GPIB-232CV User Manual
Contents
1. GPIB 232CV User Manual 1 6 National Instruments Corp Chapter 1 Description of the GPIB 232CV The GPIB Connector The GPIB connector is a standard 24 pin shielded AMP Champ female connector with metric screwlock hardware A diagram of the GPIB connector and the signals supported is shown in Figure 1 5 a suffix indicates that the signal is active low Je 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 Figure 1 5 The GPIB Connector and Signal Designations National Instruments Corp 1 7 GPIB 232CV User Manual Chapter 2 Configuration and Installation This chapter describes the procedures for configuring and installing the GPIB 232CV As mentioned in Chapter 1 the GPIB 232CV can be configured either as a GPIB Controller capable of addressing a single GPIB device to talk or listen or as a GPIB device that can be addressed to talk or listen by a GPIB Controller Choosing Between D Mode or C Mode When transferring data to or from a GPIB device that has no controller capabilities the GPIB 232CV should be set to operate in the Controller C mode This is because in a GPIB system there must exist at least one Controller that is responsible for addressing the instruments on the bus to talk and listen In this mode the GPIB 232CV upo2. Global Engineering Documents 2805 McGaw Avenue Irvine CA 92714 714 261 1455 The RS 232C Serial Port The RS 232 serial port on the GPIB 232CV uses a female 25 pin D subminiature connector with a DTE Data Terminal Equipment interface configuration That is the GPIB 232CV transmits data on pin 2 and receives data on pin 3 Table B 1 shows the signal lines supported on the GPIB 232CV National Instruments Corp B 1 GPIB 232CV User Manual Interfacing to a Serial Device Appendix B Table B 1 RS 232 Serial Port Signals This line is connected to the chassis Protective ground of the GPIB 232CV Since Ground the chassis ground is not connected to earth ground pin should be connected on both serial devices This line carries serial data from the Transmit Data GPIB 232CV to the serial host This line carries serial data from the Receive Data serial host to the GPIB 232CV RTS This signal line is driven by the Request to GPIB 232CV and when asserted Send indicates that the GPIB 232CV is ready to accept serial data The GPIB 232CV unasserts RTS when it is no longer ready to accept serial data because the buffer is full CTS This signal line is asserted by the Clear to Send serial host and sensed by the GPIB 232CV When asserted it indicates that the serial host is ready to accept serial data When unasserted it indicates that data transmission should be disabled AB 7 SG This line establishe
3. nl tn nn hs 2 9 Configuration Parameters for U20 Switches GO through Seii nt SR em CRC RUE nn 2 9 Electrical Characteristics 0 0 0 cece cesceceeseeeeeeeeeeseseeeeeens A 1 Environmental Characteristics A 1 Physical Characteristics esesseeeseseeeesseeesseeeresrserressrrereee A 2 RS 232 Serial Port Signals B 2 National Instruments Corp ix GPIB 232CV User Manual About This Manual The GPIB 232CV User Manual describes the features functions and operation of the Product The GPIB 232CV is one of National Instruments family of MicroGPIB products These products are high performance low cost IEEE 488 support items packaged in small all metal cases capable of being rack mounted Organization of This Manual The GPIB 232CV User Manual is organized as follows Chapter 1 Description of the GPIB 232CV contains a brief overview of the GPIB 232CV lists the contents of your kit and optional equipment and describes the panels of the GPIB 232CV Chapter 2 Configuration and Installation describes the procedures for configuring and installing the GPIB 232CV Chapter 3 Operation contains information about operating the GPIB 232CV in D mode or C mode and information about data buffering and handshaking Appendix A Hardware Specifications lists the electrical environmental and physical specifications of the GPIB 232CV Appendix B Int
4. Power on the Unit Power on your GPIB 232CV by using the front panel rocker switch The POWER LED should come on immediately The READY indicator should come on after the GPIB 232CV has passed its power on self test indicating the unit is ready for operation If the READY indicator 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 light still fails to come on contact National Instruments for further instructions Operation The GPIB 232CV is now ready to operate All characters sent to the unit will be received at full speed and stored in the internal data buffer The characters will be sent to the receiving device at the rate of the receiving device If using the GPIB 232CV in C mode turn on the GPIB instrument before turning on the GPIB 232CV and be sure the configuration switches are set correctly When the GPIB 232CV is powered on it will send IFC and address the instrument to listen Simply send data to your serial port as you GPIB 232CV User Manual 2 10 National Instruments Corp Chapter 2 Configuration and Installation would if you had a serial device connected to it and the data will be converted and sent to the GPIB instrument When the instrument has data to send back the GPIB 232CV will address the instrument to talk and pass all received data to the RS 232 port If using the GPIB 232CV in D mode simply addr
5. KB RAM 115 VAC 776174 02 e GPIB 232CV 256 KB RAM 230 VAC 776174 32 GPIB 232CV User Manual 320109 01 GPIB 232CV User Manual 1 2 National Instruments Corp Chapter 1 Description of the GPIB 232CV Optional Equipment Rack mount Kit Single 1 unit 180480 01 Dual 2 units 180480 02 RS 232 Shielded Cable Compatible with IBM PC DTE to DTE 1m 181074 10 25 pin male D sub to 9 pin female D sub Double Shielded GPIB Cables GPIB Type X2 Cable 1 m 763061 01 GPIB Type X2 Cable 2 m 763061 02 GPIB Type X2 Cable 4 m 763061 03 The GPIB 232CV Front Panel The front panel of the GPIB 232CV is shown in Figure 1 2 The power switch and six light emitting diodes LEDs are mounted on the GPIB 232CV front panel QKI INSTRUMENTS GPIB 232CV p IEEE 488 RS 232 CONVERTER POWER READY TALK LISTEN BUSY FULL Figure 1 2 The GPIB 232CV Front Panel National Instruments Corp 1 3 GPIB 232CV User Manual Description of the GPIB 232CV Chapter 1 The LEDs show the current status of the GPIB 232CV at all times Table 1 1 describes each LED Table 1 1 LED Descriptions POWER Indicates that power to the unit has been applied and the ON OFF switch is in the ON position READY Indicates that the power on self test has passed successfully and the unit is ready to operate TALK Indicates that the GPIB 232CV is configured as a GPIB Talker LISTEN Indicates that the GPIB 232CV is configured
6. and the hardware handshaking protocols The hardware handshake is always active during RS 232 transfers The XON XOFF protocol is enabled or disabled by properly setting the internal configuration switch Hardware Handshake The hardware handshake function is always active during RS 232 transfers and uses the RTS and CTS signal lines When the GPIB 232CV is ready to accept serial data it asserts the RTS line This signal remains asserted until the GPIB 232CV s data buffer is almost full At this point the GPIB 232CV unasserts the RTS line signaling to the serial host that the GPIB 232CV 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 is also able to suspend transmission when the serial host is no longer ready to accept data The GPIB 232CV is configured to immediately stop transmission of serial data when CTS becomes unasserted Note If you use a serial cable that does not connect to CTS CTS will not be asserted and the GPIB 232CV will not transmit data GPIB 232CV User Manual 3 8 National Instruments Corp Chapter 3 Operation XON XOFF If your serial device does not recognize the hardware handshake scheme or if your application software uses the XON XOFF handshake scheme it may be necessary to enable the XON XOFF handshaking protocol This handshaking protocol performs the same function as the hardware handsh
7. and the GPIB port are interrupt driven and feature extremely fast response times to external data transfers For more information on how the individual modes of operation work refer to the following discussions The following terms are specific to the discussions in this chapter e A suffix after a mnemonic indicates negative logic e A boldface mnemonic indicates that it is a signal name or a front panel LED indicator e lt CR gt is the symbol for the Carriage Return character hex OD e lt LF gt is the symbol for the Linefeed character hex OA National Instruments Corp 3 1 GPIB 232CV User Manual Operation Chapter 3 D Mode Operation In D mode the GPIB 232CV can act only as a GPIB Talker or Listener The GPIB 232CV should not be passed control If it is the GPIB circuitry in the GPIB 232CV will accept control and immediately assert ATN This is an error condition that can lock up your system and should therefore be avoided Data Transfers and Buffering When operating in D mode the GPIB 232CV accepts data from the GPIB port using the onboard DMA Controller The DMA Controller transfers the data directly to the memory buffer without processor intervention As a result very high speed GPIB transfer rates are possible as high as 900 kbytes sec This means that the GPIB system performance will not be degraded by connecting a slow printer or plotter to the interface The buffered data is then dumped to the devic
8. as a GPIB Listener BUSY Indicates that the GPIB 232CV is currently accepting serial data Each serial character received toggles the status of the BUSY LED FULL Indicates that one of the GPIB 232CV 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 interface GPIB 232CV User Manual 1 4 National Instruments Corp Chapter 1 Description of the GPIB 232CV The GPIB 232CV Rear Panel The power cord serial cable and GPIB cable connections are on the rear panel Figure 1 3 shows the rear panel of the GPIB 232CV Figure 1 3 The GPIB 232CV Rear Panel National Instruments Corp 1 5 GPIB 232CV User Manual Description of the GPIB 232CV Chapter 1 The RS 232 Connector The RS 232 port on the GPIB 232CV is configured as a DTE Data Terminal Equipment and uses a standard 25 pin shielded D subminiature female connector with screwlock assemblies The RS 232 connector will accept standard 25 pin D subminiature male connectors A diagram of the serial connector and the signals supported is shown in Figure 1 4 For more information on the RS 232 signals refer to Appendix B Interfacing to a Serial Device 6 OT IT ET ET 8 9 N UI N D N Ww N N N fan N m Ne bi ee H ji OD m Oo I ws O O O O O O OO O O OO OO O O O O O O OO OOO0O0o0o00 O L Figure 1 4 The RS 232 Connector and Signal Designations
9. for your application review your serial device s RS 232 characteristics and build the cable to perform the desired functions GPIB 232CV User Manual B 6 National Instruments Corp Appendix C Application Examples This appendix contains two GPIB 232CV application examples The first example shows how to use the GPIB 232CV 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 as a High Speed Print Spooler Because mechanical printers and plotters are slow relative to the processing speed of a computer computers must output data at a slow 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 Standard print spoolers are able to store incoming data in a RAM buffer until the printer or plotter is able to accept it allowing the PC to output data at a rate faster than printer or plotter rates You can use the GPIB 232CV in this way With a GPIB 232CV you can transfer data at GPIB rates instead of RS 232 rates The GPIB 232CV uses a DMA Controller to input data from the GPIB port to the RAM buffer and can input GPIB data at rates up to 900 kbytes sec Therefore the transfer rate is limited only by the rate at which the GPIB Talker can write data This example sh
10. 32CV configuration switches Set the serial port parameters to XON XOFF disabled 9600 baud 7 data bits 1 stop bit and even parity 3 Power on the plotter then power on the GPIB 232CV When the GPIB 232CV is powered on it addresses the GPIB plotter Any data sent to the serial port by AUTOCAD is received by the GPIB 232CV and stored in its internal buffer The GPIB 232CV transfers the data to the plotter over the GPIB connection as fast as the plotter can receive it Because the GPIB 232CV 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 User Manual C 4 National Instruments Corp Appendix D Customer Communication For your convenience this appendix contains forms to help you gather the information necessary to help us solve technical problems you might have as well as a form you can use to comment on the product documentation Filling out a copy of the Technical Support Form before contacting National Instruments helps us help you better and faster National Instruments provides comprehensive technical assistance around the world In the U S and Canada applications engineers are available Monday through Friday from 8 00 a m to 6 00 p m central time In other countries contact the nearest branch of
11. AGONE EU da 3 1 D Mode Operation sssrinin es arri a 3 2 Data Transfers and Buffering 200 0 ee eee eee eee 3 2 Choosing a Serial Port Buffer Size ee 3 2 Using the SRQ Feature eee ec eeeeeeeseeeseeneeenee 3 3 Enabling the SRQ Feature 3 3 Conditions that Assert SRQ ceeeeeeeee 3 4 Serial Poll Responses 0 0 cesses ceeceeceeceseeeeeesees 3 4 Listen Only Mode ssh iiris 3 4 National Instruments Corp vil GPIB 232CV User Manual Contents Special Conditions in D Mode 1 0 eee 3 5 C Mode Operation Less nimes nuits RIRE ions 3 5 Modes of Operation within C Mode eee 3 5 Time Termination Mode eee 3 6 lt CR gt or lt LF gt Termination Mode 3 6 No Swap Mode 3 7 Buffering and Handshaking 00 eee eee eeeeseceeeteceeeeseeneees 3 8 Hardware Handshake ee eeeecceeeeeeceeeeeeeeeeeeeens 3 8 XON XOPF sun s at dm TA at dites 3 9 Appendix A Hardware Specifications A 1 Appendix B Interfacing to a Serial Device o 0 0 00 cece eeeteeeeee B 1 The RS 232C Standard 4 Erts B 1 Th RS 232C Serial Ports i i oe fcc testes acest ene B 1 Interfacing the GPIB 232CV to a DCE ou eteeeeeeee B 3 Interfacing the GPIB 232CV to a DTE oo eeee B 5 Appendix C Application Examples C 1 Using the GPIB 232CV as a High Speed Print Spooler C 1 Using the GPIB 232CV to Connect a HP7475 GPIB Plotter to a PC Serial Port ieee ee eeceeeeeeeeeece
12. F ON positions respectively this indicates a GPIB primary address of 5 Tables 2 1 2 2 and 2 3 show the possible configurations of the eight switches and what the configurations indicate GPIB 232CV User Manual 2 4 National Instruments Corp Chapter 2 Configuration and Installation Default settings are in shaded rows Table 2 1 Configuration Parameters for U22 Switch 1 Switch 1 Indication Position GPIB 232CV operates in D mode GPIB 232CV operates in C mode Table 2 2 Configuration Parameters for U22 Switches 2 and 3 Switches Indication 2 3 C Mode Small serial buffer and Time out termination disable SRQ Small serial buffer and CR termination enable SRQ Large serial buffer and LF termination disable SRQ Large serial buffer and No swapping enable SRQ National Instruments Corp 2 5 GPIB 232CV User Manual Configuration and Installation Chapter 2 Table 2 3 Configuration Parameters for U22 Switches 4 through 8 Switches Indication 6 7 8 GPIB Primary Address 0 GPIB Primary Address 1 GPIB Primary Address 2 GPIB Primary Address 3 GPIB Primary Address 4 GPIB Primary Address 5 GPIB Primary Address 6 GPIB Primary Address 7 GPIB Primary Address 8 GPIB Primary Address 9 GPIB Primary Address 10 GPIB Primary Address 11 GPIB Primary Address 12 GPIB Primary Address 13 GPIB Primary Address 14 GPIB Primary Address 15 GPIB Primary Address 16 GPIB Primary Address 17 GPIB Primary Address 18 GPIB Pri
13. GPIB 232CV User Manual IEEE 488 lt RS 232 Converter April 1994 Edition Part Number 320109 01 Copyright 1987 1994 National Instruments Corporation All Rights Reserved National Instruments Corporate Headquarters 6504 Bridge Point Parkway Austin TX 78730 5039 512 794 0100 Technical support fax 512 794 5678 Branch Offices Australia 03 879 9422 Austria 0662 435986 Belgium 02 757 00 20 Canada Ontario 519 622 9310 Canada Qu bec 514 694 8521 Denmark 45 76 26 00 Finland 90 527 2321 France 1 48 65 33 70 Germany 089 714 50 93 Italy 02 48301892 Japan 03 3788 1921 Netherlands 01720 45761 Norway 03 846866 Spain 91 640 0085 Sweden 08 730 49 70 Switzerland 056 27 00 20 U K 0635 523545 Limited Warranty The GPIB 232CV is warranted against defects in materials and workmanship for a period of two years from the date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace equipment that proves to be defective during the warranty period This warranty includes parts and labor A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this manual is ac
14. IB 232CV to listen and allow other devices to use the GPIB When the GPIB 232CV has emptied out its GPIB input buffer it will request service indicating it is ready for more data The Controller can then re address the GPIB 232CV to listen and continue sending data in the manner described until all the data has been sent Enabling the SRQ Feature The SRQ feature can be enabled by setting switch 3 of the configuration switch at location U22 to the ON position When enabled the GPIB 232CV will assert the SRQ signal whenever either the GPIB input buffer becomes empty or the GPIB 232CV receives serial data that it needs to pass on to the GPIB port SRQ will be unasserted when the GPIB Controller performs a serial poll on the GPIB 232CV National Instruments Corp 3 3 GPIB 232CV User Manual Operation Chapter 3 Conditions that Assert SRQ When the SRQ feature is enabled one of the conditions that causes a service request is when the GPIB 232CV serial input buffer is empty Then the GPIB 232CV receives a serial character to be sent along to the GPIB The SRQ signal is asserted to alert the GPIB Controller that the GPIB 232CV has data to send to a GPIB Listener The GPIB 232CV can then be addressed to talk so that the data can be read out of the GPIB 232CV serial buffer After all data has been read the Controller can unaddress the GPIB 232CV to talk so that other devices can be addressed to transfer data on the bus The other conditi
15. IB address switches are set to ON In the listen only mode no addressing is required to make the GPIB 232CV a GPIB Listener and it cannot be unaddressed to listen All data transferred on the GPIB will be accepted by the GPIB 232CV and output to the serial port even if the data GPIB 232CV User Manual 3 4 National Instruments Corp Chapter 3 Operation was intended for another device This configuration could be used to monitor all GPIB data bus activity Notice that when the GPIB 232CV is configured as a listen only device it may not be serial polled Special Conditions in D Mode If the GPIB 232CV receives the universal Device Clear DCL command or its listen address and the Selected Device Clear SDC command the GPIB 232CV will clear its internal data buffers and reset to its power up state Neither Trigger nor Go To Local has any effect on the GPIB 232CV In D mode operation the GPIB 232CV does not assert EOI when sending characters along to the GPIB You can use bit of the serial poll response byte to determine if there are characters waiting to be sent to the GPIB C Mode Operation In C mode the GPIB 232CV acts as the GPIB System Controller and asserts IFC for 500 us when the GPIB 232CV is powered on The action of asserting IFC for at least 100 us initializes the GPIB and makes the System Controller Controller In Charge CIC After the GPIB 232CV becomes CIC it sends out the GPIB listen address on U22 switches 4 thr
16. ake but does so by sending special control codes over the data lines instead of by changing logic levels on dedicated control lines When you enable the XON XOFF protocol the GPIB 232CV sends the XOFF character decimal 19 or lt CTRL gt s when its internal buffer becomes full Once the GPIB 232CV is able to start receiving characters again it sends the XON character decimal 17 or lt CTRL gt q Similarly if the GPIB 232CV is transmitting data and receives the XOFF character it suspends transmission of any further data until it receives the XON character Caution Do not use XON XOFF handshaking if you are transmitting binary data Because your data could include decimal 17 or 19 lt CTRL gt q or lt CTRL gt s the GPIB 232CV might handshake erratically National Instruments Corp 3 9 GPIB 232CV User Manual Appendix A Hardware Specifications This appendix lists the electrical environmental and physical specifications of the GPIB 232CV Table A 1 Electrical Characteristics Characteristic Specification Power Supply Unit Wall mount type 115 VAC or 230 VAC 50 60 Hz input 9 VDC 1A max output 640 mA typical 750 mA max Table A 2 Environmental Characteristics Characteristic Specification Operating Temperature 10 to 40 C Storage Temperature 0 to 70 C Relative Humidity 10 to 95 noncondensing conditions Noise Emissions FCC Class A Verified National Instruments Corp A 1 GPIB 232CV User M
17. alfunctions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation Trademarks Product and company names listed are trademarks or trade names of their respective companies Warning Regarding Medical and Clinical Use of National Instruments Products National Instruments products are not designed with components and testing intended to ensure a level of reliability suitable for use in treatment and diagnosis of humans Applications of National Instruments products involving medical or clinical treatment can create a potential for accidental injury caused by product failure or by errors on the part of the user or application designer Any use or application of National Instruments products for or involving medical or clinical treatment must be performed by properly trained and qualified medical personnel and all traditional medical safeguards equ
18. anual Hardware Specifications Appendix A Table A 3 Physical Characteristics Case Size 1 6 in by 5 7 in by 8 4 in 40 6 mm by 144 8 mm by 213 4 mm Rack Mounting Single or dual kits available 28 oz without power supply unit GPIB 232CV User Manual A 2 National Instruments Corp Appendix B Interfacing to a Serial Device This appendix contains information about the RS 232 port and how to connect the GPIB 232CV to your serial device This information is useful if you want to build your own serial cable The GPIB 232CV transfers serial data using the electrical signals the mechanical connections and the data format and control protocols as defined in the RS 232C standard The RS 232 port on the GPIB 232CV provides an asynchronous serial communication link to the host serial peripheral device The RS 232 connector is located on the rear panel of the GPIB 232CV The 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 EJA 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 232 standard contact
19. be done with the following commands GPIB 232CV User Manual 3 6 National Instruments Corp Chapter 3 Operation 10 OPEN COM1 9600 n 8 1 AS 1 Assumes GPIB 232CV is at 9600 baud no parity 8 data bits 1 stop bit 20 PRINT 1 pal000 1000 os Plot absolute to 1000 1000 then output status 30 LINE INPUT 1 RESPONSES Get status response from plotter 40 PRINT 1 ci100 Draw circle with radius of 100 units Notice that on line 20 the program outputs plotter commands to the serial port to both draw a line and obtain status Since neither a lt CR gt nor lt LF gt was sent between these commands the GPIB 232CV will keep the GPIB plotter addressed to listen and will send all serial data received to the plotter Since the PRINT statement is not ended with a semicolon after the double quotation mark BASIC will automatically send a lt CR gt after the last character in the ASCII string has been sent Therefore if the GPIB 232CV is set up for lt CR gt termination the GPIB 232CV would at this time re address the plotter to talk so that the status could be output Line 30 will input the status response from the plotter into a string variable RESPONSES Line 40 will then output the plotter command to draw a circle to the GPIB 232CV As soon as the GPIB 232CV receives the first character in this string it will re address the plotter to listen before sending these characters to the plotter Not
20. curate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition The reader should consult National Instruments if errors are suspected In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONALINSTRUMENTS 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 This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects m
21. e if selected serial data GPIB 232CV User Manual 3 2 National Instruments Corp Chapter 3 Operation will not be lost regardless of the serial buffer size you choose The larger serial buffer size is simply provided as a means of capturing a larger percentage of the total RAM space for serial input use For example if you were connecting an RS 232 device capable only of transmitting data to the GPIB 232CV you would definitely want to use the 32 KB serial buffer to maximize the use of the available RAM space Using the SRQ Feature If your GPIB system has GPIB devices other than the GPIB 232CV that need to transfer data and it is important that the GPIB bus not be slowed down or hung waiting for the GPIB 232CV to either receive serial data to be passed along to the GPIB or accept more GPIB data because its GPIB input buffer is full then the SRQ feature can be enabled The SRQ feature will alert the GPIB Controller by asserting the GPIB signal SRQ when the GPIB 232CV requires attention The Controller can then determine the status of the GPIB 232CV by performing a serial poll and analyzing the response byte In this way the GPIB bus can be used by other devices until service is required by the GPIB 232CV To get maximum GPIB performance when very large amounts of data are sent to the GPIB 232CV enable the SRQ feature and only send data amounts up to but not exceeding the GPIB input buffer size The Controller can then unaddress the GP
22. e on the RS 232 port at its own rate These two asynchronous events take place concurrently and without user interaction All operations are completely transparent to the user Any serial data that is sent to the GPIB 232CV will be buffered and then passed along to the GPIB port whenever the GPIB 232CV is addressed to talk Depending upon how much data if any is expected to be sent to the GPIB 232CV via the serial port two different serial port input buffer sizes can be used for maximum efficiency The size of the serial input buffer can be set to either 256 bytes U22 switch 2 set to OFF or 32 KB U22 switch 2 set to ON The serial input buffer size should be set to 256 bytes if only small amounts of data such as status information are expected to be sent from the serial device to the GPIB 232CV The serial input buffer size should probably be set to 32 KB if large amounts of data are expected to be sent from the serial device to the GPIB 232CV such as an RS 232 instrument sending thousands of bytes of measurements Choosing a Serial Port Buffer Size Whether you use a 256 byte or 32 KB buffer size the remainder of the 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 it would be advantageous to use the small serial port buffer size if possible Remember that because the GPIB 232CV implements a hardware handshake scheme as well as the XON XOFF software handshake schem
23. eeseeenecsaeeaes C 4 Appendix D Customer Communication D 1 GIOSS ATV ese ONS ORG SAG Cnet ete G 1 GPIB 232CV User Manual viii National Instruments Corp Figure 1 1 Figure 1 2 Figure 1 3 Figure 1 4 Figure 1 5 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure B 1 Figure B 2 Figure B 3 Figure B 4 Figure C 1 Table 1 1 Table 2 1 Table 2 2 Table 2 3 Table 2 4 Table 2 5 Table A 1 Table A 2 Table A 3 Table B 1 Contents Figures The GPIB 232CV sin hareng 1 1 The GPIB 232CV Front Panel 1 3 The GPIB 232CV Rear Panel 1 5 The RS 232 Connector and Signal Designations 1 6 The GPIB Connector and Signal Designations 1 7 Example of C Mode System Setup 2 1 Example of D Mode System Setup 2 2 Factory Default Settings for Switch U22 2 4 Factory Default Settings for Switch U20 2 8 DTE to DCE Cable Configuration 00 0 eee B 3 Minimum DTE to DCE Cable Configuration 0 0 B 4 Null Modem Cable Configuration 00 0 0 ceeeeeeeeereeee B 5 Minimum Null Modem Cable Configuration B 6 Example of Print Spooler Setup C 2 Tables LED Descriptions 1 4 Configuration Parameters for U22 Switch 1 oo 2 5 Configuration Parameters for U22 Switches 2 and 3 2 5 Configuration Parameters for U22 Switches A throug 8 sess sise tn terne etes 2 6 Configuration Parameters for U20 Switches TV through Sin
24. er the FCC Rules If necessary consult National Instruments or an experienced radio television technician for additional suggestions The following booklet prepared by the FCC may also be helpful How to Identify and Resolve Radio TV Interference Problems This booklet is available from the U S Government Printing Office Washington DC 20402 Stock Number 004 000 00345 4 Contents About This Manual Organization of This Manual 0 cece eee cee ceseesecnseeeeeneees xi Conventions Used in This Manual xii Related Documentation xiii Customer Communication xiii Chapter 1 Description of the GPIB 232CV 0 0 0 c cccccccee eects 1 1 TnTTOdUCHOME se EE 1 1 What Your Kit Contains eee eeeeeeeeeeeeeseeeseeseecneesaeenes 1 2 Optional Equipment ss 1 3 The GPIB 232CV Front Panel 1 3 The GPIB 232CV Rear Panel 1 5 The RS 232 Connector 1 6 The GPIB Connector eresi caste eect se 1 7 Chapter 2 Configuration and Installation 2 000 000 0000 eee 2 1 Choosing Between D Mode or C Mode 2 1 Installation terre est Rent nadie 2 2 Step 1 Inspection sus sites ns oases 2 3 Step 2 Verify the Voltage Requirement 2 3 Step 3 Configure the Operating Parameters 2 3 Set Configuration Switches 2 4 Step 4 Connect the Cables 2 10 Step 5 Power on the Unit 2 10 Operatiohsssnsisnnsenmoninnntihetetinne ttes nus 2 10 Chapter 3 ODRF
25. erfacing to a Serial Device contains information about the RS 232 port and how to connect the GPIB 232CV to your serial device This information is useful if you want to build your own serial cable Appendix C Application Examples contains an example showing how to use a GPIB 232CV as a high speed print spooler and an example showing how to use a GPIB 232CV to interface a HP7475 plotter to a computer running AUTOCAD Appendix D Customer Communication contains forms you can use when requesting help from National Instruments or to comment on our products and manuals National Instruments Corp xi GPIB 232CV User Manual About This Manual e The Glossary contains an alphabetical list and description of terms used in this manual including abbreviations acronyms metric prefixes mnemonics and symbols Conventions Used in This Manual The following conventions are used in this manual italic Italic text denotes emphasis a cross reference or an introduction to a key concept monospace Text in this font denotes text or characters that are to be literally input from the keyboard sections of code programming examples syntax examples and names of variables bold Bold text in this manual denotes a signal name or a front panel LED indicator lt gt Angle brackets enclose the ASCII character symbols for certain keystrokes For example lt CR gt for carriage return and lt LF gt for linefeed A hyphen between two or m
26. es of the rear panel 3 Grab the rear panel bezel and pull it straight away from the rest of the unit The card should slide out the back of the enclosure 4 Locate the configuration DIP switches U20 and U22 on the printed wire board 5 Set the switches for the desired mode of operation as described in the following section Set Configuration Switches National Instruments Corp 2 3 GPIB 232CV User Manual Configuration and Installation Chapter 2 Warning Most of the circuitry in the GPIB 232CV uses advanced CMOS technology and can be damaged by static electricity Avoid touching any of the components and take any necessary CMOS handling precautions 6 Close the unit and re insert the screws removed in Step 2 Set Configuration Switches The DIP switches at location U20 and U22 on the printed wire board are used to configure the GPIB 232CV The DIP switch at location U22 is used to configure the mode of the GPIB 232CV as well as the address of the GPIB device The DIP switch shown in Figure 2 3 has eight configuration switches TEC Figure 2 3 Factory Default Settings for Switch U22 Figure 2 3 shows the GPIB 232CV s factory default settings for switch U22 Switch 1 is in the OFF position this indicates that the unit is configured to operate in D mode Switches 2 and 3 are in the OFF position this indicates that SRQ is disabled and the small serial buffer is selected Switches 4 through 8 are in the OFF OFF ON OF
27. ess the GPIB 232CV to listen if not in listen only mode when you have data to send All GPIB data received by the GPIB 232CV will be buffered and passed along to the serial device When you are expecting data from the serial device address the GPIB 232CV to talk and all data received over the serial port will then be passed along to the GPIB National Instruments Corp 2 11 GPIB 232CV User Manual Chapter 3 Operation This chapter contains information about operating the GPIB 232CV in D mode or C mode and information about data buffering and handshaking The GPIB 232CV is actually a powerful 8 bit microcomputer tailored for use as an IEEE 488 to RS 232 protocol converter The unit s operating system is contained in Read Only Memory ROM and can address up to 256 KB of dynamic Random Access Memory RAM The GPIB 232CV microprocessor contains an integrated Direct Memory Access DMA Controller for high speed data transfers from the GPIB circuitry The processor also 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 The serial port has been designed to be fully compatible with all electrical specifications in the RS 232 standard All GPIB functionality is provided by an LSI GPIB Controller chip which is programmed and maintained by the operating system Both the serial port
28. fice You may fax questions to us at any time Corporate Headquarters 512 795 8248 Technical Support fax 512 794 5678 Branch Offices Phone Number Fax Number Australia 03 879 9422 03 879 9179 Austria 0662 435986 0662 437010 19 Belgium 02 757 00 20 02 757 03 11 Denmark 45 76 26 00 45 7671 11 Finland 90 527 2321 90 502 2930 France 1 48 65 33 00 1 48 65 19 07 Germany 089 7 14 50 93 089 7 14 60 35 Italy 02 48301892 02 48301915 Japan 03 3788 1921 03 3788 1923 Netherlands 01720 45761 01720 42140 Norway 03 846866 03 846860 Spain 91 640 0085 91 640 0533 Sweden 08 730 49 70 08 730 43 70 Switzerland 056 27 00 20 056 27 00 25 UK 0635 523545 0635 523154 or 0800 289877 in U K only National Instruments Corp D 1 GPIB 232CV User Manual Technical Support Form Photocopy this form and update it each time you make changes to your software or hardware and use the completed copy of this form as a reference for your current configuration Completing this form accurately before contacting National Instruments for technical support helps our applications engineers answer your questions more efficiently If you are using any National Instruments hardware or software products related to this problem include the configuration forms from their user manuals Include additional pages if necessary Name Company Address Fax Computer brand Phone Model Operating system Processor S
29. ice that for this PRINT statement a semicolon was included after the last double quotation mark so that a lt CR gt will not be sent Since information was not requested from the plotter there is no need to send a lt CR gt at the end of the string to address the plotter to talk No Swap Mode In the last mode no swap the GPIB 232CV will never re address the GPIB device after it has initially addressed it to be a Listener This mode is useful if your GPIB device is intended only to receive data In the above example you could use the no swap mode to talk to the plotter if you never need to obtain status information from it National Instruments Corp 3 7 GPIB 232CV User Manual Operation Chapter 3 Buffering and Handshaking Two protection mechanisms are used to ensure that the GPIB 232CV does not lose incoming serial data data buffering and handshaking The GPIB 232CV has an internal RAM buffer that stores incoming serial data until it can output the data to the GPIB port The size of this RAM buffer in part determines how much serial data the GPIB 232CV can accept until its buffer overflows The GPIB 232CV comes equipped with a 256 KB RAM buffer When its RAM buffer is nearly full the GPIB 232CV can handshake with the serial host to stop data transmission When the buffer is almost empty the GPIB 232CV can again handshake with the serial host to start data transmission The GPIB 232CV is capable of using both the XON XOFF
30. ight have data that it needs to send back to the GPIB 232CV Any characters read from the GPIB port at this time will immediately be passed along to the serial port When a serial character is received by the GPIB 232CV it immediately re addresses the GPIB device to listen and passes the received character to it It will remain in this mode until its serial input buffer becomes empty and no serial characters are received for 300 ms at which time it will re address the GPIB device to talk Time termination mode should be used for applications in which bidirectional communication is required and neither a lt CR gt or lt LF gt character is used to signal the end of a command string to the GPIB device lt CR gt or lt LF gt Termination Mode If a command string to the GPIB instrument can be terminated with either a lt CR gt or lt LF gt character you can use either lt CR gt or lt LF gt termination mode to address the GPIB device to send data In these modes when the GPIB 232CV receives the terminating character it will address the GPIB device to talk so that any GPIB data can be input by the GPIB 232CV Any serial character received by the GPIB 232CV at this point will signal the GPIB 232CV to re address the GPIB device as a Listener For example let s say you wish to connect an HP7475 GPIB plotter to an IBM PC serial port via the GPIB 232CV and you want to draw a line get plotter status and then draw a circle In BASIC this could
31. inimum configuration cable are shown in Figure B 2 The GPIB 232CV connector is on the left Assumes that the DCE s handshaking is satisfied internally Figure B 2 Minimum DTE to DCE Cable Configuration If your application requires a custom cable review your serial device s RS 232 characteristics and build the cable to perform the desired functions GPIB 232CV User Manual B 4 National Instruments Corp Appendix B Interfacing to a Serial Device Interfacing the GPIB 232CV to a DTE 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 must fool the GPIB 232CV into thinking it is communicating with a DCE Figure B 3 shows a typical null modem cable Figure B 3 Null Modem Cable Configuration If your serial device does not use the same hardware handshaking protocol as the GPIB 232CV you can either use a minimum configuration null modem cable and use XON XOFF handshaking or you can use a custom cable that will satisfy the GPIB 232CV hardware handshaking protocol The connections for a minimum configuration null modem cable are shown in Figure B 4 National Instruments Corp B 5 GPIB 232CV User Manual Interfacing to a Serial Device Appendix B In Figure B 4 the GPIB 232CV connector is on the left Assumes the serial device s handshake is satisfied internally Figure B 4 Minimum Null Modem Cable Configuration If a custom cable is required
32. ipment and procedures that are appropriate in the particular situation to prevent serious injury or death should always continue to be used when National Instruments products are being used National Instruments products are NOT intended to be a substitute for any form of established process procedure or equipment used to monitor or safeguard human health and safety in medical or clinical treatment FCC DOC Radio Frequency Interference Compliance This equipment generates and uses radio frequency energy and if not installed and used in strict accordance with the instructions in this manual may cause interference to radio and television reception This equipment has been tested and found to comply with the following two regulatory agencies Federal Communications Commission This device complies with Part 15 of the Federal Communications Commission FCC Rules for a Class A digital device Operation is subject to the following two conditions 1 This device may not cause harmful interference in commercial environments 2 This device must accept any interference received including interference that may cause undesired operation Canadian Department of Communications This device complies with the limits for radio noise emissions from digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communications DOC Le pr sent appareil num rique n met pas de bruits radio lectriques d passant
33. les limites applicables aux appareils num riques de classe A prescrites dans le r glement sur le brouillage radio lectrique dict par le minist re des communications du Canada Instructions to Users These regulations are designed to provide reasonable protection against harmful interference from the equipment to radio reception in commercial areas 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 There is no guarantee that interference will not occur in a particular installation However the chances of interference are much less if the equipment is installed and used according to this instruction manual If the equipment does cause interference to radio or television reception which can be determined by turning the equipment on and off one or more of the following suggestions may reduce or eliminate the problem e Operate the equipment and the receiver on different branches of your AC electrical system e Move the equipment away from the receiver with which it is interfering e Reorient or relocate the receiver s antenna e Be sure that the equipment is plugged into a grounded outlet and that the grounding has not been defeated with a cheater plug Notice to user Changes or modifications not expressly approved by National Instruments could void the user s authority to operate the equipment und
34. mary Address 19 GPIB Primary Address 20 GPIB Primary Address 21 GPIB Primary Address 22 GPIB 232CV User Manual 2 6 National Instruments Corp Chapter 2 Configuration and Installation Table 2 3 Configuration Parameters for U22 Switches 4 through 8 continued Switches Indication 6 7 8 GPIB Primary Address 23 GPIB Primary Address 24 GPIB Primary Address 25 GPIB Primary Address 26 GPIB Primary Address 27 GPIB Primary Address 28 GPIB Primary Address 29 GPIB Primary Address 30 Sets listen only operation D mode or no addressing performed C mode National Instruments Corp 2 7 GPIB 232CV User Manual Configuration and Installation Chapter 2 The DIP switch at location U20 on the printed wire board is used to configure the serial port parameters of the GPIB 232CV The DIP switch shown in Figure 2 4 has eight configuration switches Pere RUE Figure 2 4 Factory Default Settings for Switch U20 On DIP switch U20 switch 1 is OFF indicating that XON XOFF is disabled Switch 2 is OFF indicating that the GPIB 232CV will be using 7 bits character for its serial data transfers Switch 3 is OFF which indicates 1 stop bit per character Switches 4 and 5 are both OFF which indicates that parity is disabled Switches 6 through 8 are in the ON OFF ON positions respectively indicating that the serial port will be operating at 9600 baud Tables 2 4 and 2 5 show the possible configurations of the eight
35. n power up will assert Interface Clear IFC and address the GPIB instrument using the GPIB primary address set on the configuration switches An example of a system operating in C mode is a GPIB device such as a digital multimeter connected to an IBM PC serial port through a GPIB 232CV 23934 uy IBM PC GPIB 232CV Digital Multimeter Serial Device GPIB Device Figure 2 1 Example of C Mode System Setup National Instruments Corp 2 1 GPIB 232CV User Manual Configuration and Installation Chapter 2 If your system has a GPIB Controller that is responsible for addressing the GPIB 232CV to talk or listen the GPIB 232CV should be set to operate in the Device D mode It is called the Device mode because the GPIB 232CV functions like another GPIB device An example of a system operating in D mode is a RS 232 device such as a serial printer connected to a GPIB system with an existing GPIB Controller such as an IBM PC with a National Instruments AT GPIB board as shown in Figure 2 2 WHA GPIB Device Serial S Cable NS Printer GPIB 232C Serial Device IBM PC AT GPIB Controller Figure 2 2 Example of D Mode System Setup Installation Install the GPIB 232CV according to the following procedure 1 Inspect the GPIB 232CV for damage that may have been caused in shipment 2 Verify the voltage requirement 3 Configure
36. on on which SRQ will be asserted if enabled is when the GPIB input buffer becomes empty If very large amounts of data are sent over the GPIB to the GPIB 232CV greater than the GPIB buffer size and the serial device is a very slow data acceptor the GPIB 232CV internal GPIB data buffer might become full If this does occur the FULL indicator on the front panel will illuminate and the GPIB transfer rate will slow to approximately the same rate as the serial device accepting the data Since 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 need to transfer data on the bus Serial Poll Responses If the GPIB 232CV is serial polled its response byte will depend upon the status of the internal data buffers If the serial input buffer is empty bit one of the status byte will be set to 1 If the serial input buffer is not empty bit one will be set to 0 If the GPIB input buffer is empty bit zero of the status byte will be set to 1 If the GPIB input buffer is not empty bit one will be set to 0 In all cases bit six will be set to 1 if the GPIB 232CV is requesting service and will be set to 0 otherwise Listen Only Mode The GPIB 232CV will be located at the GPIB address specified by switches 4 through 8 of the configuration DIP switch at location U22 The GPIB 232CV also has the ability to be configured as a listen only device if all GP
37. ore key names enclosed in angle brackets denotes that you should simultaneously press the named keys for example lt Control Alt Delete gt TEEE 488 and TEEE 488 and IEEE 488 2 are used throughout TEEE 488 2 this manual to refer to the ANSI IEEE Standard 488 1 1987 and the ANSL IEEE Standard 488 2 1987 respectively which define the GPIB RS 232 RS 232 is used throughout this manual to refer to the ANSI EIA 232 C standard Abbreviations acronyms metric prefixes mnemonics and terms are listed in the Glossary GPIB 232CV User Manual xii National Instruments Corp About This Manual Related Documentation The following documents contain information that you may find helpful as you read this manual e ANSI EJA 232 Interface Between Data Terminal Equipment and Data Circuit Terminating Equipment Employing Serial Binary Data Interchange e ANSVIEEE Standard 488 1 1987 IEEE Standard Digital Interface for Programmable Instrumentation e ANSI IEEE Standard 488 2 1987 IEEE Standard Codes Formats Protocols and Common Commands Customer Communication National Instruments wants to receive your comments on our products and manuals We are interested in the applications you develop with our products and we want to help if you have problems with them To make it easy for you to contact us this manual contains comment and configuration forms for you to complete These forms are in Appendix D Customer Communication at
38. ough 8 If all address configuration switches are ON no addressing will be performed This is useful if you are talking to a listen only device that does not require addressing The GPIB 232CV will always assert REN when addressing other devices All incoming serial data to the GPIB 232CV is stored in an internal data buffer until it is accepted by the GPIB device All GPIB data sent to the GPIB 232CV is passed immediately to the serial port without being buffered Modes of Operation within C Mode Four different modes of operation within C mode define how the GPIB device is to be addressed time termination lt CR gt termination lt LF gt termination and no swap In all modes the GPIB device is addressed to listen after the GPIB 232CV becomes CIC and all data received via the serial port is buffered The data is then passed along to the GPIB device The four modes of operation define at what point the GPIB device needs to National Instruments Corp 3 5 GPIB 232CV User Manual Operation Chapter 3 be unaddressed to listen and addressed to talk so that data can be sent from the GPIB device to the GPIB 232CV Time Termination Mode In time termination mode the GPIB 232CV will address the GPIB device to talk if the GPIB 232CV serial input buffer becomes empty and no more serial characters are received for 300 ms After this period of inactivity the GPIB 232CV assumes that since no more serial data is being sent the GPIB device m
39. ows you how to connect and use your GPIB 232CV 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 National Instruments Corp C 1 GPIB 232CV User Manual Application Examples Appendix C 1 Use 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 2 Configure the GPIB 232CV to operate in D mode with the small 256 bytes serial port buffer and SRQ disabled The serial buffer 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 assigned to the device plotter or printer in ibconf Configure the serial port parameters to match those of the printer or plotter 3 Connect the GPIB cable from the PC to the GPIB 232CV and connect the serial cable from the GPIB 232CV to the printer or plotter The system should resemble the diagram in Figure C 1 IBM PC A GPIB Controller Printer Serial Device GPIB 232CV Figu
40. peed MHz RAM Display adapter MB Mouse yes no Other adapters installed Hard disk capacity Instruments used MB Brand National Instruments hardware product model Revision Configuration continues National Instruments software product Version Configuration The problem is List any error messages The following steps will reproduce the problem GPIB 232CV Hardware and Software Configuration Form Record the settings and revisions of your hardware and software on the line to the right of each item Update this form each time you revise your software or hardware configuration and use this form as a reference for your current configuration National Instruments Products e GPIB 232CV Model e U20 Switch Setting e U22 Switch Setting Other Products e Operating System and Version e Application Programming Language Other Devices in System e Serial Cable Wiring Diagram Documentation Comment Form National Instruments encourages you to comment on the documentation supplied with our products This information helps us provide quality products to meet your needs Title GPIB 232CV User Manual Edition Date April 1994 Part Number 320109 01 Please comment on the completeness clarity and organization of the manual continues If you find errors in the manual please record the page n
41. re 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 N 488 2 Software Reference Manual for MS DOS which is provided with the National Instruments AT GPIB board 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 GPIB 232CV User Manual C 2 National Instruments Corp Appendix C Application Examples FASTPRINT dumps specified data file out GPIB to device named printer include decl h include lt stdio h gt main argc argv char argv char fname 16 filename int gt prompt for file name if not provided if argc lt 1 printf Enter filename AE gets fname filename fname else filename argv 1 find device printer if f ibfind printer lt 0 fprintf stderr Can t find printer n exit 1 write file if ibwrtf f filename amp 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 no
42. s a reference Signal Ground point for all interface voltages CD 20 DTR This signal line is asserted by the Data Ready GPIB 232CV to signal that it has been powered on and is ready to operate GPIB 232CV User Manual B 2 National Instruments Corp Appendix B Interfacing to a Serial Device To interface other products to the GPIB 232CV serial port consult your manual on that serial device to determine if the device is configured as a DTE or DCE Also notice how the control lines are used and whether they must be driven for the serial port to operate The GPIB 232CV CTS signal is configured so that it must be asserted for the GPIB 232CV to transmit data Interfacing the GPIB 232CV to a DCE A correctly configured DTE to DCE interface is wired straight across GPIB 232CV pin 2 to DCE pin 2 pin 3 to pin 3 and so forth Wired in this manner the GPIB 232CV can then interact to function properly on buffer full conditions handshake Figure B 1 shows a properly configured DTE to DCE cable Figure B 1 DTE to DCE Cable Configuration National Instruments Corp B 3 GPIB 232CV User Manual Interfacing to a Serial Device Appendix B If your serial device does not use the same hardware handshaking protocol as the GPIB 232CV you can either use a minimum configuration cable and use XON XOFF handshaking if necessary or wire a custom cable that will satisfy the GPIB 232CV hardware handshaking protocol The connections for a m
43. switches and what the configurations indicate GPIB 232CV User Manual 2 8 National Instruments Corp Chapter 2 Configuration and Installation Table 2 4 Configuration Parameters for U20 Switches 1 through 5 XON XOFF protocol disabled XON XOFF protocol enabled 7 bits character 8 bits character 1 stop bit character 2 stop bits character parity generation checking disabled parity generation checking enabled odd parity even parity Table 2 5 Configuration Parameters for U20 Switches 6 through 8 Switches Indication 7 8 300 baud 600 baud 1200 baud 2400 baud 4800 baud 9600 baud 19200 baud 38400 baud National Instruments Corp 2 9 GPIB 232CV User Manual Configuration and Installation Chapter 2 Step 4 Connect the Cables Connect the cables as follows 1 Connect the serial cable to the GPIB 232CV and securely fasten the holding screws Connect the other end of the cable to your serial device Be sure to use only shielded serial cable and follow all RS 232 cabling restrictions 2 Connect the GPIB cable to the GPIB 232CV and tighten the thumb screws on the connector Connect the other end to your GPIB system Be sure to follow all IEEE 488 cabling restrictions and use only double shielded GPIB cable 3 Connect the power jack of the wall mount power supply to the power receptacle on the back panel of the GPIB 232CV then plug the supply into an AC outlet of the correct voltage Step 5
44. t sending an amount of data greater than the buffer size of the GPIB 232CV the data transfer should complete in a few seconds National Instruments Corp C 3 GPIB 232CV User Manual Application Examples Appendix C Using the GPIB 232CV to Connect 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 you can avoid this situation because the GPIB 232CV 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 to convert the serial data from AUTOCAD into GPIB data for the plotter The GPIB 232CV automatically takes care of the GPIB addressing and transparently converts the data from one format to the other To use the GPIB 232CV 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 Set it to operate in C mode with timeout termination Set the GPIB address of the plotter using the GPIB 2
45. the end of this manual National Instruments Corp xiii GPIB 232CV User Manual Chapter 1 Description of the GPIB 232CV This chapter contains a brief overview of the GPIB 232CV lists the contents of your kit and optional equipment and describes the panels of the GPIB 232CV Introduction The GPIB 232CV shown in Figure 1 1 provides a method of connecting a device with a RS 232 port to the GPIB or IEEE 488 bus The GPIB 232CV transparently converts data between the two ports so that control codes or special commands are not required The GPIB 232CV also increases the efficiency of the interface system by isolating the slower device from the faster port with a 256 KB character buffer This buffer is used to offload the host computer during printer and plotter applications READY r r _C Figure 1 1 The GPIB 232CV National Instruments Corp 1 1 GPIB 232CV User Manual Description of the GPIB 232CV Chapter 1 The GPIB 232CV is capable of interfacing either a GPIB Controller or a GPIB device to a computer or instrument with a RS 232 port It can be used to interface a GPIB device to a computer with a RS 232 port or to connect a RS 232 device such as a printer or plotter to a GPIB network Data transfers in either direction are possible at all times What Your Kit Contains Your kit should contain the following components One of the following boxes e GPIB 232CV 256
46. the operating parameters 4 Connect the cables 5 Power on the unit GPIB 232CV User Manual 2 2 National Instruments Corp Chapter 2 Configuration and Installation Step 1 Inspection Before you install the GPIB 232CV inspect the shipping container and its contents for damage If damage appears to have been caused in shipment file a claim with the carrier Retain 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 Step 2 Verify the Voltage Requirement The GPIB 232CV is shipped from the factory with either a 115V or 230V wall mount supply Verify that the voltage on the supply matches the voltage that is supplied in your area Warning Operating the unit at any voltage other than the one specified could damage the unit Step 3 Configure the Operating Parameters The GPIB 232CV is shipped from the factory configured to operate in D mode and is set to GPIB primary address 5 The serial port is configured at 9600 baud 1 stop bit no parity and 7 data bits with XON XOFF protocol disabled If you wish to change any of the GPIB 232CV parameters you must open the unit and set the configuration switches To change the configuration switches follow these steps 1 Disconnect power to the unit and disconnect any cables that may be connected to the unit 2 Unscrew the two screws on the opposite sid
47. umbers and describe the errors Thank you for your help Name Title Company Address Phone Mail to Technical Publications National Instruments Corporation 6504 Bridge Point Parkway MS 53 02 Austin TX 78730 5039 Fax to Technical Publications National Instruments Corporation MS 53 02 512 794 5678 Glossary 106 10 3 103 106 2 degree percent A amperes C Celsius hex hexadecimal Hz hertz in inches KB kilobytes of memory m meters MB megabytes of memory OZ ounce sec seconds V volts VAC volts alternating current VDC volts direct current National Instruments Corp G 1 GPIB 232CV User Manual
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