid injury, data loss, or a
system crash.

This icon to the left of bold italicized text denotes a warning, which advises
you of precautions to take to avoid being electrically shocked.

to a key concept. This font also denotes text from which you supply the
appropriate word or value, as in CHx.

Contents

Chapter 1
Routing Signals with Your NI 2501/2503

About the NI 2501/2503 ................................................................................................1-1

Analog Bus......................................................................................................1-2

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

Cold-Junction Sensor Channel........................................................................1-3

NI 2501 Amplifier...........................................................................................1-3

Connecting Signals ........................................................................................................1-4

Front Connector...............................................................................................1-4

Contact Protection..........................................................................................................1-10

Terminal Blocks.............................................................................................................1-10

Software Choices...........................................................................................................1-10

NI-SWITCH Driver Software .........................................................................1-10

National Instruments Application Software....................................................1-11

Third Party Software .......................................................................................1-11

Chapter 2
NI 2501/2503 Operation

Functional Overview......................................................................................................2-1

Multiplexer.....................................................................................................................2-4

Two-Wire Mode..............................................................................................2-4

One-Wire Mode...............................................................................................2-4

Four-Wire Mode..............................................................................................2-5

Matrix Mode....................................................................................................2-5

Switch Control Circuitry................................................................................................2-5

Random Scanning..........................................................................................................2-5

PXI Interface..................................................................................................................2-6

Triggers............................................................................................................2-6

External Trigger Input.......................................................................2-6

Scanner Advanced.............................................................................2-7

Modes................................................................................................2-7

Initiating Scanning...........................................................................................2-8

Multicard Triggering.......................................................................................2-8

Appendix A
Specifications

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National Instruments Corporation vii NI 2501/2503 User Manual

Contents

Appendix B
Accessories

Appendix C
Customizing Your Card

Appendix D
Architecture Drawings

Appendix E
Common Questions

Appendix F
Customer Communication

Glossary

Index

Figures

Figure 1-1. Front Connector Pinout Assignments for Two-Wire Mode .................1-5

Figure 1-2. Front Connector Pinout Assignments for One-Wire Mode..................1-6

Figure 1-3. Front Connector Pinout Assignments for Four-Wire Mode.................1-7

Figure 1-4. Front Connector Pinout Assignments to Create a 6 x 4 Matrix............ 1-8

Figure 2-1. NI 2501 Module Block Diagram .......................................................... 2-2

Figure 2-2. NI 2503 Module Block Diagram ..........................................................2-3

Figure C-1. Bent and Trimmed Resistor..................................................................C-2

Figure D-1. NI 2501 Switch Architecture................................................................ D-2

Figure D-2. NI 2503 Switch Architecture................................................................ D-3

Tables

Table 1-1. Front Connector Signal Description ....................................................1-9

NI 2501/2503 User Manual viii

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National Instruments Corporation

Routing Signals with Your
NI2501/2503

This manual describes the electrical and mechanical aspects of the

NI2501 FET multiplexer and the NI2503 mechanical relay multiplexer

and contains information concerning their installation andoperation.

This manual uses the term NI2501/2503 whenever information applies

to both instruments.

About the NI2501/2503

This section summarizes the features and operation of the NI2501/2503

switch card. Refer to Chapter2, NI2501/2503 Operation, for more

complete details. In addition, refer to AppendixA, Specifications,

fordetailed specifications of the two switch cards.

The NI2501 is a FET switch card, and the NI2503 is an armature

relayswitch card. Each consists of a 24 x 1 two-wire multiplexer in

PXI/Compact PCI format. You can take advantage of the switch card’s

flexibility to handle a wide variety of test systems through the use of

various accessories and software configurations. You can use the National

Instruments NI-SWITCH software included with your kit to configure and

operate the NI2501/2503 switch card.

1

The NI2501/2503 can also operate as two 12 x 1 or four 6 x 1 two-wire

multiplexers. You can use software-configurable switches to configure

theswitch card as a 48 x 1 one-wire multiplexer for making large numbers

of common referenced measurements. In addition, the NI2501/2503 can

operate as a 12 x 1 four-wire multiplexer to handle resistive measurements,

such as thermistors or RTDs. Finally, you can use a National Instruments

TB-2606 terminal block to further configure the NI2501/2503 as a 6 x 4

two-wire matrix.

The Connecting Signals section of this chapter contains more information

on one-wire, two-wire, four-wire, and matrix configurations, and includes

diagrams of the pinout connections to make.

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National Instruments Corporation 1-1 NI 2501/2503 User Manual

Chapter 1 Routing Signals with Your NI 2501/2503

Refer to AppendixB, Accessories, for more information on terminal blocks
you can order from National Instruments.

You can also use multiple NI2501/2503 cards together to expand the size
of the multiplexer or matrix. For example, you can connect two cards to
create a 48 x 1 two-wire multiplexer or a 12 x 4 two-wire matrix.

Caution The maximum voltage is different for the NI2501 and NI2503 switch cards.

!

Ifyou intend to use more than one type of card, be sure you do not exceed the
maximum voltage of any card in your system. Refer to AppendixA, Specifications,
for information.

Analog Bus

The NI2501/2503 works with a four-wire analog bus. You connect the
analog bus to the switch card through its main front-panel connector.
Youcan use the analog bus to simplify connecting multiple cards to an
instrument such as a digital multimeter (DMM). This bus makes it possible
to create large systems using multiple switch cards.

For example, if you have two NI2501/2503 cards—or one of each—in two
adjacent slots, you can connect them through the analog bus and create a
48x1 two-wire multiplexer. With this flexibility, you keep the wiring of
the modules to a minimum while you create large switching solutions. In
such cases, the scanning architecture uses some of the PXI trigger lines for
synchronization and delivers full access to all of the scanning features for
the cards. The National Instruments software you receive with the
NI2501/2503 handles the complexity of programming the cards.

Triggers

Two triggers are used to handshake the NI2501/2503 switch with PXI
instruments or other external instruments. The Scanner Advanced trigger
indicates when the card has closed all the necessary switches for the next
scan and the switches have settled, or debounced. This trigger is typically
wired to a measurement device, such as a DMM, which is configured to
take a reading when it receives the trigger.

The External Trigger Input trigger is sourced by another instrument, such
as the DMM, and causes the NI2501/2503 to advance to the next entry
inthe scan list. The triggers can be routed to the front connector of the
NI2501/2503, to any of the PXI TTL triggers, or to the PXI star trigger. If
no external trigger input is available, you can have the software trigger the
NI2501/2503 to advance to the next entry in the scan list.

NI 2501/2503 User Manual 1-2

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National Instruments Corporation

Refer to Chapter 2, NI 2501/2503 Operation, for more inf o r mation on

triggers.

Cold-Junction Sensor Channel

For low-voltage measurements, such as those provided by thermocouples,

the NI 2503 has very low thermal offset—less than 2 µV—to ensure

accurate measurements. For cold-junction compensation when switching

thermocouples, the NI 2501/2503 has a dedicated channel for a

temperature sensor. The National Instruments TB-2605 and TBX-68S

terminal blocks both have onboard temperature sensors that connect to the

dedicated cold-junction sensor channel.

NI 2501 Amplifier

The NI 2501 has an amplifier with a gain of 1. This amplifier can be

switched in-line before the COM0 signal and the AB0 signal. The amplifier

helps to decrease the settling time of the FET switch. The amplifier’s

high impedance isolates the FET from the resistance, capacitance,

and inductance in the external wiring. This isolation decreases the

resistance/capacitance time constant seen by the FET, which improves

settling time.

Chapter 1 Routing Signals with Your NI 2501/2503

The amplifier has an offset that should be calibrated for more accurate

measurements. The calibration data can be stored into and retrieved from

the EEPROM on the board. The software you received with your switch

card includes API function calls to retrieve and store calibration data.

When the amplifier is used, the switch card becomes directional, where

CHx is for signal inputs and COM0 or AB0 are for signal outputs.

The NI 2501 also has an amplifier in the CJS0+ to COM0+ signal path.

This amplifier in the cold-junction sensor signal path is used to improve

settling time performance. It prevents the impedance of the cold-junction

sensor from increasing the settling time when switching the CJS channel.

As a result, when scanning thermocouples, the settling time for the

cold-junction sensor channel should be about the same as for the channels

with the thermocouples.

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National Instruments Corporation 1-3 NI 2501/2503 User Manual

Chapter 1 Routing Signals with Your NI 2501/2503

Connecting Signals

This section describes the signal connections to the NI 2501/2503 module
via the module front connector. This section also includes specifications
and connection instructions for the signals on the NI 2501/2503 module
connectors.

Caution

!

Static electricity is a major cause of component failure. To prevent damage to the
electrical components in the module, observe antistatic precautions whenever
removing a module from the chassis or whenever working on a module.

Front Connector

Warning

Any connections that exceed the maximum settings for the NI 2501/2503 can
result in an electrical shock hazard and damage to the NI 2501/2503 module and
any or all of the boards connected to the PXI backplane. National Instruments
is NOT liable for any damages or injuries resulting from exceeding maximum
voltage ratings. Refer to Appendix A, Specifications, for information.

The pinout assignments for the NI 2501/2503 front connecto r vary
depending on the wiring mode you use. The following four diagrams show
the pin assignments for two-wire mode, one-wire mode, four-wire mode,
and matrix mode, respectively. Two-wire mode is shown first because it is
the most common configuration. Table 1-1, following the diagrams,
describes the connector signals. For more information on the wiring modes,
refer to the Multiplexer section in Chapter 2, NI 2501/2503 Operation.

NI 2501/2503 User Manual 1-4

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National Instruments Corporation

Chapter 1 Routing Signals with Your NI 2501/2503

CJS0–

CH0–
CH1–
CH2–
CH3–
CH4–

CH5–
COM0–
COM1–

CH6–

CH7–

CH8–

1_WIRE_LO_REF

CH9–

CH10–
CH11–

AB0–

AB1–
CH12–
CH13–
CH14–
CH15–
CH16–
CH17–

COM2–
COM3–

+5 V

GND
CH18–
CH19–
CH20–
CH21–
CH22–
CH23–

1

34 68
33 67
32 66
31 65
30 64
29 63
28 62
27 61
26 60
25 59
24 58
23 57
22 56
21 55
20 54
19 53
18 52
17 51
16 50
15 49
14 48
13 47
12 46
11 45
10 44

943
842
741
640
539
438
337
236
135

CJS0+
CH0+
CH1+
CH2+
CH3+
CH4+
CH5+
COM0+
COM1+
CH6+

CH7+
CH8+

GND
CH9+
CH10+
CH11+
AB0+
AB1+
CH12+
CH13+
CH14+
CH15+
CH16+
CH17+
COM2+
COM3+
SCAN_ADV

EXT_TRIG_IN
CH18+
CH19+
CH20+
CH21+
CH22+
CH23+

1

not used in two-wire mode

Figure 1-1. Front Connector Pinout Assignments for Two-Wire Mode

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National Instruments Corporation 1-5 NI 2501/2503 User Manual

Chapter 1 Routing Signals with Your NI 2501/2503

CJS–

CH24
CH25
CH26
CH27
CH28
CH29

COM0–

COM1– (CH30–CH35)

CH30
CH31

CH32

1_WIRE_LO_REF

CH33
CH34

CH35

AB0–

AB1–

CH36
CH37

CH38
CH39
CH40

CH41
COM2– (CH36–CH41)
COM3– (CH42–CH48)

+5 V

GND
CH42
CH43
CH44
CH45
CH46
CH47

1

1

1

1
1

34 68
33 67
32 66
31 65
30 64
29 63
28 62
27 61
26 60
25 59
24 58
23 57
22 56
21 55
20 54
19 53
18 52
17 51
16 50
15 49
14 48
13 47
12 46
11 45
10 44

943
842
741
640
539
438
337
236
135

1

CJS+
CH0
CH1
CH2
CH3
CH4
CH5
COM0+
COM1+ (CH6–CH11)
CH6

CH7
CH8

GND
CH9
CH10
CH11
AB0+

1

AB1+
CH12
CH13
CH14
CH15
CH16
CH17
COM2+ (CH12–CH17)
COM3+ (CH18–CH23)
SCAN_ADV
EXT_TRIG_IN
CH18
CH19
CH20
CH21
CH22
CH23

1

1
1

1

not used in one-wire mode

Figure 1-2. Front Connector Pinout Assignments for One-Wire Mode

NI 2501/2503 User Manual 1-6

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National Instruments Corporation

Chapter 1 Routing Signals with Your NI 2501/2503

CJS–
CH0A–
CH1A–
CH2A–
CH3A–
CH4A–
CH5A–

COM0A–
COM1A–

CH6A–
CH7A–

CH8A–

1_WIRE_LO_REF

CH9A–

CH10A–
CH11A–

AB0A–

AB0B–
CH0B–
CH1B–
CH2B–
CH3B–
CH4B–
CH5B–

COM0B–
COM1B–

+5 V

GND
CH6B–
CH7B–
CH8B–
CH9B–

CH10B–
CH11B–

1

1

34 68
33 67
32 66
31 65
30 64
29 63
28 62
27 61
26 60
25 59
24 58
23 57
22 56
21 55
20 54
19 53
18 52
17 51
16 50
15 49
14 48
13 47
12 46
11 45
10 44

943
842
741
640
539
438
337
236
135

1

CJS+
CH0A+
CH1A+
CH2A+
CH3A+
CH4A+
CH5A+
COM0A+
COM1A+
CH6A+

CH7A+
CH8A+

GND
CH9A+
CH10A+
CH11A+
AB0A+
AB0B+
CH0B+
CH1B+
CH2B+
CH3B+
CH4B+
CH5B+
COM0B+
COM1B+
SCAN_ADV

EXT_TRIG_IN
CH6B+
CH7B+
CH8B+
CH9B+
CH10B+
CH11B+

1

not used in four-wire mode

Figure 1-3. Front Connector Pinout Assignments for Four-Wire Mode

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National Instruments Corporation 1-7 NI 2501/2503 User Manual

Chapter 1 Routing Signals with Your NI 2501/2503

CJS–
COL0–
COL1–
COL2–
COL3–
COL4–
COL5–

ROW0–
ROW1–

COL0–
COL1–

COL2–

1_WIRE_LO_REF

COL3–
COL4–

COL5–

AB0– (ROW0–)
AB1– (ROW2–)

COL0–
COL1–

COL2–
COL3–
COL4–
COL5–

ROW2–
ROW3–

+5 V

GND
COL0–
COL1–
COL2–
COL3–
COL4–
COL5–

1

1

34 68
33 67
32 66
31 65
30 64
29 63
28 62
27 61
26 60
25 59
24 58
23 57
22 56
21 55
20 54
19 53
18 52
17 51
16 50
15 49
14 48
13 47
12 46
11 45
10 44

943
842
741
640
539
438
337
236
135

1

CJS+
COL0+
COL1+
COL2+
COL3+
COL4+
COL5+
ROW0+
ROW1+
COL0+

COL1+
COL2+

GND
COL3+
COL4+
COL5+
AB0+ (ROW0+)
AB1+ (ROW2+)
COL0+
COL1+
COL2+
COL3+
COL4+
COL5+
ROW2+
ROW3+
SCAN_ADV

EXT_TRIG_IN
COL0+
COL1+
COL2+
COL3+
COL4+
COL5+

1

not used in matrix mode

Figure 1-4. Front Connector Pinout Assignments to Create a 6 x 4 Matrix

For matrix mode, connect all pins with the same name together external to
the switch card. The National Instruments TB-2606 terminal block
connects the necessary pins to create the 6 x 4 matrix.

NI 2501/2503 User Manual 1-8

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National Instruments Corporation

Chapter 1 Routing Signals with Your NI 2501/2503

Table 1-1. Front Connector Signal Description

Signal Name Type Description

+5 V Output +5 VDC Source—Powers the temperature sensor

on the terminal block. 0.2 mA of source protected
by a resettable poly fuse.

GND Output Ground
CJS± Input Cold-junction Temperature Sensor Input—

Connects to the temperature sensor of the
terminal block.

1_WIRE_LO_REF Input The common reference signal used in one-wire

mode.

EXT_TRIG_IN Input External Trigger Input—Trigger from an

instrument to advance the switch card to the
next scan entry.

SCAN_ADV Output Scanner Advanced—Trigger to an instrument

that indicated the switch card has advanced to
the next scan and relays are debounced.

CH<0..47> (one wire)
CH<0..23>± (two wire)
CH<0..11>A± (four wire)

Input/Output Channels—Where signals are connected to the

switch card. CHx+ and CHx– are switched
together.

CH<0..11>B± (four wire)
COM0± (one wire)

Input/Output Common—The common for each bank.

COM<0..3>± (two wire)
COM<0..1>A± (four wire)
COM<0..1>B± (four wire)

AB0± (one wire)
AB<0..1>± (two wire)

Input/Output Analog Bus—Used to wire multiple switch cards

to an instrument such as a DMM.

AB0A± (four wire)
AB0B± (four wire)

COL<0..5>± Input/Output Columns—Where signals are connected to the

switch card. The card behaves as a matrix when
proper external wiring is added.

ROW<0..3>± Input/Output Rows—Where signals are connected to the

switch card. In matrix configuration any row
can be connected to any column.

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National Instruments Corporation 1-9 NI 2501/2503 User Manual

Chapter 1 Routing Signals with Your NI 2501/2503

Contact Protection

Caution

!

When inductive loads are connected to the relays, a large counter electromotive
force may occur at relay switching time due to the energy stored in the inductive
load. These flyback voltages can severely damage the relay contacts and greatly
shorten the life of the relay.

It is best to limit flyback voltages at your inductive load by installing a flyback
diode for DC loads or a movistor for AC loads.

Terminal Blocks

Several terminal blocks with screw terminals are available for easy signal
connection to the NI 2501/2503 inputs. Refer to Appendix B, Accessories.

Software Choices

You have several options to choose from when programming your National
Instruments switch card. You can use the NI-SWITCH driver software, or
National Instruments application software.

NI-SWITCH Driver Software

The NI-SWITCH instrument driver is an Intelligent Virtual Instrument
(IVI) compliant instrument driver that is bundled with NI-SWITCH cards
at no cost.

NI-SWITCH features a set of operations and attributes that exercise all
the functionality of the switching hardware, including configuration,
opening/closing, and scanning. In addition, NI-SWITCH comes with
an interactive soft front panel and online documentation.

NI-SWITCH eliminates the need to understand complex register
programming and interrupt handling in the Microsoft operating systems,
and frees you to focus on creating your test system.

NI 2501/2503 User Manual 1-10

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National Instruments Corporation

Chapter 1 Routing Signals with Your NI 2501/2503

National Instruments 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. Using LabVIEW or LabWindows/CVI can
significantly reduce the development time for your data acquisition and
control application.

LabVIEW features interactive graphics, a state-of-the-art user interface,
and a powerful graphical programming language. The LabVIEW
NI-SWITCH VI Library, a series of virtual instruments (VIs) for using
LabVIEW with National Instruments switch hardware, is included with
the NI-SWITCH driver.

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

Third Party Software

The NI-SWITCH instrument driver also includes support files for
Microsoft Visual C++ and Microsoft Visual Basic. Please see the
NI-SWITCH readme file for version support information.

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National Instruments Corporation 1-11 NI 2501/2503 User Manual