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© National Instruments Corp.

B-1

GPIB-232CV User Manual

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 (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-232 standard, contact

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.

Summary of Contents for GPIB-422CV

Page 1: ...GPIB 422CV...

Page 2: ...Copyright 1987 1994 National Instruments Corporation All Rights Reserved GPIB 232CV User Manual IEEE 488 RS 232 Converter April 1994 Edition Part Number 320109 01...

Page 3: ...stralia 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 I...

Page 4: ...iable 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 SPECIFICA...

Page 5: ...ility 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...

Page 6: ...luding 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...

Page 7: ...y from the receiver with which it is interfering Reorient or relocate the receiver s antenna Be sure that the equipment is plugged into a grounded outlet and that the grounding has not been defeated w...

Page 8: ...1 6 The GPIB Connector 1 7 Chapter 2 Configuration and Installation 2 1 Choosing Between D Mode or C Mode 2 1 Installation 2 2 Step 1 Inspection 2 3 Step 2 Verify the Voltage Requirement 2 3 Step 3 C...

Page 9: ...Handshake 3 8 XON XOFF 3 9 Appendix A Hardware Specifications A 1 Appendix B Interfacing to a Serial Device B 1 The RS 232C Standard B 1 The RS 232C Serial Port B 1 Interfacing the GPIB 232CV to a DC...

Page 10: ...ration B 3 Figure B 2 Minimum DTE to DCE Cable Configuration B 4 Figure B 3 Null Modem Cable Configuration B 5 Figure B 4 Minimum Null Modem Cable Configuration B 6 Figure C 1 Example of Print Spooler...

Page 11: ...s 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 Appendi...

Page 12: ...nd names of variables bold Bold text in this manual denotes a signal name or a front panel LED indicator Angle brackets enclose the ASCII character symbols for certain keystrokes For example CR for ca...

Page 13: ...tandard Digital Interface for Programmable Instrumentation ANSI IEEE Standard 488 2 1987 IEEE Standard Codes Formats Protocols and Common Commands Customer Communication National Instruments wants to...

Page 14: ...gure 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 comma...

Page 15: ...ed 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...

Page 16: ...74 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...

Page 17: ...hat 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...

Page 18: ...ational Instruments Corp 1 5 GPIB 232CV User Manual 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 2...

Page 19: ...ck 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...

Page 20: ...signals supported is shown in Figure 1 5 a suffix indicates that the signal is active low DIO1 DIO2 DIO3 DIO4 EOI DAV NRFD NDAC IFC SRQ ATN SHIELD DIO5 DIO6 DIO7 DIO8 REN GND Twisted Pair with DAV GND...

Page 21: ...PIB 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 t...

Page 22: ...ial 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 IBM PC AT GPIB Controller GPIB Device Serial...

Page 23: ...cified 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 i...

Page 24: ...re 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 1 2 3 4 5 6 7 8 O O F F N U22 Figure 2 3 Factory Default Set...

Page 25: ...cation OFF GPIB 232CV operates in D mode ON GPIB 232CV operates in C mode Table 2 2 Configuration Parameters for U22 Switches 2 and 3 Switches Indication 2 3 D Mode C Mode OFF OFF Small serial buffer...

Page 26: ...ddress 6 OFF OFF ON ON ON GPIB Primary Address 7 OFF ON OFF OFF OFF GPIB Primary Address 8 OFF ON OFF OFF ON GPIB Primary Address 9 OFF ON OFF ON OFF GPIB Primary Address 10 OFF ON OFF ON ON GPIB Prim...

Page 27: ...F ON ON ON GPIB Primary Address 23 ON ON OFF OFF OFF GPIB Primary Address 24 ON ON OFF OFF ON GPIB Primary Address 25 ON ON OFF ON OFF GPIB Primary Address 26 ON ON OFF ON ON GPIB Primary Address 27 O...

Page 28: ...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 i...

Page 29: ...bits character ON 8 bits character 3 OFF 1 stop bit character ON 2 stop bits character 4 OFF parity generation checking disabled ON parity generation checking enabled 5 OFF odd parity ON even parity...

Page 30: ...our 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...

Page 31: ...ll address the instrument to talk and pass all received data to the RS 232 port If using the GPIB 232CV in D mode simply address the GPIB 232CV to listen if not in listen only mode when you have data...

Page 32: ...ator 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 s...

Page 33: ...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...

Page 34: ...er 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 GP...

Page 35: ...ow 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 becom...

Page 36: ...on The action of asserting IFC for at least 100 s 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 o...

Page 37: ...ut 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 bidirec...

Page 38: ...up for CR 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...

Page 39: ...cols 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...

Page 40: ...hanging logic levels on dedicated control lines When you enable the XON XOFF protocol the GPIB 232CV sends the XOFF character decimal 19 or CTRL s when its internal buffer becomes full Once the GPIB 2...

Page 41: ...racteristics Characteristic Specification Power Supply Unit Wall mount type 115 VAC or 230 VAC 50 60 Hz input 9 VDC 1A max output Voltage 9 VDC regulated Current 640 mA typical 750 mA max Table A 2 En...

Page 42: ...l Instruments Corp Table A 3 Physical Characteristics Characteristic Specification Case Size 1 6 in by 5 7 in by 8 4 in 40 6 mm by 144 8 mm by 213 4 mm Case Material All metal enclosure Rack Mounting...

Page 43: ...onal 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 arr...

Page 44: ...e GPIB 232CV CA 4 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 i...

Page 45: ...he 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...

Page 46: ...or wire a custom cable that will satisfy the GPIB 232CV hardware handshaking protocol The connections for a minimum configuration cable are shown in Figure B 2 The GPIB 232CV connector is on the left...

Page 47: ...is communicating with a DCE Figure B 3 shows a typical null modem cable 1 2 3 7 5 4 1 2 3 7 5 4 Figure B 3 Null Modem Cable Configuration If your serial device does not use the same hardware handshaki...

Page 48: ...232CV connector is on the left Assumes the serial device s handshake is satisfied internally 1 2 3 5 20 7 1 2 3 7 Figure B 4 Minimum Null Modem Cable Configuration If a custom cable is required for yo...

Page 49: ...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 232C...

Page 50: ...nnect the serial cable from the GPIB 232CV to the printer or plotter The system should resemble the diagram in Figure C 1 Serial Cable GPIB Cable GPIB 232CV GPIB 422CV IEEE 488 RS 422 CONVERTER POWER...

Page 51: ...rgc 1 printf Enter filename gets fname 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 fpri...

Page 52: ...he 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 re...

Page 53: ...hrough Friday from 8 00 a m to 6 00 p m central time In other countries contact the nearest branch office You may fax questions to us at any time Corporate Headquarters 512 795 8248 Technical Support...

Page 54: ...s 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 manua...

Page 55: ...National Instruments software product Version Configuration The problem is List any error messages The following steps will reproduce the problem...

Page 56: ......

Page 57: ...pdate 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 GPIB 232CV Model U20 Switch S...

Page 58: ...n 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 c...

Page 59: ...e 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 Tec...

Page 60: ...Meaning Value micro 10 6 m milli 10 3 k kilo 103 M mega 106 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 s...

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