National Instruments GPIB-232CV-A User Manual

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GPIB

GPIB-232CV-A User Manual

IEEE 488 RS-232 Converter

GPIB-232CV-A User Manual

November 1999 Edition

Part Number 370905A-01

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Worldwide Technical Support and Product Information

www.ni.com

National Instruments Corporate Headquarters

11500 North Mopac Expressway Austin, Texas 78759-3504 USA Tel: 512 794 0100

Worldwide Offices

Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20, Brazil 011 284 5011, Canada (Calgary) 403 274 9391, Canada (Ontario) 905 785 0085, Canada (Québec) 514 694 8521, China 0755 3904939, Denmark 45 76 26 00, Finland 09 725 725 11, France 01 48 14 24 24, Germany 089 741 31 30, Greece 30 1 42 96 427, Hong Kong 2645 3186, India 91805275406, Israel 03 6120092, Italy 02 413091, Japan 03 5472 2970, Korea 02 596 7456, Mexico (D.F.) 5 280 7625, Mexico (Monterrey) 8 357 7695, Netherlands 0348 433466, Norway 32 27 73 00, Poland 48 22 528 94 06, Portugal 351 1 726 9011, Singapore 2265886, Spain 91 640 0085, Sweden 08 587 895 00, Switzerland 056 200 51 51, Taiwan 02 2377 1200, United Kingdom 01635 523545

For further support information, see the Technical Support Resources appendix. To comment on the documentation, send e-mail to techpubs@ni.com

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Important Information

Warranty

The GPIB-232CV-A is warranted against defects in materials and wo rkm ans hip fo r a period of two y ears from t he 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. Th is warrant y in cludes 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 sh ipmen t, as evid enced b y receipt s o r other documentation. National Instruments will, at its op ti on , repair or repl ace soft ware me dia th at do not ex ecu te pr ogram mi ng 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 uni nterrup ted 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 warrant y.

National Instruments believes that the information in this document 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 withou t p rio r no ti ce to hold ers o f thi s ed itio n. The read er sh ou ld consul t National Instruments if errors are suspected. In no even t shall Nati on al Inst rum ents be l iable fo r any dama ges aris in g o ut of or related to this document or the information contained in it.

XCEPT AS SPECIFIED HEREIN

WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER

NSTRUMENTS 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

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 co ver d amag es, defects, malfunctions, or service failures caused by ow ner’s fai lu re t o foll ow th e Nation al Inst rum ent s in stal l ation, op erat i on, or maintenance instructions; owner’s modification of the pro du ct; ow ner’s abus e, m isus e, or negligent acts; and po wer failure or surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.

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

, 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 informatio n retriev al s ystem, o r t ran sl ating , in who le or i n p art, wit ho ut t he prior written consent of National Instruments Corporation.

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR

. C

. This limitation of the liability of National Instruments will

. N

ATIONAL

Trademarks

NAT4882™, National Instruments™, NI-488.2™, and ni.com™ are trademarks of National Instruments Corporation. Product and company names mentioned herein are trad emarks o r trad e name s of thei r respect ive compan ies .

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

(1) NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN.

(2) IN ANY APPLICATION, I NCLUDING THE ABOVE , RELIABILITY OF OP ERATION OF THE SOFT WARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY, COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DE VEL OP AN APPLICAT ION, INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH) SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRON IC SYSTE M DUE TO THE RISK OF SYSTEM FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH, THE USER OR APPLICATION DESIGNE R MU ST T AKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS' TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS, THE USER OR A PPLICATION DE SIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITAB ILITY OF NA TIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

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Compliance

FCC/Canada Radio Frequency Interference Compliance*

Determining FCC Class

The Federal Communications Commission (FCC) has rules to protect wireless communications from interference. The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrialcommercial locations only) or Class B (for use in residential or commercial locations). Depending on where it is operated, this product could be subject to restrictions in the FCC rules. (In Canada, the Department of Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.)

Digital electronics emit weak signals during normal operation that can affect radio, television, or other wireless products. By examining the product you purchased, you can determine the FCC Class and therefore which of the two FCC/DOC Warnings apply in the following sections. (Some products may not be labelled at all for FCC, if so the reader should then assume these are Class A devices.)

FCC Class A products only display a simple warning statement of one paragraph in length regarding interference and undesired operation. Most of our products are FCC Class A. The FCC rules have restrictions regarding the locations where FCC Class A products can be operated.

FCC Class B products display either a FCC ID code, starting with the letters EXN, or the FCC Class B compliance mark that appears as shown here on the right.

The curious reader can consult the FCC web site information.

FCC/DOC Warnings

This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the instructions in this manual and the CE Mark Declaration of Conformity**, 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).

Changes or modifications not expressly approved by National Instruments could void the user’s authority to operate the equipment under the FCC Rules.

Class A

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.

http://www.fcc.gov for more

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.

Class B

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful

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interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

Canadian Department of Communications

This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations. Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du

Canada.

European Union - Compliance to EEC Directives

Readers in the EU/EEC/EEA must refer to the Manufacturer's Declaration of Conformity (DoC) for information** pertaining to the CE Mark compliance scheme. The Manufacturer includes a DoC for most every hardware product except for those bought for OEMs, if also available from an original manufacturer that also markets in the EU, or where compliance is not required as for electrically benign apparatus or cables.

* Certain exemptions may apply in the USA, see FCC Rules §15.103 Exempted devices, and §15.105(c). Also

available in sections of CFR 47.

** The CE Mark Declaration of Conformity will contain important supplementary information and instructions for

the user or installer.

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About This Manual

Conventions ...................................................................................................................xi

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

Chapter 1 Introduction

GPIB-232CV-A Overview ............................................................................................1-1

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

Optional Equipment................................................ .......................................................1-2

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

GPIB-232CV-A Panels..................................................................................................1-3

AC Front Panel................................................................................................1-3

Top Panel.........................................................................................................1-4

Rear Panel........................................................................................................1-5

Side Panels.......................................................................................................1-6

RS-232 Connector.............................................................................1-7

GPIB Connector................................................................................1-8

Chapter 2 Configure and Install Your Hardware

Configure Your Hardware .............................................................................................2-1

Configure the GPIB-232CV-A Parameters.....................................................2-2

Configure the Serial Port Parameters..............................................................2-5

Install Your Hardware ...................................................................................................2-6

Step 1. Shut Down Your System .....................................................................2-6

Step 2. Verify That You Have a Null-Modem Serial Cable............................2-7

Step 3. Connect the Cables..............................................................................2-7

Step 4. Power on Your System and Switch on Your GPIB-232CV-A ...........2-8

Chapter 3 Operation of the GPIB-232CV-A

Choosing Between D Mode and C Mode Configuration...............................................3-1

When to Use D Mode......................................................................................3-1

When to Use C Mode......................................................................................3-2

D Mode Overview .........................................................................................................3-3

Data Transfers in D Mode...............................................................................3-3

Choosing a Serial Port Buffer Size..................................................................3-4

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Contents

Using the SRQ Feature ...................................................................................3-4

Conditions That Cause SRQ to be Asserted.....................................3-5

Maximizing Performance with SRQ ................................................3-5

GPIB-232CV-A Serial Poll Responses...........................................................3-6

GPIB-232CV-A Operation in Listen-Only Mode...........................................3-6

C Mode Overview .........................................................................................................3-7

Data Transfers in C Mode...............................................................................3-7

Modes of Operation Within C Mode ..............................................................3-8

Timeout Termination Mode..............................................................3-8

<CR> or <LF> Termination Mode ................................................... 3-9

No-Swap Mode.................................................................................3-10

Data Buffering and Handshaking Schemes...................................................................3-11

Hardware Handshaking ...................................................................................3-11

XON/XOFF Software Handshaking..................................... ..........................3-12

Appendix A Specifications

Appendix B Interfacing to a Serial Device

Appendix C Application Examples

Appendix D Technical Support Resources

Glossary

Index

Figures

Figure 1-1. GPIB-232CV-A AC Front Panel..........................................................1-3

Figure 1-2. GPIB-232CV-A Top Panel.............................. .....................................1-4

Figure 1-3. GPIB-232CV-A Rear Panel..................................................................1-5

Figure 1-4. Location of the Connectors and the DC Power Jack ............................ 1-6

Figure 1-5. RS-232 Connector and Signal Designations.........................................1-7

Figure 1-6. GPIB Connector and Signal Designations............................................1-8

GPIB-232CV-A User Manual viii www.ni.com

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Contents

Figure 2-1. Factory Default Switch Settings for SW1.............................................2-2

Figure 2-2. Factory Default Switch Settings for SW2.............................................2-5

Figure 3-1. Example of D Mode System Setup .......................................................3-2

Figure 3-2. Example of C Mode System Setup........................................................3-2

Figure 3-3. D Mode System Layout.........................................................................3-3

Figure 3-4. Switch Settings for Listen-Only Mode..................................................3-6

Figure 3-5. C Mode System Layout.........................................................................3-7

Figure 3-6. Timeout Termination Mode Cycle........................................................3-8

Figure B-1. Location of the RS-232 Connector........................................................B-3

Figure B-2. Cable Configuration for 9-pin DTE to 9-pin DCE

with Handshaking ..................................................................................B-4

Figure B-3. Cable Configuration for 9-pin DTE to 25-pin DCE

with Handshaking ..................................................................................B-4

Figure B-4. Minimum Configuration for 9-pin DTE to 9-pin DCE.........................B-5

Figure B-5. Minimum Configuration for 9-pin DTE to 25-pin DCE.......................B-5

Figure B-6. Cable Configuration for 9-pin DTE to 9-pin DTE

with Handshaking ..................................................................................B-7

Figure B-7. Cable Configuration for 9-pin DTE to 25-pin DTE

with Handshaking ..................................................................................B-7

Figure B-8. Minimum Configuration for 9-pin DTE to 9-pin DTE.........................B-8

Figure B-9. Minimum Configuration for 9-pin DTE to 25-pin DTE.......................B-8

Figure C-1. Example of Print Spooler Setup............................................................C-2

Tables

Table 1-1. LED Descriptions..................................................................................1-4

Table 2-1. Configuration Parameters for SW1 Switches 1 through 5 .................... 2-2

Table 2-2. Configuration Parameters for SW1 Switches 6 and 7...........................2-4

Table 2-3. Configuration Parameters for SW1 Switch 8........................................2-4

Table 2-4. Configuration Parameters for SW2 Switches 1 through 3 .................... 2-5

Table 2-5. Configuration Parameters for SW2 Switches 4 through 8 .................... 2-6

Table 2-6. National Instruments Null-Modem Serial Cables.................................2-7

Table B-1. RS-232 Serial Port Signal Configuration..............................................B-2

Table B-2. Cable Wiring Scheme for GPIB-232CV-A DTE to

Serial Device DCE ................................................................................B-3

Table B-3. Cable Wiring Scheme for GPIB-232CV-A DTE to

Serial Device DTE.................................................................................B-6

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About This Manual

The GPIB-232CV-A User Manual describes the features, functions, and operation of the GPIB-232CV-A. This manual assumes that you have a general knowledge of RS-232 serial communications and the General Purpose Interface Bus (GPIB).

Conventions

The following conventions appear in this manual: This icon denotes a caution, which advises you of precautions to take to

avoid injury, data loss, or a systemcrash.

bold Bold text denotes items that you must select or click on in the software,

such as menu items and dialog box options. Bold text also denotes parameter names.

IEEE 488 and IEEE 488 and IEEE 488.2 refer to the ANSI/IEEE Standard 488.1-1987 IEEE 488.2 and the ANSI/IEEE Standard 488.2-1992, respectively, which define the

GPIB.

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

to a key concept. This font also denotes text that is a placeholder for a word or value that you must supply.

monospace Text in this font denotes text or characters that you should enter 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 code excerpts.

RS-232 RS-232 refers to the ANSI/EIA-232-C standard.

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About This Manual

GPIB-232CV-A Overview

The GPIB-232CV-A has a powerful 8-bit microcomputer tailored for use as an IEEE 488-to-RS-232 protocol converter. Both the RS-232 serial port and the GPIB (IEEE 488) port are interrupt-driven and feature extremely fast response times to external data transfers. The GPIB-232CV-A can transparently convert data between the two ports so that control codes or special commands are not required. Data transfers in either direction are possible at all times.

The GPIB-232CV-A microprocessor contains an integrated direct memory access (DMA) controller for high-speed data transfers from the GPIB circuitry . The GPIB-232CV-A also increases the effic iency of the interface system by using a 256 KB RAM buf fer to isolate the slower de vice from the faster port. You can use the GPIB-232CV-A to interface either a GPIB Controller or a GPIB device to a computer or instrument with a RS-232 port. The RS-232 serial port is fully compatible with all electrical specifications in the RS-232 standard.

The operating system of the GPIB-232CV-A is contained in read-only memory (ROM) and can address up to 256 KB of dynamic random-access memory (RAM). The operating system programs and maintains the LSI GPIB Controller chip, the NAT4882, which implements all IEEE 488 interface functions. The GPIB-232CV-A microprocessor contains an integrated memory management unit, a dynamic RAM controller, a clock generator, a programmable timer unit, a full duplex UART (Universal Asynchronous Receiver Transmitter), and an interrupt controller.

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Chapter 1 Introduction

What You Need to Get Started

Before you install your GPIB hardware, make sure you have all of the following items:

❑ One of the following boxes, which is included in your kit:

– GPIB-232CV-A (100-120 VAC) – GPIB-232CV-A (220-240 VAC) – GPIB-232CV-A (DC)

❑ If you have the GPIB-232CV-A AC version, one of the following

power cords: – U.S. standard power cord – Swiss power cord – Australian power cord – Universal European power cord – North American power cord – U.K. power cord

❑ If you have the GPIB-232CV-A DC version, one of the following:

– 9 V wall-mount power supply (100–120 VAC) – 9 V wall-mount power supply (220–240 VAC)

❑ T ype XI or X2 single-shielded or double-shielded GPIB cable (1, 2, or

4 m), which you can purchase from National Instruments

Caution

double-shielded GPIB cable. If you operate this equipment with a non-shielded cable, it may interfere with radio and television reception.

To meet FCC emission limits for this device, you must use a Type X2

Optional Equipment

You can order a 9-pin, 2 m RS-232 shielded cable (GPIB-232CV-A to IBM PC) from National Inst ruments.

GPIB-232CV-A User Manual 1-2 www.ni.com

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Inspection

Before you operate the GPIB-232CV-A, inspect the shipping container and its contents for damage. Keep the packing material for possible inspection and/or reshipment.

If the equipment appears to be damaged, do not attempt to operate it. Contact National Instruments for instructions. If the damage appears to have been caused in shipment, file a claim with the carrier.

GPIB-232CV-A Panels

The following sections describe the panels of the GPIB-232CV-A.

AC Front Panel

The power switch, fuse holder, and power cord receptacle are located on the GPIB-232CV-A front panel, on the AC version only. Figure 1-1 shows the front panel of the AC version.

Chapter 1 Introduction

FUSE

Figure 1-1.

GPIB-232CV-A AC Front Panel

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Chapter 1 Introduction

Top Panel

The six light-emitting diodes (LEDs) are located on the GPIB-232CV-A top panel. Figure 1-2 shows the top panel.

GPIB-232CV-A

IEEE 488 ConverterRS-232

TALK

LISTEN

BUSY

POWER

READY

FULL

Figure 1-2.

GPIB-232CV-A Top Panel

The LEDs show the current status of the GPIB-232CV-A. Table 1-1 describes each LED.

Table 1-1.

LED Descriptions

LED Indication

POWER Indicates that power has been applied to the unit and

the ON/OFF switch is in the ON position.

READY Indicates that the power-on self-test has successfully

passed and the unit is ready to operate.

TALK Indicates that the GPIB-232CV-A is configured as a

GPIB Talker.

LISTEN Indicates that the GPIB-232CV-A is configured as a

GPIB Listener.

GPIB-232CV-A User Manual 1-4 www.ni.com

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Chapter 1 Introduction

Rear Panel

GPIB ADDRESS

Table 1-1.

LED Descriptions (Continued)

LED Indication

BUSY Indicates that the GPIB-232CV-A is currently

accepting serial data. Each serial character received toggles the status of the BUSY LED.

FULL Indicates that one of the GPIB-232CV-A data buffers

is full. This is not an error condition, but is merely a signal that bus performance may be reduced to the speed of the slower port.

The configuration switches are located on the rear panel of the GPIB-232CV-A. The power switch of the DC version is also located on the rear panel.

Figure 1-3 shows the rear panel of the GPIB-232CV-A.

MODE

CONFIG

O N

BAUD RATE DATA FORMAT HANDSHAKE

12345678

Figure 1-3.

12345678

GPIB-232CV-A Rear Panel

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Chapter 1 Introduction

Side Panels

The GPIB connector and the RS-232 connector are mounted on opposite side panels. On the DC version, the DC power jack is on the same end as the serial connector.

Figure 1-4 shows the location of the RS-232 and GPIB connectors and the DC power jack.

DC Power Jack

(DC version only)

GPIB-232CV-A

IEEE 488 ControllerRS-232

POWER

RS-232 Connector

Figure 1-4.

Location of the Connectors and the DC Power Jack

READY

TALK

BUSY

LISTEN

GPIB Connector

FULL

GPIB-232CV-A User Manual 1-6 www.ni.com

Page 17

Chapter 1 Introduction

RS-232 Connector

The RS-232 port on the GPIB-232CV-A is configured as a DTE (Data Terminal Equipment) and uses a standard 9-pin shielded D-Subminiature male connector with screwlock assemblies. The RS-232 connector accepts standard 9-pin D-Subminiature female connectors. Figure 1-5 shows a diagram of the serial connector and the signals supported. For more information on the RS-232 signals refer to Appendix B, Interfacing to a

Serial Device.

No Connection

Figure 1-5.

6789

RTS CTS

No Connection

23451

RXD TXD DTR GND

RS-232 Connector and Signal Designations

Page 18

Chapter 1 Introduction

GPIB Connector

The GPIB connector is a standard 24-pin shielded Champ female connector with metric screwlock hardware. Figure 1-6 shows a diagram of the GPIB connector and the signals supported. A * suffix indicates that the signal is active low.

DIO1* DIO2* DIO3* DIO4*

EOI*

DAV* NRFD* NDAC*

IFC*

SRQ*

ATN*

SHIELD

Figure 1-6.

1 2 3 4 5 6 7 8 9 10 11 12

DIO5*

DIO6*

DIO7*

DIO8*

REN*

GND (Twisted Pair with DAV*)

GND (Twisted Pair with NRFD*)

GND (Twisted Pair with NDAC*)

GND (Twisted Pair with IFC*)

GND (Twisted Pair with SRQ*)

GND (Twisted Pair with ATN*)

SIGNAL GROUND

GPIB Connector and Signal Designations

GPIB-232CV-A User Manual 1-8 www.ni.com

Page 19

Configure and Install Your Hardware

This chapter describes how to configure and install your GPIB-232CV-A.

Configure Your Hardware

Before you configure your GPIB-232CV-A, verify that the voltage marked on the GPIB-232CV-A or on the power supply matches the voltage that is supplied in your area.

Caution

on your GPIB-232CV-A. Doing so could damage the unit. Replacement fuses for the AC version must be the proper type and size. For fuse specifications, refer to Appendix A,

Specifications.

Do not operate your GPIB-232CV-A at any voltage other than the one marked

Your GPIB-232CV-A is configured at the factory, as follows:

•D mode

• GPIB primary address 5

• SRQ feature disabled

• Serial port is configured to: – 9600 baud – 1 stop bit per character – Parity generation/checking disabled – 7 data bits per character – XON/XOFF protocol disabled

If you want to change any of the GPIB-232CV-A characteristics, you must change the configuration switches. For information on choosing the mode of operation, refer to Choosing Between D Mode and C Mode

Configuration in Chapter 3, Operation of the GPIB-232CV-A. Chapter 3

also contains information about choosing whether or not to use other available features.

Page 20

Chapter 2 Configure and Install Your Hardware

If you are already using the GPIB-232CV-A and decid e to change its operating characteristics, you must first shut down your system and then continue with the following steps.

Configure the GPIB-232CV-A Parameters

You can use the DIP switches on the rear panel (see Figure 1-1,

GPIB-232CV-A AC Front Panel, and Figure 1-4, Location of the Connectors and the DC Power Jack) to configure the GPIB-232CV-A.

Figure 2-1 shows the factory default setting for SW1.

MODE

CONFIG

GPIB ADDRESS

O N

12345678

SW1

Figure 2-1.

Factory Default Switch Settings for SW1

In Figure 2-1, switches 1 through 5 are ON, OFF, ON, OFF, and OFF, respectively, indicating a GPIB primary address of 5. Switches 6 and 7 are in the OFF position, indicating that SRQ is disabled and the small serial buffer is used. Switch 8 is in the OFF position, indicating that the unit is configured to operate in D mode.

T ables 2-1, 2-2, and 2-3 show the possible configurations of SW1 and what the configurations indicate. Default settings appear in bold italics.

Table 2-1.

Configuration Parameters for SW1 Switches 1 through 5

Switches

Indication1 2 3 4 5

OFF OFF OFF OFF OFF GPIB Primary Address 0 ON OFF OFF OFF OFF GPIB Primary Address 1 OFF ON OFF OFF OFF GPIB Primary Address 2 ON ON OFF OFF OFF GPIB Primary Address 3 OFF OFF ON OFF OFF GPIB Primary Address 4

GPIB-232CV-A User Manual 2-2 www.ni.com

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Chapter 2 Configure and Install Your Hardware

Table 2-1. Configuration Parameters for SW1 Switches 1 through 5 (Continued)

Switches

Indication1 2 3 4 5

ON OFF ON OFF OFF GPIB Primary Address 5

OFF ON ON OFF OFF GPIB Primary Address 6 ON ON ON OFF OFF GPIB Primary Address 7 OFF OFF OFF ON OFF GPIB Primary Address 8 ON OFF OFF ON OFF GPIB Primary Address 9 OFF ON OFF ON OFF GPIB Primary Address 10 ON ON OFF ON OFF GPIB Primary Address 11 OFF OFF ON ON OFF GPIB Primary Address 12 ON OFF ON ON OFF GPIB Primary Address 13 OFF ON ON ON OFF GPIB Primary Address 14 ON ON ON ON OFF GPIB Primary Address 15 OFF OFF OFF OFF ON GPIB Primary Address 16 ON OFF OFF OFF ON GPIB Primary Address 17 OFF ON OFF OFF ON GPIB Primary Address 18 ON ON OFF OFF ON GPIB Primary Address 19 OFF OFF ON OFF ON GPIB Primary Address 20 ON OFF ON OFF ON GPIB Primary Address 21 OFF ON ON OFF ON GPIB Primary Address 22 ON ON ON OFF ON GPIB Primary Address 23 OFF OFF OFF ON ON GPIB Primary Address 24 ON OFF OFF ON ON GPIB Primary Address 25 OFF ON OFF ON ON GPIB Primary Address 26 ON ON OFF ON ON GPIB Primary Address 27 OFF OFF ON ON ON GPIB Primary Address 28

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Chapter 2 Configure and Install Your Hardware

Table 2-1. Configuration Parameters for SW1 Switches 1 through 5 (Continued)

ON OFF ON ON ON GPIB Primary Address 29 OFF ON ON ON ON GPIB Primary Address 30 ON ON ON ON ON Listen-Only Operation

Table 2-2. Configuration Parameters for SW1 Switches 6 and 7

Switches Indication

6 7 D Mode C Mode

Switches

Indication1 2 3 4 5

(D Mode) or No Addressing Performed (C Mode)

OFF OFF SRQ Disabled and

Timeout Termination

Small Serial Buffer

ON OFF SRQ Enabled and

CR Termination

Small Serial Buffer

OFF ON SRQ Disabled and

LF Termination

Large Serial Buffer

ON ON SRQ Enabled and

No Swapping

Large Serial Buffer

Table 2-3. Configuration Parameters for SW1 Switch 8

Switch 8 Position Indication

OFF GPIB-232CV-A Operates in D Mode

ON GPIB-232CV-A Operates in C Mode

GPIB-232CV-A User Manual 2-4 www.ni.com

Page 23

Configure the Serial Port Parameters

You can use the DIP switch SW2 on the rear panel (see Figure 1-3,

GPIB-232CV-A Rear Panel, and Figure 1-4, Location of the Connectors and the DC Power Jack) to configure the serial port parameters of the

GPIB-232CV-A. Figure 2-2 shows the factory default setting.

O N

Chapter 2 Configure and Install Your Hardware

BAUD RATE DATA FORMAT HANDSHAKE

12345678

SW2

Figure 2-2.

Factory Default Switch Settings for SW2

In Figure 2-2, switches 1 through 3 are ON, OFF, and ON, respectively, indicating that the serial port is operating at 9600 baud. Switches 4 and 5 are both OFF, which indicates that parity is disabled. Switch 6 is OFF, which indicates 1 stop bit per character. Switch 7 is OFF, indicating that the GPIB-232CV-A is using 7 bits/character for its serial data transfers. Switch 8 is OFF, indicating that XON/XOFF software handshaking is disabled.

Tables 2-4 and 2-5 show the possible configurations of SW2 and what the configurations indicate. Default settings appear in bold italics.

Table 2-4.

Configuration Parameters for SW2 Switches 1 through 3

Switches

Indication1 2 3

OFF OFF OFF 300 baud ON OFF OFF 600 baud OFF ON OFF 1200 baud ON ON OFF 2400 baud OFF OFF ON 4800 baud

ON OFF ON 9600 baud

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Chapter 2 Configure and Install Your Hardware

Table 2-4.

OFF ON ON 19200 baud ON ON ON 38400 baud

Switch Position Indication

Configuration Parameters for SW2 Switches 1 through 3 (Continued)

Switches

Indication1 2 3

Table 2-5.

4 OFF Odd parity

5 OFF Parity generation/checking disabled

6 OFF 1 stop bit per character

7 OFF 7 bits per character

Configuration Parameters for SW2 Switches 4 through 8

ON Even parity

ON Parity generation/checking enabled

ON 2 stop bits per character

ON 8 bits per character

8 OFF XON/XOFF protocol disabled

ON XON/XOFF protocol enabled

Install Your Hardware

After configuring the switch settings on your GPIB-232CV-A, complete the following steps to install the GPIB-232CV-A.

Step 1. Shut Down Your System

Before you connect the cables, complete the following steps:

1. Shut down your system.

2. Turn off your computer and unplug the power cord.

GPIB-232CV-A User Manual 2-6 www.ni.com

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Chapter 2 Configure and Install Your Hardware

Step 2. Verify That You Have a Null-Modem Serial Cable

You must use a null-modem serial cable (also known as a file transfer cable or a DTE-to-DTE cable) to connect your computer to the GPIB-232CV-A. The following National Instruments cables are null-modem serial cables.

National Instruments

See Appendix B, Interfacing to a Serial Device, for more information regarding cable pinouts.

Step 3. Connect the Cables

To connect the cables, complete the following steps:

1. Connect the serial cable to the GPIB-232CV -A 9-pin D-Sub connector and securely fasten the holding screws. Connect the other end of the cable to your serial device. Be sure to use only shielded serial cables, and follow all RS-232 cabling restrictions.

2. Connect the GPIB cable to the GPIB-232CV-A 24-pin Champ connector and tighten the thumb screws on the connector . Connect the other end to your GPIB system. Be sure to use only shielded GPIB cables, and follow all IEEE 488 cabling restrictions.

3. If you have an AC version, connect the power cord to the power receptacle on the front panel of the GPIB-232CV-A, then plug the supply into an AC outlet of the correct voltage.

If you have a DC version, connect the DC power plug of the DC power supply to the power jack on the serial end of the GPIB-232CV-A, then plug the supply into an AC outlet of the correct voltage.

Table 2-6.

Part Number

182238-01 9-pin to 9-pin, 1 m 182238-02 9-pin to 9-pin, 2 m 182238-04 9-pin to 9-pin, 4 m 181074-10 9-pin to 25-pin, 1 m

National Instruments Null-Modem Serial Cables

Cable Type

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Chapter 2 Configure and Install Your Hardware

Step 4. Power on Your System and Switch on Your GPIB-232CV-A

1. Plug the power cords for your computer system into a power outlet and power on all devices.

2. If you have an A C v ersion, use the front panel rocker switch to power on your GPIB-232CV-A. If you have a DC version, use the power switch on the rear panel to power on your GPIB-232CV-A.

The POWER LED indicator should come on immediately. The READY LED indicator should come on after the GPIB-232CV-A has passed its power-on self test, indicating the unit is ready for operation. If the READY LED does not come on within seven seconds after the unit is powered on, recheck all connections and switch settings and retry the power-on sequence. If the READY LED still does not come on, contact National Instruments for technical support.

GPIB-232CV-A User Manual 2-8 www.ni.com

Page 27

Operation of the GPIB-232CV-A

This chapter describes how to choose between D mode configuration and C mode configuration and contains information about operating the GPIB-232CV-A in D mode or C mode, data buffering, and handshaking schemes.

The following terms are specific to the sections in this chapter:

• A * suffix after a mnemonic indicates active low.

•A bold mnemonic indicates that it is a signal name, or a top panel

LED indicator.

• <CR> is the symbol for the Carriage Return character (hex 0D).

• <LF> is the symbol for the Linefeed character (hex 0A).

Choosing Between D Mode and C Mode Configuration

The GPIB-232CV-A can be configured either as a GPIB device that is addressed to talk or listen by a GPIB Controller on the bus (D mode), or as a GPIB Controller that addresses a single GPIB device to talk or listen (C mode).

When to Use D Mode

The GPIB-232CV-A should be set to operate in D mode if you want to connect a serial device to a GPIB system that has a GPIB Controller responsible for addressing the GPIB-232CV-A to talk or listen. An example of a system requiring D mode includes a serial device, such as a printer, connected to a GPIB system with an existing GPIB Controller,

Page 28

Chapter 3 Operation of the GPIB-232CV-A

such as an IBM PC AT computer with a National Instruments AT-GPIB IEEE 488.2 board installed, as shown in Figure 3-1.

GPIB Device

Printer

(Serial Device)

When to Use C Mode

The GPIB-232CV-A should be set to operate in C mode when transferring data between a GPIB device that has no Controller capabilities and a serial device. An example of a system requiring C mode includes a GPIB device, such as a digital multimeter, connected to an IBM PC serial port through a GPIB-232CV-A as shown in Figure 3-2.

Serial Cable

GPIB Cables

GPIB-232CV-A

POWER

READY

TALK

LISTEN

BUSY

FULL

FUSE

GPIB-232CV-A

IBM PC AT

(GPIB Controller)

Figure 3-1. Example of D Mode System Setup

POWER

READY

TALK

LISTEN

FUSE

GPIB Cable

BUSY

FULL

GPIB-232CV-A

IBM PC

(Serial Device)

Digital Multimeter

(GPIB Device)

Figure 3-2. Example of C Mode System Setup

GPIB-232CV-A User Manual 3-2 www.ni.com

Page 29

D Mode Overview

In D mode, the GPIB-232CV-A acts as another device on the bus. Figure 3-3 shows the D mode system layout.

GPIB-232CV-A

POWER

BUSY

READY

TALK

LISTEN

FULL

FUSE

GPIB-232CV-A

Serial Device

Chapter 3 Operation of the GPIB-232CV-A

Controller

GPIB

Device

GPIB

Device

GPIB

Device

In D mode, the GPIB-232CV-A can act only as a GPIB Talker or Listener. Do not pass control to the GPIB-232CV-A when using D mode. If you do, the GPIB circuitry in the GPIB-232CV-A accepts control and immediately asserts the ATN* signal, a system error condition that you should avoid.

Because the GPIB-232CV -A is not System Controller in D mode, it expects to receive GPIB commands from the Controller-In-Charge (CIC). If the GPIB-232CV-A receives the universal De vice Clear (DCL) command or is addressed to listen and receives the Selected Device Clear (SDC) command, it clears its internal data buf fers and resets to its po wer -up state. Neither Trigger (GET) nor Go To Local (GTL) have any effect on the GPIB-232CV-A.

Data Transfers in D Mode

When you are ready to send data to the GPIB-232CV-A in D mode, address the GPIB-232CV-A to listen, if not already in listen-only mode. All GPIB data received by the GPIB-232CV-A is buffered and passed along to the serial device. When you are expecting to receive data from the serial device, address the GPIB-232CV-A to talk, and all data received over the serial port is passed along to the GPIB port.

Figure 3-3.

D Mode System Layout

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Chapter 3 Operation of the GPIB-232CV-A

Choosing a Serial Port Buffer Size

All data that is sent to the GPIB-232CV-A is buffered and then passed along to the destination port. Thus, any serial data received is buffered and then passed along to the GPIB port whenever the GPIB-232CV-A is addressed to talk. The GPIB-232CV-A has 256 KB of RAM for buffering. In D mode, this memory can be allocated between the serial and GPIB buffers in two possible configurations.

The size of the serial input buffer can be set to either 256 bytes (SW1 switch 7 set to OFF), or 32 KB (SW1 switch 7 set to ON) with the remainder of the 256 KB of RAM allocated to the GPIB buffer.

• S et the serial input buffer size to 256 bytes if only small amounts of data, such as status information from a plotter, are expected to be sent from the serial device to the GPIB-232CV-A.

• S et the serial input b uffer size to 32 KB if you expect the serial device to send large amounts of data to the GPIB-232CV-A, such as an RS-232 instrument sending thousands of bytes of measurements.

In either case, the remainder of RAM space is used as the GPIB input buffer. Thus, if a large amount of GPIB data is expected to be sent to the GPIB-232CV-A, it would be advantageous to use the small 256 byte serial port buffer size if possible. Then the majority of RAM is used as the GPIB buffer. The larger serial buffer size is a means of capturing a larger percentage of the total RAM space for serial input use.

Regardless of the buf fer size you choose, serial data is not lost because the GPIB-232CV-A implements a hardware handshake scheme, and if selected, the XON/XOFF software handshake scheme. The variable b uffer size is a means of optimizing the GPIB-232CV-A for your application.

Using the SRQ Feature

The GPIB bus performance might slow down if the Controller is constantly waiting for the GPIB-232CV-A to send or receive data. With SRQ enabled, the bus can be used by other devices until the GPIB-232CV-A requests service (asserts SRQ*). When the GPIB-232CV-A asserts SRQ*, the Controller serial polls the GPIB-232CV-A to determine what type of service it needs. After it is serial polled, the GPIB-232CV-A unasserts SRQ*. You can enable the SRQ feature by setting switch 6 of SW1 to the ON position.

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Chapter 3 Operation of the GPIB-232CV-A

Conditions That Cause SRQ to be Asserted

If SRQ is enabled, the GPIB-232CV-A asserts the SRQ* signal on two conditions:

• When the GPIB-232CV-A receives serial data that it needs to pass on to the GPIB port

• When the GPIB input buffer becomes empty

When the GPIB-232CV-A serial input buffer is empty and the GPIB-232CV -A recei ves a serial character to be sent along to the GPIB, the SRQ* signal is asserted. This alerts the GPIB Controller that the GPIB-232CV-A has data to send to a GPIB Listener. The Controller can then address the GPIB-232CV-A to talk so that the data can be read out of the GPIB-232CV-A serial buffer. When the serial buffer is empty, the Controller can unaddress the GPIB-232CV-A to talk and address other devices to transfer data on the bus.

SRQ* is also asserted when the GPIB input buffer becomes empty. When the GPIB-232CV-A has emptied out the buffer, it requests service, indicating it is ready for more data. The Controller can then readdress the GPIB-232CV -A to listen and continue sending data until all the data is sent.

Maximizing Performance with SRQ

If large amounts of data (greater than the GPIB buffer size) are sent over the GPIB to the GPIB-232CV-A and the serial device is a very slow data acceptor, the GPIB-232CV-A internal GPIB data buffer might become full. If this occurs, the FULL indicator on the front panel illuminates and the GPIB transfer rate slows to approximately the same rate as the serial device that is accepting the data. Because the maximum data transfer rate on the GPIB is only as fast as the slowest Listener, the GPIB system performance may become unacceptable if other GPIB devices are required to transfer data on the bus.

To get maximum GPIB performance when large amounts of data are sent to the GPIB-232CV -A, enable the SRQ feature and send only data amounts up to but not exceeding the GPIB input b uffer size. The Controller can then unaddress the GPIB-232CV-A to listen so that other devices can use the bus. When the GPIB-232CV-A is ready to receive more data, it asserts the SRQ* signal.

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Chapter 3 Operation of the GPIB-232CV-A

GPIB-232CV-A Serial Poll Responses

If the GPIB-232CV-A is serial polled, its response byte depends on the status of the internal data buffers, as follows:

• If the serial input buffer is empty, bit 1 of the status byte is set to 1.

• If the serial input buffer is not empty, bit 1 is set to 0.

• If the GPIB input buffer is empty, bit 0 of the status byte is set to 1.

• If the GPIB input buffer is not empty, bit 0 is set to 0. In all cases, bit 6 is set to 1 if the GPIB-232CV-A is requesting service;

otherwise it is set to 0.

GPIB-232CV-A Operation in Listen-Only Mode

In listen-only mode, no addressing is required to make the GPIB-232CV-A a GPIB Listener and it cannot be unaddressed to listen. All data transferred on the GPIB is accepted by the GPIB-232CV-A and output to the serial port even if the data was intended for another device. This configuration can be used to monitor all GPIB data bus activity. Notice that when the GPIB-232CV-A is configured as a listen-only device, it cannot be serial polled.

The GPIB primary address for the GPIB-232CV -A is specified b y switches 1 through 5 of the DIP switch SW1. If GPIB address switches 1 through 5 are all set to ON, the GPIB-232CV-A is configured as a listen-only device. Figure 3-4 shows the switch settings for listen-only mode.

MODE

CONFIG

GPIB ADDRESS

O N

12345678

SW1

Figure 3-4.

GPIB-232CV-A User Manual 3-6 www.ni.com

Switch Settings for Listen-Only Mode

Page 33

C Mode Overview

In C mode, the GPIB-232CV-A and a serial device together act as the GPIB System Controller. Figure 3-5 shows the C mode system layout.

Serial

Device

GPIB Controller

GPIB-232CV-A

Chapter 3 Operation of the GPIB-232CV-A

POWER

READY

TALK

LISTEN

BUSY

FULL

FUSE

GPIB

Device

When you turn the power on with the GPIB-232CV-A in C mode, the GPIB-232CV-A asserts IFC* for 500 µs and addresses the instruments to listen. On a GPIB system, asserting IFC* for at least 100 µs initializes the GPIB and causes the System Controller to become Controller-In-Charge (CIC).

After the GPIB-232CV-A beco mes CIC, it sends out the GPIB listen address indicated by SW1 switches 1 through 5. If switches 1 through 5 are all ON, no addressing is performed. This configuration is useful if you are talking to a listen-only device that does not require addressing. The GPIB-232CV-A always asserts REN* when addressing other devices.

Data Transfers in C Mode

All incoming serial data to the GPIB-232CV-A is stored in an internal data buffer until it is accepted by the GPIB device. All GPIB data sent to the GPIB-232CV-A is passed immediately to the serial port without being buffered. You can send data to your serial port as if you had a serial device connected to it. The data is converted and sent to the GPIB instrument. When the instrument has data to send back, the GPIB-232CV-A addresses the instrument to talk and passes all received data to the RS-232 port.

Figure 3-5.

C Mode System Layout

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Chapter 3 Operation of the GPIB-232CV-A

Modes of Operation Within C Mode

Four different modes of operation are available within C mode to define when the GPIB device is addressed to talk or listen. These modes are as follows:

• Timeout termination

• <CR> termination

• <LF> termination

•No-swap In every mode, the device is addressed to listen after the GPIB-232CV-A

becomes CIC, and all data received via the serial port is b uffered and passed along to the device. The four modes of operation define the point at which the GPIB device is unaddressed to listen and addressed to talk so that data can be sent from the device to the GPIB-232CV-A. You can select these modes using SW1 switches 6 and 7.

Timeout Termination Mode

Timeout termination mode should be used for applications in which bidirectional communication is required and neither a <CR> nor <LF> character is used to signal the end of a command string to the GPIB device. To select timeout termination mode, set SW1 switches 6 and 7 to OFF. Figure 3-6 shows the cycle of events in timeout termination mode.

Serial

Device

Receive Serial

Data

Serial

Device

GPIB-232CV-A

POWER

READY

TALK

LISTEN

BUSY

DATA DATA

Figure 3-6.

GPIB-232CV-A

Timeout Termination Mode Cycle

FULL

FUSE

POWER

READY

TALK

LISTEN

BUSY

FULL

FUSE

GPIB Device

Addressed

to Talk

Serial Buffer Empty and No Serial Data

Received for 300 msec

GPIB Device

Addressed

to Listen

GPIB-232CV-A User Manual 3-8 www.ni.com

Page 35

Chapter 3 Operation of the GPIB-232CV-A

In timeout termination mode, the GPIB-232CV-A addresses the GPIB device to talk, and any characters read from the GPIB port are passed along immediately to the serial port. When a serial character is received by the GPIB-232CV-A, it immediately readdresses the GPIB device to listen and passes the character to it. It remains in this mode until its serial input buffer becomes empty and no serial characters are received for 300 ms. After this period of inactivity, the GPIB-232CV-A assumes that since no more serial data is being sent, the device might have data that it needs to send back to the GPIB-232CV-A. It then readdresses the device to talk and passes any characters read from the GPIB port along to the serial port.

<CR> or <LF> Termination Mode

If a command string to the GPIB instrument can be terminated with either a <CR> (carriage return) or <LF> (linefeed) character, you can use either termination with <CR> or <LF> to readdress the GPIB device to send data. To select <CR> mode, set SW1 switch 6 to ON and 7 to OFF. To select <LF> mode, set SW1 switch 6 to OFF and 7 to ON.

In these modes, when the GPIB-232CV-A receives the terminating character from the serial port, it addresses the device to talk so that any GPIB data can be input by the GPIB-232CV-A. Then any serial character received by the GPIB-232CV-A signals the GPIB-232CV-A to readdress the GPIB device as a Listener . F or e xample, you might want to connect an HP7475 GPIB plotter to an IBM PC serial port using the GPIB-232CV-A. To then draw a line, get plotter status, and draw a circle you could use the following BASIC commands:

10 OPEN "COM1:9600,n,8,1" AS #1 'Assumes

'GPIB-232CV-A is 'at 9600 baud, 'no parity, 8 'data bits, 1 'stop bit.

20 PRINT #1,"pa1000,1000 os" 'Plot absolute to

'1000,1000 then 'output status.

30 LINE INPUT #1,RESPONSE$ 'Get status

'response from 'plotter.

40 PRINT #1 "ci100"; 'Draw circle

'with radius of '100 units.

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Chapter 3 Operation of the GPIB-232CV-A

Line 20 of the program outputs plotter commands to the serial port to both draw a line and obtain status. Because neither a <CR> nor <LF> is sent between these commands, the GPIB-232CV-A keeps the GPIB plotter addressed to listen and sends all serial data received to the plotter . Because the

PRINT statement is not ended with a semicolon after the double

quotation mark, BASIC automatically sends a <CR> after the last character in the ASCII string is sent. If the GPIB-232CV-A is set up for <CR> termination, the GPIB-232CV-A then readdresses the plotter to talk so that its status can be output.

Line 30 inputs the status response from the plotter into the string variable

RESPONSE$.

Line 40 outputs the plotter command to the GPIB-232CV-A to draw a circle. As soon as the GPIB-232CV-A receives the first character in this string, it readdresses the plotter to listen and then sends these characters to it. Notice that for this double quotation mark. This means a <CR> is not sent. Because no information is requested from the plotter, there is no need to send a <CR> at the end of the string to address the plotter to talk.

No-Swap Mode

In no-swap mode, the GPIB-232CV-A never readdresses a GPIB device after it has initially been addressed as a Listener. To select no-swap mode, set SW1 switches 6 and 7 to ON.

PRINT statement a semicolon is included after the last

This mode is useful if your device is intended only to receive data. In the example given in the <CR> or <LF> Termination Mode section of this chapter, you could use the no-swap mode to talk to the plotter if you never needed to obtain status information from it. By adding a semicolon after the double quotation mark at the end of line 20 as shown below, you suppress the <CR>. Since you cannot readdress in no-swap mode, the <CR> is not needed to obtain status as it was in the previous example.

10 OPEN "COM1:9600,n,8,1" AS #1 'Assumes

'GPIB-232CV-A is 'at 9600 baud, 'no parity, 8 'data bits, 1 'stop bit.

20 PRINT #1,"pa1000,1000"; 'Plot absolute to

'1000,1000.

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Chapter 3 Operation of the GPIB-232CV-A

30 PRINT #1 "ci100"; 'Draw circle

'with radius of '100 units.

Data Buffering and Handshaking Schemes

Two protection mechanisms are used to ensure that the GPIB-232CV-A does not lose incoming serial data: data buffering and handshaking.

The GPIB-232CV -A has an internal RAM buf fer that stores incoming serial data until it can output the data to the GPIB port. The size of this RAM buffer determines how much serial data the GPIB-232CV-A can accept before the buffer is completely full.

When its RAM buffer is nearly full, the GPIB-232CV-A can handshake with the serial host to stop data transmission. When the buffer is almost empty , the GPIB-232CV-A can again handshake with the serial host to start data transmission. The GPIB-232CV-A is capable of using both the XON/XOFF software handshaking and the hardware handshaking protocols.

Hardware Handshaking

The hardware handshake function is always active during RS-232 transfers and uses the Request to Send (RTS) and Clear to Send (CTS) signal lines. When the GPIB-232CV-A is ready to accept serial data, it asserts the RTS line. This signal remains asserted until the data buffer of the GPIB-232CV-A is almost full. At this point, the GPIB-232CV-A unasserts the RTS line, signaling to the serial host that the GPIB-232CV-A is no longer ready to accept data. The serial host should monitor the RTS line and suspend data transmission whenever the RTS line becomes unasserted. The GPIB-232CV-A asserts RTS when it is again ready to receive serial data.

The GPIB-232CV-A is also able to suspend transmission when the serial device is no longer ready to accept data. The GPIB-232CV-A is configured to immediately stop transmission of serial data when CTS becomes unasserted. The GPIB-232CV-A resumes transmission as soon as CTS is reasserted.

Because most serial devices use the same form of hardware handshaking as the GPIB-232CV -A, you can achiev e bidirectional flow control by using a serial cable that connects the RTS signal of the GPIB-232CV-A to the CTS signal of the serial device. In addition, the RTS signal of the serial device should be connected to the CTS signal of the GPIB-232CV-A. This

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Chapter 3 Operation of the GPIB-232CV-A

setup allows each device to monitor the RTS signal of the other device and to suspend transmission when necessary to prevent data loss. Refer to Appendix B, Interfacing to a Serial Device, for more information on wiring schemes.

XON/XOFF Software Handshaking

If your serial device does not implement or recognize the hardware handshake scheme, your cable does not support the necessary handshake lines, or your application software requires XON/XOFF handshaking, you might need to enable the XON/XOFF handshaking protocol by setting switch 8 of SW2 to ON. This handshaking protocol performs the same function as the hardware handshake but does so by sending special control codes over the data lines instead of changing logic levels on dedicated control lines.

When you enable the XON/XOFF protocol, the GPIB-232CV-A sends the XOFF character (decimal 19 or <Ctrl-S>) before the internal buffer overflows. When the GPIB-232CV-A is able to start receiving characters again, it sends the XON character (decimal 17 or <Ctrl-Q>). Similarly, if the GPIB-232CV-A is transmitting data and receives the XOFF character, it suspends transmission of any further data until it receives the XON character.

If you are transmitting binary data, do not configure the GPIB-232CV-A to use XON/XOFF software handshaking. Because the binary data could contain any binary sequence, including decimal 19 (<Ctrl-S>) or decimal 17 (<Ctrl-Q>), the GPIB-232CV - A would not be able to distinguish between data values or handshake control codes. If handshaking were enabled, the GPIB-232CV-A would handshake erratically.

GPIB-232CV-A User Manual 3-12 www.ni.com

Page 39

Specifications

This appendix lists the electrical, environmental, and physical characteristics of the GPIB-232CV-A .

Electrical Characteristics

AC Version

Power supply unit

100–120 VAC ±10% ...................... 50–60 Hz

220–240 VAC ±10% ...................... 50–60 Hz

Current requirement

100–120 VAC.................................55 mA

220–240 VAC.................................45 mA

Fuse rating and type

100–120 VAC.................................300 mA, UL/CSA approved

220–240 VAC.................................500 mA, IEC approved

DC Version

Power supply unit (50–60 Hz input, 9 VDC at 1 A output)

Wall-mount type ............................. 100–120 VAC ± 10%

Desktop type ................................... 220–240 VAC ± 10%

DC input.................................................+5 to +13, regulated

Current ...................................................700 mA minimum

Environmental Characteristics

AC Version

Operating temperature............................10 to 40 °C

Storage temperature ...............................0 to 70 °C

Page 40

Appendix A Specifications

Relative humidity ...................................10% to 95%, noncondensing

EMI.........................................................FCC Class A Verified

DC Version

Operating temperature............................10 to 40 °C

Storage temperature................................0 to 70 °C

Relative humidity ...................................10% to 95%, noncondensing

EMI.........................................................FCC Class B Certified

Physical Characteristics

AC Version

Case size .................................................118.1 by 76.2 by 44.2 mm

Case material ..........................................All metal enclosure

Weight ....................................................340 g (12 oz)

(4.65 by 3.0 by 1.74 in.)

DC Version

Case size .................................................118.1 by 76.2 by 28.2 mm

(4.65 by 3.0 by 1.11 in.)

Case material ..........................................All metal enclosure

Weight ....................................................198 g (7 oz)

GPIB-232CV-A User Manual A-2 www.ni.com

Page 41

Interfacing to a Serial Device

This appendix describes the RS-232 serial port on the GPIB-232CV -A and explains how to interface a DCE or DTE serial device to the RS-232 serial port.

The GPIB-232CV-A transfers serial data using the electrical signals, mechanical connections, data format, and control protocols defined in the RS-232C standard. The RS-232 port on the GPIB-232CV-A is an asynchronous serial communication link to a serial peripheral device.

RS-232C Standard

The RS-232C standard (international standard CCITT V.24) was formulated in 1969 largely from the efforts of the Electronic Industries Association (EIA) and Bell Laboratories. The standard describes the electrical specifications and arrangement of control and data signals on both sides of a serial communications interface. Its original intent was to interface terminals to modems. Many manufacturers of computers and instruments have adopted the standard for their serial communications needs. For more information on the RS-232C standard, contact

Global Engineering Documents 7730 Carondelet Avenue, Suite 4007 St. Louis, MO 63105 (800) 854-7179

Page 42

Appendix B Interfacing to a Serial Device

RS-232 Port Overview

The RS-232 serial port on the GPIB-232CV-A uses a male 9-pin D-Subminiature connector with a DTE interface configuration. Table B-1 shows the signal lines supported on the GPIB-232CV-A.

Number

2 RXD

3 TXD

4 DTR

5 GND

7 RTS

8 CTS

Table B-1.

Signal Description

(Receive Data)

(Transmit Data)

(Data Terminal Ready)

(Ground)

(Request to Send)

(Clear to Send)

RS-232 Serial Port Signal Configuration

RS-232

Code

BB This signal carries serial data from the serial

device to the GPIB-232CV-A.

BA This signal carries serial data from the

GPIB-232CV-A to the serial device.

CD This signal is asserted by the GPIB-232CV-A to

signal that it has been powered on and is ready to operate.

AB This signal establishes a reference point for all

interface voltages.

CA This signal is driven by the GPIB-232CV-A.

When asserted, it indicates that the GPIB-232CV-A is ready to accept serial data. When unasserted, it indicates that the GPIB-232CV-A is no longer ready to accept serial data because the buffer is full.

CB This signal is sensed by the GPIB-232CV-A.

When asserted, it indicates that the serial device is ready to accept serial data. When unasserted, it indicates that data transmission should be disabled.

Function

Interfacing Serial Devices to the RS-232 Serial Port

To interface other serial devices to the RS-232 serial port on the GPIB-232CV-A, first refer to the manual that came with your serial device to determine if the device is configured as a DTE or DCE. Also, determine from the manual how the control lines are used and whether they must be driven for the serial port to operate.

GPIB-232CV-A User Manual B-2 www.ni.com

Page 43

Appendix B Interfacing to a Serial Device

Figure B-1 shows the location of the RS-232 connector.

DC Power Jack

(DC version only)

GPIB-232CV-A

IEEE 488 ControllerRS-232

TALK

READY

POWER

RS-232 Connector

Figure B-1. Location of the RS-232 Connector

Interfacing the GPIB-232CV-A to a DCE with Handshaking

A correctly configured DTE-to-DCE interface is wired straight across: GPIB-232CV-A TXD to DCE TXD, GPIB-232CV-A RXD to DCE RXD, and so on as shown in Table B-2.

Table B-2. Cable Wiring Scheme for GPIB-232CV-A DTE to Serial Device DCE

Standard

GPIB-232CV-A Signal to

DCE Serial Device Signal

RXD to RXD TXD to TXD

DTE to DCE 9-pin 9-pin

2 to 2 2 to 3 3 to 3 3 to 2

LISTEN

GPIB Connector

BUSY

FULL

Standard

DTE to DCE

9-pin 25-pin

DTR to DTR 4 to 4 4 to 20 GND to GND

5 to 5 5 to 7

RTS to RTS 7 to 7 7 to 4 CTS to CTS 8 to 8 8 to 5

The connections must be implemented.

Page 44

Appendix B Interfacing to a Serial Device

Figure B-2 shows a properly configured 9-pin DTE to 9-pin DCE cable including the hardware handshake lines RTS, CTS, and DTR. With this configuration, the GPIB-232CV-A can function properly (handshake) on buffer full conditions. Figure B-3 shows an equiv alent 9-pin DTE to 25-pin DCE cable configuration.

6 7 8 9

GPIB-232CV-A

9-pin DTE

9 8 7 6

Serial Device

9-pin DCE

Figure B-2. Cable Configuration for 9-pin DTE to 9-pin DCE with Handshaking

6 7 8 9

GPIB-232CV-A

9-pin DTE

14 15 16 17 18 19 20

9 10 11 12 13

22 23 24 25

Serial Device

25-pin DCE

Figure B-3. Cable Configuration for 9-pin DTE to 25-pin DCE with Handshaking

Interfacing the GPIB-232CV-A to a DCE without Handshaking

If your serial device does not require or use the hardware handshaking protocol used by the GPIB-232CV-A, you have two options:

• Use a minimum configuration cable which does not support hardware handshaking and use XON/XOFF software handshaking (if necessary). To create a minimum configuration cable, connect the signals shown in bold italics in Table B-2.

GPIB-232CV-A User Manual B-4 www.ni.com

Page 45

Appendix B Interfacing to a Serial Device

• Wire a custom cable that properly interfaces the GPIB-232CV-A hardware handshaking protocol to the handshaking protocol of your serial device.

Minimum Configuration Cable

The minimum configuration cable assumes that the DCE does not require external hardware handshaking. The minimum configuration for a DTE 9-pin to DCE 9-pin cable is shown in Figure B-4. Figure B-5 shows an equivalent 9-pin to 25-pin cable.

6 7 8 9

GPIB-232CV-A

9-pin DTE

Figure B-4.

6 7 8 9

GPIB-232CV-A

9-pin DTE

9 8 7 6

Serial Device

9-pin DCE

Minimum Configuration for 9-pin DTE to 9-pin DCE

10 11 12 13

4 5 6

8 9

14 15 16 17 18 19 20 21 22 23 24 25

Serial Device

25-pin DCE

Figure B-5.

Minimum Configuration for 9-pin DTE to 25-pin DCE

Page 46

Appendix B Interfacing to a Serial Device

Custom Cables

If your application requires a custom cable, you can construct one if you have a thorough knowledge of the handshaking protocols in volv ed. Revie w the RS-232 characteristics of your serial device and build the cable to properly connect the handshake lines of the two devices. Because the DTE-to-DCE connection is a straight across connection, it often involves only connecting RTS to RTS, CTS to CTS, DTR to DTR, and so on. If the documentation for your serial device does not provide a thorough explanation of its handshaking protocol, the ANSI/EIA-232-C standard is a good reference, provided your device conforms to the RS-232 protocol.

Caution

Although handshaking might not be required, it is best to use some form of

handshaking to prevent loss of data.

Interfacing the GPIB-232CV-A to a DTE with Handshaking

For serial devices set up as DTEs, you must wire a DTE-to-DTE interface cable, commonly known as a null modem cable. The cable allows the GPIB-232CV-A to act as though it is communicating with a DCE, but it swaps the appropriate pins to achieve a DTE pinout. This wiring configuration is shown in Table B-3.

Table B-3.

GPIB-232CV-A Signal to

DTE Serial Device Signal

RXD to TXD TXD to RXD

DTR to DSR 4 to 6 4 to 6 GND to GND RTS to CTS 7 to 8 7 to 5 CTS to RTS 8 to 7 8 to 4

The connections must be implemented.

Cable Wiring Scheme for GPIB-232CV-A DTE to Serial Device DTE

Standard DTE to DTE 9-pin 9-pin

2 to 3 2 to 2 3 to 2 3 to 3

5 to 5 5 to 7

Standard

DTE to DTE

9-pin 25-pin

Figure B-6 shows a typical 9-pin to 9-pin null modem cable with the RTS, CTS, and DTR handshake lines implemented. Figure B-7 shows an equivalent 9-pin DTE to 25-pin DTE cable configuration.

GPIB-232CV-A User Manual B-6 www.ni.com

Page 47

Appendix B Interfacing to a Serial Device

The cable configuration in Figure B-6 allows you to connect to the 9-pin serial port of a personal computer. The cable in Figure B-7 shows how to connect to the 25-pin serial port of a personal computer.

6 7 8 9

GPIB-232CV-A

9-pin DTE

9 8 7 6

Serial Device

9-pin DTE

Figure B-6. Cable Configuration for 9-pin DTE to 9-pin DTE with Handshaking

10 11 12 13

8 9

14 15 16 17 18 19 20 21 22 23 24 25

Serial Device

25-pin DTE

6 7 8 9

GPIB-232CV-A

9-pin DTE

Figure B-7. Cable Configuration for 9-pin DTE to 25-pin DTE with Handshaking

Interfacing the GPIB-232CV-A to a DTE without Handshaking

If your serial device does not require or use the same hardware handshaking protocol used by the GPIB-232CV-A, you have two options:

• Use a minimum configuration null modem cable which does not support the hardware handshake lines and use XON/XOFF software handshaking (if necessary). To create a minimum configuration cable, connect the signals shown in bold italics in Table B-3.

Page 48

Appendix B Interfacing to a Serial Device

• Wire a custom cable that properly interfaces the GPIB-232CV-A hardware handshaking protocol to the handshaking protocol of your serial device.

Minimum Configuration Cable

The minimum cable configuration assumes that the serial device does not require external hardware handshaking. The minimum configuration for a 9-pin to 9-pin null modem cable is shown in Figure B-8. Figure B-9 shows an equivalent 9-pin to 25-pin cable.

6 7 8 9

GPIB-232CV-A

9-pin DTE

Figure B-8.

6 7 8 9

GPIB-232CV-A

9-pin DTE

9 8 7 6

Serial Device

9-pin DTE

Minimum Configuration for 9-pin DTE to 9-pin DTE

9 10 11 12 13

Serial Device

14 15 16 17 18 19 20 21 22 23 24 25

25-pin DTE

Figure B-9.

GPIB-232CV-A User Manual B-8 www.ni.com

Minimum Configuration for 9-pin DTE to 25-pin DTE

Page 49

Appendix B Interfacing to a Serial Device

Custom Cables

If your application requires a custom cable, you can construct one if you have a thorough knowledge of the handshaking protocols inv olved. Revie w the RS-232 characteristics of your serial device and build the cable to properly connect the handshake lines of the two devices. If the documentation for your serial device does not provide a thorough explanation of its handshaking protocol, the ANSI/EIA-232-C standard is a good reference, provided your device conforms to the RS-232 protocol.

Caution

Although handshaking might not be required, it is best to use some form of

handshaking to prevent loss of data.

Page 50

Application Examples

This appendix contains two GPIB-232CV-A application examples. The first example shows how to use the GPIB-232CV-A as a high-speed print spooler, and the second example shows how to connect a HP7475 GPIB plotter to an IBM PC running AUTOCAD.

Using the GPIB-232CV-A as a High-Speed Print Spooler

Because mechanical printers and plotters are slow relati ve to the processing speed of a computer, computers must output data at a slo w rate. This forces you to wait for the data to be output or tolerate decreased performance if the data transfer occurs in the background. One common solution to this problem is to use a print spooler to relieve the computer of this task.

With a GPIB-232CV-A, you can transfer data at GPIB rates instead of RS-232 rates. The GPIB-232CV-A uses a DMA Controller to input data from the GPIB port to the RAM buffer and can input GPIB data at rates up to 625 kbytes/s. Therefore, the transfer rate is limited only by the rate at which the GPIB Talker can write data.

This example shows you how to connect and use your GPIB-232CV-A as a high-speed print spooler which returns control to you quickly, so that you do not have to wait for the PC to finish printing or plotting a file.

The following example is based on the assumption that a National Instruments GPIB interface board (such as the AT-GPIB) is installed in your computer and that you are familiar with the software configuration utility

ibconf. Use the following procedure to set up the system the first

time:

1. Use

2. Configure the GPIB-232CV-A to operate in D mode with the small

ibconf to configure the system so that a device named either

printer or plotter is connected to the GPIB interface board. Be sure to enable DMA transfers and to use high-speed timing.

(256 bytes) serial port buffer and SRQ disabled. The serial buf fer is set to the smallest size to allow the GPIB port, which is the data source, to use the majority of RAM. Set the GPIB address to the same address

Page 51

Appendix C Application Examples

3. Connect the GPIB cable from the PC to the GPIB-232CV-A, and

assigned to the device plotter or printer in ibconf. Configure the serial port parameters to match those of the printer or plotter.

connect the serial cable from the GPIB-232CV-A to the printer or plotter. The system should resemble the diagram in Figure C-1.

Serial Cable

GPIB-232CV-A

GPIB-232CV-APrinter

POWER

TALK

LISTEN

READY

FUSE

GPIB Cable

BUSY

FULL

Figure C-1. Example of Print Spooler Setup

4. Provide a means to transfer data to the printer or plotter easily via the GPIB port on your PC. You can simply redirect the serial output to the GPIB device as explained in the NI-488.2 Software Reference Manual for MS-DOS, but the overhead associated with the DOS calls makes this method inherently slow. The fastest way to transfer data to the GPIB port is to write a small program that executes a GPIB file write. The following program is an example of how to do a GPIB file write in the C programming language. You can use other languages in the same way.

/* FASTPRINT - dumps specified data file out GPIB to device named printer */

#include "decl.h" #include <stdio.h>

main (argc, argv) char **argv; {

char fname [16],*filename; int f;

/* prompt for file name if not provided */

if (argc <=1) {

printf ("Enter filename: "); gets (fname);

GPIB-232CV-A User Manual C-2 www.ni.com

Page 52

Appendix C Application Examples

filename = fname; } else

filename = argv[1]

/* find device printer */

if ((f = ibfind ("printer"))<0) {

fprintf(stderr, "Can't find printer\n");

exit(1); }

/* write file */

if (ibwrtf(f, filename) & ERR) {

fprintf(stderr, "Can't open %s\n", argv[1]);

exit(1); }

}

After the program is compiled and linked, you can run it just like the DOS print routine. Then, as long as you are not sending an amount of data greater than the buffer size of the GPIB-232CV-A, the data transfer should complete in a few seconds.

Connecting a HP7475 GPIB Plotter to a PC Serial Port

Many software packages provide printing and plotting utilities which use your computer’s serial port. If GPIB support is not specifically provided in the package, you cannot communicate with a GPIB device. By using the GPIB-232CV-A, you can avoid this situation because the GPIB-232CV-A allows communication between the serial port and GPIB devices.

For example, an IBM PC running AUTOCAD sends data to the plotter by transferring data through the computer's serial port. It cannot send data to a GPIB plotter such as the HP7475 GPIB plotter. Because AUTOCAD supports the HP7475 serial plotter, you can use the GPIB-232CV-A to convert the serial data from A UT OCAD into GPIB data for the plotter. The GPIB-232CV-A automatically takes care of the GPIB addressing and transparently converts the data from one format to the other. To use the GPIB-232CV-A in this way, follow these steps:

1. Start AUTOCAD and select Configure AUTOCAD from the Main Menu. Select the HP7475 plotter and configure the rest of the operating parameters that you need.

2. Configure your GPIB-232CV-A. Set it to operate in C mode with timeout termination. Set the GPIB address of the plotter using the

Page 53

Appendix C Application Examples

3. Power on the plotter, then power on the GPIB-232CV-A. When the GPIB-232CV-A is powered on, it addresses the GPIB plotter.

Any data sent to the serial port by AUTOCAD is received by the GPIB-232CV-A and stored in its internal buffer. The GPIB-232CV-A transfers the data to the plotter over the GPIB connection as fast as the plotter can receive it. Because the GPIB-232CV-A provides a data buffer that spools the data as it is sent, the PC will be able to send data at serial rates instead of plotter rates. Therefore, your data is output to the GPIB plotter by AUTOCAD in less time than it would have taken to use the HP7475 serial plotter.

GPIB-232CV-A configuration switches. Set the serial port parameters to XON/XOFF disabled, 9600 baud, 7 data bits, 1 stop bit, and even parity.

GPIB-232CV-A User Manual C-4 www.ni.com

Page 54

Technical Support Resources

This appendix describes the comprehensive resources available to you in the Technical Support section of the National Instruments Web site and provides technical support telephone numbers for you to use if you have trouble connecting to our We b site or if you do not have internet access.

NI Web Support

To provide you with immediate answers and solutions 24 hours a day, 365 days a year, National Instruments maintains extensi ve online technical support resources. They are available to you at no cost, are updated daily, and can be found in the Technical Support section of our Web site at

www.ni.com/support

Online Problem-Solving and Diagnostic Resources

• KnowledgeBase—A searchable database containing thousands of frequently asked questions (F A Qs) and their corresponding answers or solutions, including special sections devoted to our newest products. The database is updated daily in response to new customer experiences and feedback.

• Troubleshooting Wizards—Step-by-step guides lead you through common problems and answer questions about our entire product line. Wizards include screen shots that illustrate the steps being described and provide detailed information ranging from simple getting started instructions to advanced topics.

• Product Manu als—A comprehensive, searchable library of the latest editions of National Instruments hardware and software product manuals.

• Hardware Reference Database—A searchable database containing brief hardware descriptions, mechanical drawings, and helpful images of jumper settings and connector pinouts.

• Application Notes—A library with more than 100 short papers addressing specific topics such as creating and calling DLLs, developing your own instrument driver software, and porting applications between platforms and operating systems.

Page 55

Appendix D Technical Support Resources

Software-Related Resources

• Instrument Driver Network—A library with hundreds of instrument

drivers for control of standalone instruments via GPIB, VXI, or serial interfaces. You also can submit a request for a particular instrument driver if it does not already appear in the library.

• Example Programs Database—A database with numerous,

non-shipping example programs for National Instruments programming environments. You can use them to complement the example programs that are already included with National Instruments products.

• Software Library—A library with updates and patches to application

software, links to the latest versions of driver software for National Instruments hardware products, and utility routines.

Worldwide Support

National Instruments has offices located around the globe. Many branch offices maintain a Web site to provide information on local services. You can access these Web sites from

www.ni.com/worldwide

If you have trouble connecting to our Web site, please contact your local National Instruments office or the source from which you purchased your National Instruments product(s) to obtain support.

For telephone support in the United States, dial 512 795 8248. For telephone support outside the United States, contact your local branch office:

Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20, Brazil 011 284 5011, Canada (Calgary) 4 03 274 9391, Canada (Ontario) 905 785 0085, Canada (Québec) 514 694 8521, China 0755 3904939, Denmark 45 76 26 00, Finland 09 725 725 11, France 01 48 14 24 24, Germany 089 741 31 30, Greece 30 1 42 96 427, Hong Kong 2645 3186, India 91805275406, Israel 03 6120092, Italy 02 41309 1, Japan 03 5472 2970, Korea 02 596 7456, Mexico (D.F.) 5 280 7625, Mexico (Monterrey) 8 357 7695, Netherlands 0348 433466, Norway 32 27 73 00, Poland 48 22 528 94 06, Portugal 351 1 726 9011, Singapore 2265886, Spain 91 640 0085, Sweden 08 58 7 895 00, Switzerland 056 200 51 51, Taiwan 02 2377 1200, United Kingdom 01635 523545

GPIB-232CV-A User Manual D-2 www.ni.com

Page 56

Glossary

Prefix Meaning Value

µ- micro- 10

m- milli- 10

k- kilo- 10

° degrees % percent A amperes AC alternating current ANSI American National Standards Institute ASCII American Standards Code for Information Interchange ATN Attention C Celsius

–6

–3

CIC Controller-In-Charge CR carriage return CSA Canadian Standards Association CTS Clear to Send DAV Data Valid DC direct current DCE Data Circuit-terminating Equipment DIO digital input/output DIP dual inline package DMA direct memory access DTE Data Terminal Equipment DTR Data Terminal Ready

Page 57

Glossary

EIA Electronic Industries Association EMI electromagnetic interference EOI end or identify FCC Federal Communications Commission ggrams GND ground GPIB General Purpose Interface Bus hex hexadecimal Hz hertz IEC International Electrotechnical Commission IEEE Institute of Electrical and Electronic Engineers IFC Interface Clear in. inches KB kilobytes of memory LED light-emitting diode LF linefeed LSI large scale integration m meters oz ounces PC personal computer RAM random-access memory REN Remote Enable ROM read-only memory R TS Request to Send RXD Receive Data s seconds SRQ Service Request

GPIB-232CV-A User Manual G-2 www.ni.com

Page 58

TXD Transmit Data UART Universal Asynchronous Receiver Transmitter UL Underwriters Laboratories V volts VAC volts alternating current VDC volts direct current

Glossary

Page 59

Index

AC front panel, 1-3 application examples, C-1 to C-4

connecting HP7475 GPIB plotter to PC

serial port, C-3 to C-4

using GPIB-232CV-A as high-speed print

spooler, C-1 to C-3

ATN* signal, assertion in D mode, 3-3

buffer size for serial port, choosing, 3-4 BUSY LED (table), 1-5

C mode configuration, 3-7 to 3-11

choosing between D mode and

C mode, 3-1 to 3-2 Controller-in-Charge, 3-7 <CR> or <LF> termination

mode, 3-9 to 3-10 data transfers, 3-7 example of system setup (figure), 3-2 IFC* assertion, 3-7 modes of operation, 3-8 to 3-11 no-swap mode, 3-10 to 3-11 REN* assertion, 3-7 system layout (figure), 3-7 timeout termination mode, 3-8 to 3-9 when to use, 3-2

cables, connecting, 2-7 configuration, 2-1 to 2-6

factory configuration settings, 2-1 location of switches on rear panel

(figure), 1-5 operating at incorrect voltage (caution), 2-1

parameters for SW1 switches

<CR> or <LF> termination

mode, 3-9 to 3-10 default settings for SW1 (figure), 2-2 Listen-only mode setting (figure), 3-6 parameters for SW1 switch 8

(table), 2-4 parameters for SW1 switches

1 through 5 (tab le), 2-2 to 2-4 parameters for SW1 switches 6 and 7

(table), 2-4

serial port parameters

factory default switch settings

(figure), 2-5 SW2 switches 1 through 3

(table),2-5to2-6 SW2 switches 4 through 8 (table), 2-6

conventions used in manual, xi <CR> or <LF> termination mode, C mode

configuration, 3-9 to 3-10

CTS signal, RS-232 port (table), B-2

D mode configuration, 3-3 to 3-6

ATN* signal asserted, 3-3 choosing between D mode and

Cmode,3-1to3-2 choosing serial port buffer size, 3-4 conditions causing SRQ assertion, 3-5 data transfers, 3-3 example of system setup (figure), 3-2 listen-only mode operation, 3-6 maximizing performance with SRQ, 3-5 serial poll responses, 3-6 system layout (figure), 3-3 Talker or Listener mode, 3-3

Page 60

Index

using SRQ feature, 3-4 to 3-5 when to use, 3-1 to 3-2

data buffering and handshaking. See also

handshaking.

hardware handshaking, 3-11 to 3-12 overview, 3-11 XON/XOFF software handshaking, 3-12

Data Communications Equipment (DCE). See

DCE (Data Communications Equipment).

Data Terminal Equipment (DTE). See DTE

(Data Terminal Equipment).

data transfers

C mode, 3-7 D mode, 3-3

DCE (Data Communications Equipment)

interfacing with handshaking, B-3 to B-4

cable configuration for 9-pin DTE

to 9-pin DCE (figure), B-4

cable configuration for 9-pin DTE

to 25-pin DCE (figure), B-4

cable wiring scheme (table), B-3

interfacing without

handshaking, B-4 to B-6

custom cables, B-6 minimum configuration cable, B-5

9-pin DTE to 9-pin DCE

(figure), B-5

9-pin DTE to 25-pin DCE

(figure), B-5

DCL (Device Clear)

command, 3-3 diagnostic resources, online, D-1 documentation

conventions used in manual, xi related documentation, xii

DTE (Data Terminal Equipment)

interfacing with handshaking, B-6 to B-7

cable configuration for 9-pin DTE to

9-pin DTE (figure), B-7

cable configuration for 9-pin DTE to

25-pin DTE (figure), B-7

cable wiring scheme (table), B-6

interfacing without

handshaking, B-7 to B-9

custom cables, B-9 minimum configuration cable, B-8

9-pin DTE to 9-pin DTE

(figure), B-8

9-pin DTE to 25-pin DTE

(figure), B-8

DTR signal, RS-232 port

(table), B-2

electrical characteristics

AC version, A-1 DC version, A-1

environment characteristics

AC version, A-1 to A-2 DC version, A-2

equipment, optional, 1-2

FULL LED (table), 1-5 fuse holder, on AC front panel, 1-3 fuse rating and type, A-1

GET (Trigger) command, 3-3 GND signal, RS-232 port (table), B-2 Go To Local (GTL) command, 3-3 GPIB connector

overview, 1-8 signals supported (figure), 1-8

GPIB-232CV-A User Manual I-2 www.ni.com

Page 61

Index

GPIB-232CV-A. See also operation of

GPIB-232CV-A.

AC front panel, 1-3 GPIB connector, 1-8 inspecting for damage, 1-3 optional equipment, 1-2 overview, 1-1 rear panel, 1-5 requirements for getting started, 1-2 RS-232 connector, 1-7 side panels, 1-6 to 1-8 top panel, 1-4 to 1-5

GTL (Go To Local) command, 3-3

handshaking

DCE (Data Communications Equipment)

interfacing with handshaking,

B-3toB-4

interfacing without handshaking,

B-4toB-6

DTE (Data Terminal Equipment)

interfacing with handshaking,

B-6toB-7

interfacing without handshaking,

B-7toB-9

hardware handshaking, 3-11 to 3-12 overview, 3-11 XON/XOFF software handshaking, 3-12

HP7475 GPIB plotter, connecting to PC serial

port (example), C-3 to C-4

IFC* signal, asserted in C mode, 3-7 installation, 2-6 to 2-8

connecting cables, 2-7 powering on system and switching on

GPIB-232CV-A, 2-8

shutting down your system, 2-6 verifying null-model serial cable, 2-7

LED descriptions (table), 1-4 to 1-5 <LF> termination mode, C mode

configuration, 3-9 to 3-10 LISTEN LED (table), 1-4 Listener, D Mode configuration, 3-3 Listen-only mode

purpose and use, 3-6 switch settings (figure), 3-6

manual. See documentation.

National Instruments Web support, D-1 to D-2 no-swap mode, C mode

configuration, 3-10 to 3-11 null-modem serial cable

National Instruments null-modem serial

cables (table), 2-7

verifying during installation, 2-7

online problem-solving and diagnostic

resources, D-1 operation of GPIB-232CV-A, 3-1 to 3-12

C mode overview, 3-7 to 3-11 choosing between D mode and

Cmode,3-1to3-2 D mode overview, 3-3 to 3-6 data buffering and handshaking

schemes, 3-11 to 3-12

Page 62

Index

physical characteristics

AC version, A-2 DC version, A-2

plotter, GPIB, connecting to PC serial port

(example), C-3 to C-4 POWER LED (table), 1-4 print spooler, high speed, using

GPIB-232CV-A as (example), C-1 to C-3 problem-solving and diagnostic resources,

online, D-1

READY LED

checking during first power-on, 2-8

description (table), 1-4 rear panel, 1-5 REN* signal, asserted in C mode, 3-7 requirements for getting started, 1-2 RS-232 serial port

buffer size selection in D mode, 3-4

configuration parameters

factory default settings (figure), 2-5 SW2 switches 1 through 3

(table),2-5to2-6

SW2 switches 4 through 8

(table), 2-6

interfacing serial devices, B-2 to B-9

location of RS-232 connector

(figure), B-3

to DCE with handshaking,

B-3toB-4

to DCE without handshaking,

B-4toB-6 to DTE with handshaking, B-6 to B-7 to DTE without handshaking,

B-7toB-9

overview, 1-7

RS-232C standard for, B-1 signal configuration (table), B-2

signals supported (figure), 1-7 RTS signal, RS-232 port (table), B-2 RXD signal, RS-232 port (table), B-2

SDC (Selected Device Clear) command, 3-3 serial cable, null-modem, 2-7 serial poll response of GPIB-232CV-A, 3-6 serial port. See RS-232 serial port. side panels, 1-6 to 1-8

GPIB connector, 1-8

location of connectors and DC power jack

(figure), 1-6

RS-232 connector, 1-7 software-related resources, D-2 specifications

electrical characteristics

AC version, A-1 DC version, A-1

environment characteristics

AC version, A-1 to A-2 DC version, A-2

physical characteristics

AC version, A-2 DC version, A-2

SRQ feature

conditions causing assertion of SRQ, 3-5

enabling, 3-4

maximizing performance with SRQ, 3-5

purpose and use, 3-4 switches. See configuration.

TALK LED (table), 1-4 Talker, D Mode configuration, 3-3 technical support resources, D-1 to D-2

GPIB-232CV-A User Manual I-4 www.ni.com

Page 63

Index

timeout termination mode, C mode

configuration, 3-8 to 3-9

top panel, 1-4 to 1-5

illustration, 1-4

LED descriptions (table), 1-4 to 1-5 Trigger (GET) command, 3-3 TXD signal, RS-232 port (table), B-2

Web support from National Instruments,

D-1toD-2

online problem-solving and diagnostic

resources, D-1

software-related resources, D-2

Worldwide technical support, D-2

National Instruments GPIB-232CV-A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

GPIB-232CV-A User Manual

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Contents

Figures

Tables

About This Manual

Conventions

Related Documentation

GPIB-232CV-A Overview

What You Need to Get Started

Optional Equipment

Inspection

GPIB-232CV-A Panels

AC Front Panel

Top Panel

Rear Panel

Side Panels

RS-232 Connector

GPIB Connector

Configure Your Hardware

Configure the GPIB-232CV-A Parameters

Table 2-2. Configuration Parameters for SW1 Switches 6 and 7

Table 2-3. Configuration Parameters for SW1 Switch 8

Configure the Serial Port Parameters

Install Your Hardware

Step 1. Shut Down Your System

Step 2. Verify That You Have a Null-Modem Serial Cable

Step 3. Connect the Cables

Choosing Between D Mode and C Mode Configuration

When to Use D Mode

When to Use C Mode

Figure 3-1. Example of D Mode System Setup

Figure 3-2. Example of C Mode System Setup

D Mode Overview

Data Transfers in D Mode

Choosing a Serial Port Buffer Size

Using the SRQ Feature

Conditions That Cause SRQ to be Asserted

Maximizing Performance with SRQ

GPIB-232CV-A Serial Poll Responses

GPIB-232CV-A Operation in Listen-Only Mode

C Mode Overview

Data Transfers in C Mode

Modes of Operation Within C Mode

Timeout Termination Mode

<CR> or <LF> Termination Mode

No-Swap Mode

Data Buffering and Handshaking Schemes

Hardware Handshaking

XON/XOFF Software Handshaking

Figure B-1. Location of the RS-232 Connector

Table B-2. Cable Wiring Scheme for GPIB-232CV-A DTE to Serial Device DCE

Figure B-2. Cable Configuration for 9-pin DTE to 9-pin DCE with Handshaking

Figure B-3. Cable Configuration for 9-pin DTE to 25-pin DCE with Handshaking

Figure B-6. Cable Configuration for 9-pin DTE to 9-pin DTE with Handshaking

Figure B-7. Cable Configuration for 9-pin DTE to 25-pin DTE with Handshaking

Figure C-1. Example of Print Spooler Setup

Glossary

Index