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GPIB-232CT User Manual

1. C 4 Null Modem Cable Configuration eee eects C 5 Minimum Null Modem Cable Configuration C 6 GPIB Cable Connector ee eeccesseeseeseeeeeesetseeeaes D 4 Linear Configuration of the GPIB Devices D 7 Star Configuration of GPIB Devices D 8 S mode 7 data bits 1 stop bit even parity 300 baud G 1 S mode 8 data bits 1 stop bit even parity 19200 baud G 2 S mode 8 data bits 1 stop bit no parity 9600 baud G 3 S mode 7 data bits 1 stop bit even parity 300 baud G 3 S mode 8 data bits 1 stop bit even parity 9600 baud G 4 S mode 8 data bits 1 stop bit no parity 19200 baud H 2 S mode 7 data bits 1 stop bit no parity 9600 baud H 5 S mode 8 data bits 1 stop bit no parity 9600 baud H 8 G mode parimary GPIB address 2 0 0 0 eeeeeseseteeneeee H 11 G mode primary GPIB address 18 0 eres H 14 xvii GPIB 232CT User Manual Contents Tables Table 1 1 Electrical Characteristics c0cc ccccccsssssccccessssssssecceesseseees 1 4 Table 1 2 Environmental Characteristics 00 ccccccccsssssssssccsseesssees 1 4 Table 1 3 Physical Characteristics cccessseseeseeneeseceecseeeeseeeees 1 5 Table 1 4 LED DeSCriptiOns vs 25 css secs eenssesteesovctesssavecipeecuesteessaeices 1 6 Table 3 1 Configuration Parameters for Switches 1 through 5 3 3 Table 3 2 Configuration Parameters for Switches 6 through 8 3 4 Table 4 1 Serial Port
2. DIOS DIO6 DIO7 DIO8 REN 18__ GND TW PAIR W DAV GND TW PAIR W NRED GND TW PAIR W NDAC GND TW PAIR W IFC GND TW PAIR W SRQ GND TW PAIR W ATN SIGNAL GROUND Figure D 1 GPIB Cable Connector Data Lines The eight data lines DIO1 through DIO08 carry both data and command messages All commands and most data use the 7 bit ASCII or ISO code set in which case the eighth bit DIO8 is unused or used for parity Appendix A lists the GPIB command messages GPIB 232CT User Manual D 4 National Instruments Corp Appendix D Operation of the GPIB Handshake Lines Three lines asynchronously control the transfer of message bytes among devices The process is called a three wire interlocked handshake and it guarantees that message bytes on the data lines are sent and received without transmission error NRFD not ready for data NRFD indicates when a device is ready or not ready to receive a message byte The line is driven by all devices when receiving commands and by Listeners when receiving data messages NDAC not data accepted NDAC indicates when a device has or has not accepted a message byte The line is driven by all devices when receiving commands and by Listeners when receiving data messages DAV data valid DAV tells when the signals on the data lines are stable valid and can be accepted safely by devices The Controller drives DAV when sending commands and the Tal
3. identification CALL IBWRT GPIB232 WRTS response GPIB 232CT Rev A 0 lt CR gt lt LF gt c 1988 National Instruments lt CR gt lt LF gt 64K bytes RAM lt CR gt lt LF gt National Instruments Corp 8 7 GPIB 232CT User Manual G Mode Functions Chapter 8 onl Place the GPIB 232CT Online Offline Type Syntax Purpose Remarks See Also Examples General Use function onl bool lt CR gt You use on1 to disable communication between the GPIB 232CT and the serial port or to re initialize the GPIB 232CT characteristics to their default values If the argument bool is 1 the GPIB 232CT places itself online If the argument bool is 0 the GPIB 232CT places itself offline By default the GPIB 232CT powers up online If you call on1 without an argument the GPIB 232CT returns the current status of the GPIB 232CT which is 0 if the GPIB 232CT is offline and 1 if the GPIB 232CT is online Placing the GPIB 232CT offline can be thought of as disconnecting its serial cable from the serial device When placed offline no data is sent out the GPIB 232CT serial port and data coming in to the GPIB 232CT serial port is not saved until on1 is called with bool 1 Placing the GPIB 232CT online enables data to be sent and received over its serial port Placing the GPIB 232CT online also restores all GPIB 232CT settings to their power on values Tables 7 1 and 7 2 for the GPIB 232CT power on settings 1 WRTS
4. CHRS 34 response 3 PRINT 1 response Ti ai 92 Define a word called init to initialize an IBM 7320 Color Plotter ok lt CR gt lt LF gt ia fw Executed the word defined in Example 2 ok lt CR gt lt LF gt National Instruments Corp 5 19 GPIB 232CT User Manual S Mode Functions Chapter 5 4 PRINT 1 bye Exit ibcl and return to the NI610 operating system response END CMPL REM CIC LACS NGER NSER 165 Assuming you had continuous status reporting enabled when you called ibcl GPIB 232CT User Manual 5 20 National Instruments Corp Chapter 5 S Mode Functions id Identify System Type General Use function Syntax id lt CR gt Purpose You use id if you wish to know the revision level of your software or if you wish to know how much RAM is installed in your GPIB 232CT Remarks The identification is returned in three strings The first two strings identify the company product model the software revision level and a copyright notice The third string identifies the number of bytes of RAM in the GPIB 232CT Example 1 PRINT 1 id Get system identification response GPIB 232CT Rev A 0 lt CR gt lt LF gt c 1988 National Instruments lt CR gt lt LF gt 64K bytes RAM lt CR gt lt LF gt National Instruments Corp 5 21 GPIB 232CT User Manual S Mode Functions Chapter 5 ist Set or Clear Individual Status Bit ist Parallel Poll fun
5. onl on off spign on off Ignore serial port errors spset modes Change serial port parameters srqen mask Set conditions for asserting SRQ stat options Return GPIB 232CT status xon modes Change serial port XON XOFF protocol Operation of the GPIB 232CT with a Serial Device The serial device attached to the GPIB 232CT looks like any other GPIB device and as such is configured to respond in certain ways to GPIB commands GPIB 610 User Manual 7 10 National Instruments Corp Chapter 7 Programming in G Mode Serial Poll The GPIB 232CT will respond to a serial poll of the serial device by placing a serial poll response byte on the data lines Table 7 7 contains the meanings of the bits in the serial poll response byte Table 7 7 Serial Poll Response Byte B Mnemonic Meaning it 0 1 BF Serial port receive buffer is full 2 GERR GPIB error EARG ECAP ECMD 3 SERR Serial error EPAR EORN EFRM 4 BNE Serial port receive buffer not empty and serial device not addressed to talk 5 EOS EOS character received and GPIB 232CT not addressed to talk RSV 7 Not Used Service Request The GPIB 232CT can be programmed to assert Service Request SRQ ina variety of cases After power on the GPIB 232CT defaults to never asserting service request You can program the GPIB 232CT to assert SRQ under the following circumstances e When the GPIB 232CT serial port receive buffer is full e Whe
6. Configures the GPIB 232CT to operate in S mode Configures the GPIB 232CT to operate in G mode 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 National Instruments Corp 3 3 GPIB 232CT User Manual Installation and Configuration in S Mode Chapter 3 Table 3 2 Configuration Parameters for Switches 6 through 8 Switches Indication 300 baud 600 baud 1200 baud 2400 baud 4800 baud 9600 baud 19200 baud 38400 baud Default Settings for Configuration Switch Figure 3 2 shows the GPIB 232CT s factory default setting for switch U22 Switch 1 is OFF this indicates that the GPIB 232CT will be operating in S mode Switch 2 is OFF this indicates that the GPIB 232CT will be using 7 bits character for its serial data transfers Switch 3 is OFF this indicates 1 stop bit per character Switches 4 and 5 are both OFF this 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 TEC Figure 3 2 Factory Default Settings for Switch U22 GPIB 232CT User Manual 3 4 National Instruments Corp Chapter 3 Installation and Configuration in S Mode Note Switch U20 is not used by S or G mode but can be used for user applications in IBCL mode Step 4 Connect
7. S Mode Functions Chapter 5 caddr Type Syntax Purpose Remarks Change the GPIB Address of the GPIB 232CT Initialization function caddr addr lt CR gt You use caddr at the beginning of your program to change the GPIB address of the GPIB 232CT The argument addr is a device address that specifies the new GPIB address for the GPIB 232CT addr consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Both addresses are expressed as numeric strings Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary address Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 32 98 or 0 x62 If you specify a primary address without a secondary address secondary addressing is disabled If you call caddr without an argument the GPIB 232CT returns to you its current GPIB address The address assigned by this function remains in effect until you call caddr again call on1 or you turn off the GPIB 232CT The power on default is 0 with secondary addressing disabled GPIB 232CT User Manual 5 4 National Instru
8. control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted GPIB 232CT User Manual 5 32 National Instruments Corp Chapter 5 S Mode Functions If the GPIB 232CT is not CIC and you do not specify the Talker address the GPIB 232CT assumes it will be addressed by the Controller then proceeds If you call rd without an argument the GPIB 232CT records the EARG error See Also eos eot and tmo Example 1 PRINT 1 rd 10 3 Read up to 10 bytes from the GPIB device at address 3 RESPS INPUTS 10 1 Input 10 bytes from serial port buffer INPUT 1 COUNTS Input ASCII string representing number of bytes read from the GPIB COUNT is number of bytes read from GPIB remaining bytes in RESPS can be ignored National Instruments Corp 5 33 GPIB 232CT User Manual S Mode Functions Chapter 5 rpp Request Conduct a Parallel Poll Type Syntax Purpose Remarks See Also Parallel Poll function rpp lt CR gt You use rpp if you wish to conduct a parallel poll to obtain information from several devices at the same time rpp causes the GPIB 232CT to conduct a parallel poll of previously configured devices by sending the IDY message ATN and EOI both asserted and reading the response from the GPIB data lines The GPIB 232CT pulses the IDY message for greater than or equal to 2 microseconds a
9. device For example you use gts if you wish to let two external devices to talk to each other directly The GPIB 232CT can selectively participate in the handshake of the data transfer and hold off the handshake when it detects the END message The GPIB 232CT can then take control synchronously without possibly corrupting the transfer Remarks Ifthe argument bool is 1 shadow handshaking is enabled If the argument boo is 0 shadow handshaking is not performed If you call gts without an argument the GPIB 232CT returns to you the current Controller status CSB 0 if the GPIB 232CT is in Standby without shadow handshaking CSB 1 if the GPIB 232CT is in Standby with shadow handshaking CAC if the GPIB 232CT is CIC but is not in Standby that is it is the Active Controller and CIDLE if the GPIB 232CT is not the CIC that is is an IDLE Controller gts causes the GPIB 232CT to go to the Controller Standby state and to unassert the ATN signal if it is initially the Active Controller gts permits GPIB devices to transfer data without the GPIB 232CT participating in the transfer If you enable shadow handshaking the GPIB 232CT participates in the data handshake as an Acceptor without actually reading the data It monitors the transfers for the END EOI or end of string character message and holds off subsequent transfers This mechanism allows the GPIB 232CT to take control synchronously on a subsequent operation such as cmd or rpp
10. you can change the other default GPIB read and write termination methods National Instruments Corp 4 5 GPIB 232CT User Manual Programming in S Mode Chapter 4 S Mode Default Settings Tables 4 1 and 4 2 list power on characteristics of the GPIB 232CT and the functions you can use to change those characteristics Table 4 1 Serial Port Characteristics Characteristic Function Table 4 2 GPIB Characteristics Power on Characteristic Value Function Primary secondary address pad 0 sad none caddr End of string modes none eo S i y es fe is GPIB 232CT User Manual 4 6 National Instruments Corp Chapter 4 Programming in S Mode List of S Mode Functions by Group The GPIB 232CT functions are divided into three main groups GPIB functions Serial Port functions and General Use functions GPIB Functions The GPIB functions are divided into subgroups as shown in the following tables The subgroups are listed with the most frequently used groups first Often the I O and bus management functions are the only ones you need Table 4 3 I O Functions Function Purpose RD count address Read data WRT count address list data Write data Table 4 4 Bus Management Functions Function Purpose CLR address list Clear specified device s LOC address list Go to Local TRG address list Trigger selected device s National Instruments Corp 4 7 GPIB 232CT User M
11. 13 CALL IBWRT GPIB232 WRTS 2 REM What are the current GPIB 232 serial port REM settings WRTS SPSET CHRS 13 CALL IBWRT GPIB232 WRTS REM RESPS will contain 19200 E 7 2 lt CR gt lt LF gt REM 19200 baud even parity 7 data bits REM 2 stop bits CALL IBRD GPIB232 RESPS 3 REM Set the GPIB 232CT serial port to 1200 baud REM no parity 8 data bits and 1 stop bit WRTS spset 1200 n 8 1 CHRS 13 CALL IBWRT GPIB232 WRTS National Instruments Corp 8 11 GPIB 232CT User Manual G Mode Functions Chapter 8 srgen Enable Disable Setting of SRQ Type GPIB Configuration function Syntax srqen mask lt CR gt Purpose You use srqen when you wish to allow the GPIB 232CT to assert SRQ under the conditions described in Chapter 7 in the section entitled Operation of the GPIB 232CT as a Serial Device Remarks When the argument mask is 0 the GPIB 232CT will never assert SRQ When the argument mask is gt 0 the GPIB 232CT will assert SRQ under the conditions represented by each bit in the mask The mask bits are as follows Table 8 2 SRQ Mask Bits Decimal Value Description B it serial device not addressed to talk 8 8 10 16 3 SERR Serial error see stat F 4 BNE Serial port receive buffer not empty and serial device not addressed to talk 5 20 32 EOS EOS character received and serial device not addressed to talk 6 40 64 Not used 7 80 128 Not used GPI
12. 232CT you can achieve bi directional flow control by using a serial cable that connects the GPIB 232CT s RTS signal to the serial device s CTS signal In addition the serial device s RTS signal should be connected to the GPIB 232CT s CTS signal This setup allows each device to monitor the other device s RTS signal and to suspend transmission when necessary to prevent data loss Note CTS must be asserted for the GPIB 232CT to transmit data If you do not use hardware handshaking you can usually make CTS asserted by tying together the CTS and DTR serial signals of the GPIB 232CT National Instruments Corp C 7 GPIB 232CT User Manual The Serial Connection Appendix C XON XOFF If your RS 232 serial device does not recognize the hardware handshake scheme you can enable the XON XOFF handshaking protocol This handshaking protocol performs the same function as the hardware handshake but does it 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 232CT sends the XOFF character decimal 19 or lt CTRL gt s when its internal buffer becomes full Once the GPIB 232CT is able to start receiving characters again it sends the XON character decimal 17 or lt CTRL gt q When you enable the GPIB 232CT to recognize XON XOFF if the GPIB 232CT is transmitting data and receives XOFF it suspends transmission of any further data until it
13. 232CT User Manual S Mode Functions Chapter 5 sre Set or clear Remote Enable Type Syntax Purpose Remarks See Also Examples 1 PRINT Specialized Controller function sre bool lt CR gt You use sre if the I O and bus management functions do not meet the needs of your device sre gives you more precise control over the GPIB Use sre to turn the Remote Enable signal on and off sre is not a function you will use frequently because in most cases the first I O or bus management function you call will set remote enable automatically If the argument boo is 1 the GPIB 232CT asserts the Remote Enable REN signal If the argument boo is 0 the GPIB 232CT unasserts REN Many GPIB devices have a remote program mode and a local program mode It is usually necessary to place devices in remote mode before programming them from the GPIB A device enters the remote mode when the REN line is asserted and the device receives its listen address Use cmd to send a device its listen address after using sre Use loc to return the device to local program mode If you call sre with an argument and the GPIB 232CT is not System Controller the GPIB 232CT records the ESAC error If you call sre without an argument the GPIB 232CT returns its current remote status 1 remote 0 local rsc cmd and loc 2 PRINT 1 SRE 1 Set REN 1 sre 0 Unassert REN GPIB 232CT User Manual 5 46 National Instru
14. Digital Interface for Programmable Instrumentation National Instruemnts Corp A 1 GPIB 232CT User Manual Multiline Interface Messages Appendix A Multiline Interface Messages Hex Oct Dec ASCH Msg Hex Oct Dec ASCII Msg 00 000 0 NUL 20 040 32 SP MLAO 01 001 1 SOH GTL 21 041 33 MLA1 02 002 2 STX 22 042 34 i MLA2 03 003 3 ETX 23 043 35 MLA3 04 004 4 EOT SDC 24 044 36 MLA4 05 005 5 ENQ PPC 25 045 37 MLAS 06 006 6 ACK 26 046 38 amp MLA6 07 007 7 BEL 27 047 39 i MLA7 08 010 8 BS GET 28 050 40 MLA8 09 011 9 HT TCT 29 051 41 MLA9 0A 012 10 LF 2A 052 42 MLA10 OB 013 11 VT 2B 053 43 MLA11 oc 014 12 FF 2C 054 44 MLA12 OD 015 13 CR 2D 055 45 MLA13 OE 016 14 SO 2E 056 46 MLAI4 OF 017 15 SI 2F 057 47 MLAI5 10 020 16 DLE 30 060 48 0 MLA16 11 021 17 DCI LLO 31 061 49 1 MLAI7 12 022 18 DC2 32 062 50 2 MLAI8 13 023 19 DC3 33 063 51 3 MLA19 14 024 20 DC4 DCL 34 064 52 4 MLA20 15 025 21 NAK PPU 35 065 53 5 MLA21 16 026 22 SYN 36 066 54 6 MLA22 17 027 23 ETB 37 067 55 7 MLA23 18 030 24 CAN SPE 38 070 56 8 MLA24 19 031 25 EM SPD 39 071 57 9 MLA25 1A 032 26 SUB 3A 072 58 MLA26 1B 033 27 ESC 3B 0733 59 MLA27 1C 034 28 FS 3C 074 60 lt MLA28 ID 035 29 GS 3D 075 6l MLA29 1E 036 30 RS 3E 076 62 gt MLA30 1F 037 31 US 3F 077 63 UNL Message Definitions DCL Device Clear MSA My Secondary Address GET Group Execute Trigger MTA My Talk Address GTL Go To Local PPC Parallel Poll Configure LLO Local Lockout PPD Parallel
15. GPIB 232CT provides when serially polled by another device that is CIC If bit 6 hex 40 RQS bit is also set the GPIB 232CT additionally requests service by asserting the SRQ line If you call rsv without an argument the GPIB 232CT returns a numeric string containing the decimal value of its serial poll status byte 1 PRINT 1 rsv x46 Request service with serial po response 6 2 PRINT 1 rsv What is the current serial po status byte response 70 lt CR gt lt LF gt The current status byte decimal 70 or hex 46 National Instruments Corp 5 41 GPIB 232CT User Manual S Mode Functions Chapter 5 sic Send Interface Clear Type Syntax Purpose Remarks Specialized Controller function sic time lt CR gt You use sic if the initialization I O or bus management functions do not meet the needs of your device and you wish to have more precise control over the GPIB sic makes the GPIB 232CT CIC and initializes the GPIB sic is nota function you will use frequently because in most cases the first I O or bus management function you call will do this automatically The argument time is a numeric string specifying any number of seconds between 0001 and 3600 which corresponds to time limits between 100 microseconds and 1 hour time must not contain a comma If you call sic without an argument IFC is sent for 500 microseconds The action of asserting IFC for at least 1
16. GPIB Initialization Functions Determine what GPIB initialization functions are needed to change default settings If you are not sure what GPIB settings you might want to change try using the defaults No changes were necessary for this GPIB plotter Step 4 Communicate with rd and wrt Functions Use rd and wrt to communicate with the device In this example we want to send plotter commands to the GPIB plotter so we only need the wrt programming message The plotter s address is 5 In the following example the programming messages and data strings that you enter are shown in regular type Responses sent to you by the GPIB 232CT are shown in boldface type By looking at the status information returned after each programming message you can see if any GPIB or serial port errors occurred and you can see the number of bytes actually transferred out on the GPIB The command tmo 30 on the second line of the following example lengthens the timeout from 10 seconds default to 30 seconds to allow you more time to type the data string for the wrt commands echo 1 lt CR gt tmo 30 lt CR gt stat c s lt CR gt CMPL NGER NSER 0 wrt 5 lt CR gt IN SP1 1P2650 1325 7650 6325 lt CR gt CMPL CIC TACS NGER NSER 29 wrt lt CR gt Sc 100 100 100 100 PAO 0 CI40 lt CR gt CMPL CIC TACS NGER NSER 31 GPIB 232CT User Manual H 4 National Instruments Corp Appendix H Sample Programs Using an HP 7475A Plotter wi
17. IBFIND SDNAMES PLOTTERS 45 Open PLOTTER 50 TS Stat c n CHR 13 60 LL IBWRT GPIB232CT WRTS 65 nable continuous status reporting 70 S SPACES 25 80 LL IBRD GPIB232CT RDS Read up to 90 25 bytes of status information 100 IF ASC RDS CHRS 45 THEN GOTO 400 110 If first character in RDS is a minus sign 120 then go to error ftn 130 WRTS spset 7 135 Change the serial port configuration 140 CALL IBWRT GPIB232CT WRTS to 7 data 145 bits plotter configuration 150 CALL IBRD GPIB232CT RDS Read status info 160 IF ASC RDS CHRS 45 THEN GOTO 400 70 If first character in RDS 80 is a minus sign then go to error function 190 WRTS IN SP1 1IP2650 1325 7650 6325 200 Initialize plotter select pin 1 set 210 scaling points 220 WRTS WRTS SC 100 100 100 100 230 Scale the plotting area 240 WRTS WRTS PA50 40 CI30 30 250 Plot absolute circle radius 260 30 degrees chordangle 30 degrees 270 CALL IBWRT PLOTTER WRTS 330 STOP 400 PRINT An error occurred 410 PRINT status GPIB error serial error Q3 POM Yaw Q W National Instruments Corp H 13 GPIB 232CT User Manual Sample Programs Appendix H 415 count RDS 420 END IBM PC with GPIB PC to Serial Printer This example demonstrates how to control a serial printer on the GPIB The printer is the Apple Imagew
18. National Instruments Corp 5 17 GPIB 232CT User Manual S Mode Functions Chapter 5 Before performing a gts with a shadow handshake you should call eos to establish the proper end of string character or to disable the EOS detection if the end of string character used by the Talker is not known If you call gts with an argument and the GPIB 232CT is not CIC the GPIB 232CT records the ECIC error See Also cac Examples 1 PRINT 1 gts 0 GTS without shadow handshaking 2 PRINT 1 GTS 1 GTS with shadow handshaking 3 PRINT 1 gts What is standby status response CSB 1 lt CR gt lt LF gt GPIB 232CT is in standby status with shadow handshaking GPIB 232CT User Manual 5 18 National Instruments Corp Chapter 5 S Mode Functions ibcl Enter ibcl Operating System Type General Use function Syntax ibcl lt CR gt Purpose You use ibc1 if you wish to enter the interface bus control language operating system Remarks After entering ibc1 the user has access to most of the same GPIB words commands as in S mode In addition to the GPIB words there are other predefined words that the user could use to write complex programs and custom applications See Also The GPIB CT IBCL Reference Manual included with your package Examples 1 PRINT 1 ibcl Enter the ibcl operating system response lt CR gt lt LF gt ok lt CR gt lt LF gt 2 PRINT 1 init 5 CHRS 34 IN
19. OFF OFF OFF OFF gt OFF OFF OFF OFF ON wW OFF OFF OFF ON OFF Q OFF OFF OFF ON ON J OFF OFF ON OFF OFF les OFF OFF ON OFF ON isl OFF OFF ON ON OFF Q OFF OFF ON ON ON T OFF ON OFF OFF OFF ol OFF ON OFF OFF ON oy OFF ON OFF ON OFF nw OFF ON OFF ON ON m OFF ON ON OFF OFF OFF ON ON OFF ON Z OFF ON ON ON OFF O OFF ON ON ON ON ae ON OFF OFF OFF OFF ON OFF OFF OFF ON continues GPIB 232CT User Manual 6 4 National Instruments Corp Chapter 6 Installation and Configuration in G Mode Table 6 1 Primary Address Configurations continued Listen Talk Switches Primary Address Address Address Dec ASCII Dec ASCII O N OFF OFF ON OFF 18 50 O N OFF OFF ON ON 19 51 O Z OFF ON OFF OFF 20 52 4 O Z OFF ON OFF ON 2 1 53 5 85 N OFF ON ON OFF 22 54 6 86 N OFF ON ON ON 23 55 7 87 N ON OFF OFF OFF 24 56 8 88 N ON OFF OFF ON 25 57 9 89 T 26 58 90 N ON OFF ON OFF Z K G Z O O Oloj o o ZI Z Z 24 KIX O Z ON OFF ON ON 27 59 O ON ON OFF OFF 28 60 O Z ON ON OFF ON 29 61 O Z ON ON ON OFF 30 62 National Instruments Corp 6 5 GPIB 232CT User Manual Installation and Configuration in G Mode Chapter 6 Example Settings for Configuration Switch Figure 6 2 shows an example setting of the configuration switch Switches 1 2 and 3 are ON OFF and OFF res
20. Poll Disable MLA My Listen Address GPIB 232CT User Manual A 2 National Instruments Corp Appendix A Multiline Interface Messages Multiline Interface Messages Hex Oct Dec ASCII Msg Hex Oct Dec ASCII Msg 40 100 64 MTAO 60 140 96 MSAO PPE 41 101 65 A MTAI 61 141 97 a MSA1 PPE 42 102 66 B MTA2 62 142 98 b MSA2 PPE 43 103 67 C MTA3 63 143 99 c MSA3 PPE 44 104 68 D MTA4 64 144 100 d MSA4 PPE 45 105 69 E MTA5 65 145 101 MSA5 PPE 46 106 70 F MTA6 66 146 102 f MSA6 PPE 47 107 71 G MTA7 67 147 103 g MSA7 PPE 48 110 72 H MTA8 68 150 104 h MSA8 PPE 49 111 73 I MTA9 69 151 105 i MSA9 PPE 4A 112 74 J MTA10 6A 152 106 j MSA10 PPE 4B 113 75 K MTAI1 6B 153 107 k MSA11 PPE 4C 114 76 L MTAI12 6C 154 108 1 MSA12 PPE 4D 115 7 M MTA13 6D 155 109 m MSA13 PPE 4E 116 78 N MTA14 6E 156 110 n MSA14 PPE 4F 117 79 O MTAI15 6F 157 111 o MSA15 PPE 50 120 80 P MTA16 70 160 112 p MSA16 PPD 51 121 81 Q MTA17 71 161 113 q MSA17 PPD 52 122 82 R MTAI8 72 162 114 r MSA18 PPD 53 123 83 S MTAI19 73 163 115 s MSA19 PPD 54 124 84 T MTA20 74 164 116 t MSA20 PPD 55 125 85 U MTA21 75 165 117 u MSA21 PPD 56 126 86 V MTA22 76 166 118 v MSA22 PPD 57 127 87 W MTA23 77 167 119 w MSA23 PPD 58 130 88 X MTA24 78 170 120 x MSA24 PPD 59 131 89 Y MTA25 79 171 121 y MSA25 PPD 5A 132 90 Z MTA26 7A 172 122 z MSA26 PPD 5B 133 91 I MTA27 7B 173 123 MSA27 PPD 5C 134 92 MTA28 7C 174 124 MSA28 PPD 5D 135 93 MTA29 7D 175 125 MSA29 PPD 5E 136 94 MTA30 7E 176 12
21. Preface The GPIB 232CT User Manual describes the features functions and operation of the Product The GPIB 232CT 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 rackmounted Organization of the GPIB 232CT User Manual The GPIB 232CT User Manual is organized as follows Chapter 1 Description of the GPIB 232CT contains general information about the National Instruments GPIB 232CT the IEEE 488 bus and the RS 232 port This chapter also lists all components and accessories as well as provides electrical environmental and physical specifications Chapter 2 The GPIB 232CT Modes of Operation explains the two modes of operation of the GPIB 232CT Chapter 3 Installation and Configuration in S Mode contains the S mode installation and configuration steps Chapter 4 Programming in S Mode explains how to program the GPIB 232CT when operating in S mode Chapter 5 S Mode Functions gives a detailed description of each S mode function The functions are arranged in alphabetical order and each contains the syntax purpose and examples Chapter 6 Installation and Configuration in G Mode contains the G mode installation and configuration steps Chapter 7 Programming in G Mode explains how to program the GPIB 232CT when operating in G mode Chapter 8 G Mode Functions gives a detailed descript
22. R alone is chosen reads terminate when the low seven bits of the byte that is read match the low seven bits of the EOS character If Methods R and B are chosen a full 8 bit comparison is used Methods X and B together determine when GPIB write operations performed by the GPIB 232CT send the END message If Method X alone is chosen the END message is sent automatically with the EOS byte when the low seven bits of that byte match the low seven bits of the EOS character If Methods X and B are chosen a full 8 bit comparison is used Note Defining an EOS byte for the GPIB 232CT does not cause the GPIB 232CT to insert that byte into the data string when performing GPIB writes To send the EOS byte you must include it in the data string that you send following the wrt programming message By default no eos modes are enabled If you call eos with B alone as an argument the GPIB 232CT records the EARG error If you call eos without an argument the GPIB 232CT returns to you the current eos settings The assignment made by this function remains in effect until you call eos again call on1 or you turn off the GPIB 232CT See Also Chapter 4 the section entitled GPIB Read and Write Termination Method National Instruments Corp 5 13 GPIB 232CT User Manual S Mode Functions Chapter 5 Examples 1 PRINT 1 eos R B 10 Terminate read when lt LF gt is detected compare all 8 bits do not send EOI with lt L
23. SH AH T TE L LE PP C via L LE SH AH DC via L LE DT RL L LE PP T TE L LE C RL L LE RL T TE LE T TE L TE T TE TE LE PP National Instruments Corp Appendix A Multiline Interface Messages Interface Message Reference List continued Mnemonic Message Interface Function s REMOTE MESSAGES RECEIVED continued PPC parallel poll configure PPD parallel poll disable PPE parallel poll enable PPRn parallel poll response n PPU parallel poll unconfigure REN remote enable RFD ready for data RQS request service SDC selected device clear SPD serial poll disable SPE serial poll enable SRQ service request STB status byte TCT or TCT take control UNL unlisten REMOTE MESSAGES SENT ATN attention DAB data byte DAC data accepted DAV data valid DCL device clear END end via T GET group execute trigger GTL go to local IDY identify IFC interface clear LLO local lockout MLA or MLA my listen address MSA or MSA my secondary address MTA or MTA OSA OTA PCG PPC PPD PPE PPRn PPU REN RFD my talk address other secondary address other talk address primary command group parallel poll configure parallel poll disable parallel poll enable parallel poll response n parallel poll unconfigure remote enable ready for data National Instruments Corp A 5 SH via L LE DC T TE T TE via C via L LE C L LE C
24. address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary address Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 The GPIB 232CT reads data from the GPIB until the specified byte count is reached the GPIB END message is received with a data byte the EOS byte is received or a timeout occurs Because you may not know for certain the number of bytes actually read from the GPIB the GPIB 232CT returns the received GPIB data to you in the following manner First the GPIB 232CT returns to you all bytes it read from the GPIB Next it sends null bytes until the total number of bytes returned to you matches your requested count Finally it returns a numeric string representing the number of bytes that it actually read from the GPIB National Instruments Corp 5 31 GPIB 232CT User Manual S Mode Functions Chapter 5 For example if you send the GPIB 232CT the programming message rd 10 lt CR gt it reads data from the GPIB until it receives 10 bytes of data the END message or an eos byte Let s say the GPIB 232CT receives END with the fourth data byte The GP
25. address from the secondary address The listen address is 32 primary address plus 32 the National Instruments Corp 4 3 GPIB 232CT User Manual Programming in S Mode Chapter 4 talk address is 64 primary address plus 64 and the secondary address is 2 or 98 which are equivalent The next paragraph explains the x notation 0 2 or 0 98 or 324 98 or 0 x62 Numeric String Argument Another type of argument is a numeric string A numeric string represents an integer which you can express using decimal octal or hexadecimal digits To specify an octal integer precede it with a backslash To specify a hexadecimal integer precede it with a backslash x x or backslash X X Each of the following numeric strings represents the decimal integer value 112 The GPIB address argument described in the preceding discussion GPIB Address consisted of one or two numeric strings Status Information The function descriptions in Chapter 5 explain that the GPIB 232CT records specific status and error information This means that it stores that information in its memory so that the status information is available to you when you request it The function descriptions also explain that the GPIB 232CT returns to you certain information This means that the GPIB 232CT sends information to you over the serial port You then read this information from your serial port GPIB 232CT User Manual 4 4 National Instruments Corp Chap
26. all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 If you call clr with alist the GPIB 232CT clears only the devices specified in alist Selected Device Clear If you call clr without alist the GPIB 232CT clears all devices Device Clear If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable GPIB 232CT User Manual 5 6 National Instruments Corp Chapter 5 S Mode Functions If you passed control to some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted See Also Appendix D for more information on clearing devices and Appendix B for more error information Examples 1 PRINT 1 clr 144 30 164 12 18 3 26 6 Selectively clear 5 devices 2 PRINT 1 CLR Issue Device Clear to all devices National Instruments Corp 5 7 GPIB 232CT User Manual S Mode Functions Chapter 5 cmd Send GPIB Commands Type Syntax Purpose Remarks Specialized Controller function cmd count lt CR gt commands lt CR gt You use cmd when the I O and bus man
27. at the serial port faster than the serial port can accept them When this error occurs one or more characters sent to the serial port have been lost If this error occurs check to see that the GPIB 232CT and your serial device are using the same serial port settings EOFL 3 The GPIB 232CT records this error when the GPIB 232CT s internal serial port buffer overflows This should only occur if XON XOFF is disabled and there is no hardware handshake in effect GPIB 232CT User Manual B 10 National Instruments Corp Appendix B Status Information EFRM 4 The GPIB 232CT records this error when a character is received whose stop bits are not in the expected place This can happen when the number of bits per character setting of the GPIB 232CT does not match your serial device It can also happen if the baud rates of the GPIB 232CT and your serial device do not match or if one side of the serial link does not use parity and the other side does National Instruments Corp B 11 GPIB 232CT User Manual Appendix C The Serial Connection The serial port on the GPIB 232CT provides an asynchronous serial communication link between the GPIB 232CT and a serial peripheral device The connector for the port is located on the rear panel This appendix is a review of the RS 232 standard at the physical and electrical levels This information will be helpful if you decide to build your own cable If you would like more information on the R
28. change these switch settings be sure to power the GPIB 232CT off and then power it on again Check all of your cable connections National Instruments Corp E 3 GPIB 232CT User Manual Appendix F Parallel Polling A GPIB Controller can use parallel polling to obtain information from several devices on the GPIB in one operation The Controller polls configured devices and reads back a single response byte that contains one bit of information from each device From this information the Controller can determine which devices need servicing Operation A device is configured by sending it its listen address and a parallel poll enable PPE message There are 16 possible PPE messages hex 60 through hex 6F The bits in the PPE message have the following meaning U S DIO lines 1 8 0 1 1 X X X X X When 0 hex 6X parallel poll is enabled When 1 hex 7X parallel poll is disabled When the device s IST individual status bit matches the S bit the device will set the appropriate data line Hex 60 through hex 67 set S to 0 hex 68 through hex 6F set S to 1 The value n in bits 0 2 corresponds to one of the DIO lines 1 through 8 where n corresponds to DIO line n 1 Thus a value of 2 binary 010 corresponds to DIO line 3 The circumstances under which a device sets its IST bit are specific to that device For example a device might always set the IST bit to 1 when it is National Instruments Corp F 1 GPIB 232CT
29. example if you wish to wait until a device requests service before you perform a serial poll In this case you send the wait programming message with mask 4096 then wait for status information to be returned You then check that status to see if the SRQI bit is set in the returned status indicators To prevent the GPIB 232CT from waiting indefinitely for SRQ to be asserted set the SRQI and TIMO bits by setting the mask equal to 4096 16384 This will cause the wait to terminate either on SRQI or TIMO whichever occurs first National Instruments Corp 5 57 GPIB 232CT User Manual S Mode Functions Chapter 5 Table 5 5 Wait Mask Values Decimal Mnemonic Description Value Reserved 16384 TIMO Timeout 4000 8192 END EOI or EOS detected 2000 4096 SRQI SRQ detected while CIC 1000 Reserved Attention asserted TACS Talker active LACS Listener active 2 DTAS Device trigger state 2 1 1 DCAS Device clear state 1 0 If mask 0 the function completes immediately and returns the current status GPIB 232CT User Manual 5 58 National Instruments Corp Chapter 5 S Mode Functions If the TIMO bit is 0 or the timeio time limit is set to 0 with tmo timeouts for this function are disabled You should disable timeouts only when you are certain the selected event will occur otherwise the GPIB 232CT waits indefinitely for the event to occur If you call wait without an argument the GPIB 232CT re
30. get a response string To see if this is the problem ask for status see stat and check to see if the ECIC error occurred If it did you have passed control or System Controller authority to some other GPIB device and will not be able to perform a serial poll until the GPIB 232CT gets Controller authority back GPIB 232CT User Manual E 2 National Instruments Corp Appendix E Common Questions G Mode Question After I write the programming message Stat cs to the GPIB 232CT status is not returned All I get is a carriage return followed by a linefeed lt CR gt lt LF gt Why don t I get status information Answer Every programming message must be followed by a carriage return and or linefeed In BASIC you can build your string as follows stat c s chr 13 Question After I write the programming message Stat c s chr 13 to the GPIB 232CT in G mode my system times out when I try to read status Why Answer Have you addressed the GPIB 232CT to talk To read responses to programming messages you send to the GPIB 232CT you must address the GPIB 232CT to talk using the address you selected on the configuration switch and adding decimal 64 to it Question Whenever I send a programming message to the GPIB 232CT it seems as if the GPIB 232CT never receives it The GPIB 232CT is powered on and its READY LED is on Answer On U22 switch 1 must be on for G mode and switches 2 and 3 must be off If you must
31. it records the ECIC error If you call pct without an argument the GPIB 232CT records the EARG error 1 PRINT 1 pct 7 18 Pass control to device with primary address 7 and secondary address 18 GPIB 232CT User Manual 5 26 National Instruments Corp Chapter 5 S Mode Functions ppc Parallel Poll Configure Type Syntax Purpose Remarks Parallel Poll function ppc addr ppr s addr ppr s lt CR gt You use ppc to configure specified devices to respond to parallel polls in a certain manner addr specifies the GPIB address of the device to be enabled or disabled for parallel polls addr consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Both addresses are expressed as numeric strings Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary addresses Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 The argument ppr is an integer string between 1 and 8 specifying the data line on which to respond The argument s is either 0 or 1 and is interpreted along with
32. it uses a hardware handshake Why would you want to enable the protocol in one case and not the other Some serial devices use XON XOFF protocol when transmitting data but not when receiving In this case you might configure the GPIB 232CT using the second example GPIB 232CT User Manual 8 20 National Instruments Corp Chapter 8 G Mode Functions The power on default is that XON XOFF for both cases is disabled If you call xon without an argument the GPIB 232CT returns to you the current settings 1 protocol enabled 0 protocol disabled Examples 1 WRTS XON 1 1 CHR 13 CALL IBWRT GPIB232 WRTS WRTS XON 0 1 CHR 13 CALL IBWRT GPIB232 WRTS WRTS XON CHRS 13 CALL IBWRT GPIB232 WRTS CALL IBRD GPIB232 RESP National Instruments Corp 8 21 Enable GPIB 232CT XON XOFF protocol for TX and RX Disable protocol on TX enable protocol on RX Return current settings RESPS contains 0 1 lt CR gt lt LF gt transmit protocol disabled receive protocol enabled GPIB 232CT User Manual Appendix A Multiline Interface Messages This section contains an interface message reference list which describes the mnemonics and messages that correspond to the interface functions These multiline interface messages are sent and received with ATN TRUE For more information on these messages refer to the IEEE 488 Std 488 1978 IEEE Standard
33. line is unasserted S G 256 The CMPL bit specifies that the operation relating to this status information is complete This bit is always set and is useful in identifying the status word from other responses S 128 The LOK bit specifies whether the GPIB 232CT is in a lockout state The LOK bit is set whenever the GPIB 232CT detects the Local Lockout LLO message has been sent either by the GPIB 232CT or by another Controller The LOK bit is cleared when the Remote Enable REN GPIB line becomes unasserted either by the GPIB 232CT or by another Controller GPIB 232CT User Manual B 2 National Instruments Corp Appendix B REM CIC ATN TACS Status Information S 64 The REM bit specifies whether the GPIB 232CT is in remote state The REM bit is set whenever the Remote Enable REN GPIB line is asserted and the GPIB 232CT detects its listen address has been sent either by the GPIB 232CT or by another Controller The REM bit is cleared whenever REN becomes unasserted or when the GPIB 232CT as a Listener detects the Go to Local GTL command has been sent either by the GPIB 232CT or by another Controller or when the LOC function is called while the LOK bit is cleared in status S 32 The CIC bit specifies whether the GPIB 232CT is the Controller In Charge The CIC bit is set whenever sic is called while the GPIB 232CT is System Controller or when another Controller passes control to the GPIB 232CT The CIC bit i
34. more than one programming message per GPIB write operation embed a lt CR gt or an lt LF gt in the data string you send For example to send the two programming messages change serial port parameters and change serial port XON XOFF protocol you could either send two separate strings to the GPIB in two separate GPIB writes National Instruments Corp 8 1 GPIB 232CT User Manual G Mode Functions Chapter 8 WRTS SPSET 1200 n 8 CHRS 13 CALL IBWRT GPIB232 WRTS WRT2 S XON 1 1 CHR 13 CALL IBWRT GPIB232 WRTS or you could put both messages in one string and send it to the GPIB 232CT in one GPIB write WRTS SPSET 1200 n 8 CHRS 13 XON 1 1 CHRS 13 CALL IBWRT GPIB232 WRTS e Itis necessary for you to send only enough characters of the function name to distinguish it from other functions These characters are shown in boldface in the syntax portion of the function descriptions GPIB 232CT User Manual 8 2 National Instruments Corp Chapter 8 G Mode Functions echo Echo Characters Received from Serial Port Type Syntax Purpose Remarks Serial Port Configuration function echo bool lt CR gt You use echo when a terminal is connected to the GPIB 232CT and you wish to display what you type on the screen of the terminal If the argument bool is 1 characters received from the serial port are echoed back to the serial port If the argument bool is 0 characters are not echoe
35. onl 1 CHRS 13 Put the GPIB 232CT CALL IBWRT GPIB232 WRTS online and restore its power on settings 2 WRTS ONL 0 CHRS 13 Put the GPIB 232CT CALL IBWRT GPIB232 WRTS offline GPIB 232CT User Manual 8 8 National Instruments Corp Chapter 8 G Mode Functions spign Ignore Serial Port Errors Type Syntax Purpose Remarks Examples Serial Port function spign bool lt CR gt You use spign at the beginning of your program if you wish to change the effect that serial port errors have on the storage of a character received with a serial error This function tells the GPIB 232CT to ignore or not to ignore the occurrence of serial port errors By default the GPIB 232CT ignores serial port errors If the argument bool is 0 the GPIB 232CT will not ignore serial port errors When bool is 0 the GPIB 232CT does not store characters that contain serial errors A list of serial port errors are listed in Appendix B The serial port errors include parity overrun framing and overflow errors If the argument bool is 1 the GPIB 232CT stores all serial port errors occur Also no serial error code will be reported by the stat function 1 WRT Spign 0 CHRS 13 Do not ignore CALL IBWRT GPIB232 WRTS serial port errors 2 WRT Spign 1 CHRS 13 Tgnore serial port CALL IBWRT GPIB232 WRTS errors National Instruments Corp 8 9 GPIB 232CT User Manual
36. power on settings 2 PRINT 1 ONL 0 Put the GPIB 232CT offline to prevent it from communicating with the GPIB National Instruments Corp 5 25 GPIB 232CT User Manual S Mode Functions Chapter 5 pet Pass Control Type Syntax Purpose Remarks Example Specialized Controller function pet addr lt CR gt You use pct to pass Controller In Charge CIC authority from the GPIB 232CT to some other device The argument addr is the address of the device you wish to pass control to addr consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Both addresses are expressed as numeric strings Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary addresses Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 pct passes CIC authority from the GPIB 232CT to the device specified by addr The GPIB 232CT automatically goes to Controller Idle State It is assumed that the target device has Controller capability If you call pct with an argument and the GPIB 232CT is not CIC
37. receives XON GPIB 232CT User Manual C 8 National Instruments Corp Appendix D Operation of the GPIB The GPIB is a link bus or interface system through which interconnected electronic devices communicate Hewlett Packard invented the GPIB which they call the HP IB to connect and control programmable instruments manufactured by them Because of its high system data rate ceilings of from 250 kbytes sec to 1 Mbytes sec the GPIB quickly became popular in other applications such as intercomputer communication and peripheral control It was later accepted as the industry standard IEEE 488 The versatility of the system prompted the name General Purpose Interface Bus Types of Messages The GPIB carries device dependent messages and interface messages e Device dependent messages often called data or data messages contain device specific information such as programming instructions measurement results machine status and data files e Interface messages manage the bus itself They are usually called commands or command messages Interface messages perform such tasks as initializing the bus addressing and unaddressing devices and setting device modes for remote or local programming The term command as used here should not be confused with some device instructions that can also be called commands Such device specific instructions are actually data messages Talkers Listeners and Controllers A Talker sends data messages
38. return This programming message tells the GPIB 232CT to assert the EOI line when it sends the end of string character linefeed The second line of the example is a GPIB PC function call provided as part of a National Instruments product that allows a personal computer to control the GPIB from Microsoft BASIC This function outputs the string in WRTS to the device GPIB 232CT National Instruments Corp 7 1 GPIB 232CT User Manual Programming in G Mode Chapter 7 You can enter programming messages in any combination of uppercase and lowercase letters How Messages are Processed The GPIB 232CT processes each programming message on a line by line basis The GPIB 232CT buffers the entire message interprets the function name and arguments then executes the message Function Names The function names have been selected to indicate each function s purpose thereby making your programs easy to understand However if you wish to reduce some overhead in your program and do not mind giving up these advantages you can use only as much of the function name as is necessary to distinguish it from other functions This abbreviated form of the function name is shown in boldface in the function tables and in the syntax portions of the function descriptions Function Argument Delimiters When you type in a function separate the first argument from the function name with at least one space Separate each additional argument with at least one space
39. some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted National Instruments Corp 5 55 GPIB 232CT User Manual S Mode Functions Chapter 5 Example 1 PRINT 1 trg 2 10 4 5 7 Trigger 3 devices GPIB 232CT User Manual 5 56 National Instruments Corp Chapter 5 S Mode Functions wait Wait for Selected Event Type Syntax Purpose Remarks General Use function wait mask lt CR gt You use wait to monitor selected GPIB events and to delay any further GPIB 232CT activity until any of them occur The argument mask is a numeric string that specifies the events to wait for The numeric string represents a bit mask containing a subset of the same bit assignments as the status word described in the stat function Each bit is set or cleared to wait or not to wait respectively for the corresponding event to occur The numeric string can be expressed as decimal octal or hexadecimal After receiving the wait programming message the GPIB 232CT monitors GPIB activity When any event corresponding to the bits set in mask occurs the GPIB 232CT returns status information indicating its current status If continuous status reporting has been enabled status will be reported in the format requested If continuous status has not been enabled status will be returned in numeric format You could use wait for
40. specifies whether the GPIB 232CT has detected a device trigger command The DTAS bit is set whenever the GPIB 232CT as a Listener detects the Group Execute Trigger GET command has been sent by another Controller The DTAS bit is cleared in status at the start of any subsequent programming message S 1 The DCAS bit specifies whether the GPIB 232CT has detected a device clear command The DCAS bit is set whenever the GPIB 232CT detects the Device Clear DCL command has been sent by itself or by another Controller or whenever the GPIB 232CT as a Listener detects the Selected Device Clear SDC command has been sent by itself or by another Controller The DCAS bit is cleared in status at the start of any subsequent programming message GPIB 232CT User Manual B 4 National Instruments Corp Appendix B Status Information In addition to the previously described conditions the following situations also affect the bits in status e Acallto the on1 function clears the following bits END TACS LOK LACS REM DTAS CIC DCAS e Acallto on1 affects bits other than those listed here according to the rules explained for each bit National Instruments Corp B 5 GPIB 232CT User Manual Status Information Appendix B GPIB Error Codes When the ERR bit is set in status a GPIB error or a serial port error has occurred The error code is indicated by GPIB error or serial error The following paragraphs describe t
41. the ppr s argument for each of them is 0 1 Thus the configuration byte for each of them is 01101000 hex 68 When a parallel poll is conducted the Controller can immediately find out if all line printers are free because the response in this situation will be 0 If any line printer is busy bit 0 of the parallel poll response will be 1 corresponding to DIO line 1 being asserted However what if the Active Controller wants to know if one line printer is free If the Controller reconfigures the line printers to respond positively when free dio s 0 0 configuration byte 01100000 then if any device is free it will drive the DIO line to 1 Thus the Controller can use S bit IST bit correspondence for different types of information GPIB 232CT User Manual F 4 National Instruments Corp Appendix G Setting Switches This appendix explains how to set the configuration switch of the GPIB 232CT when operating in S mode As shown in Chapter 3 switch 1 is placed down or off to operate in S mode Set the remaining switches to match the characteristics of the terminal or computer you will attach to the other end of the serial cable Often you can change the serial port characteristics of the terminal or computer by setting switches running a utility program or from within BASIC Determine the default characteristics of your computer or terminal s serial port If you want to change the configuration on that side do so before at
42. the value of the device s individual status bit to determine whether to drive the line true or false Each group of addr ppr s can be separated by either a comma or space just as any list of arguments If you call ppc without an argument the GPIB 232CT records the EARG error If this is the first function you call that requires GPIB Controller capability and you have not disabled System National Instruments Corp 5 27 GPIB 232CT User Manual S Mode Functions Chapter 5 See Also Example Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable If you passed control to some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted The GPIB 232CT takes the arguments ppr and s and constructs the appropriate parallel poll enable PPE message for each addr specified When addr is the address of the GPIB 232CT the GPIB 232CT programs itself to respond to a parallel poll by setting its local poll enable LPE message to the value specified ist ppu rpp and Appendix F Parallel Polling 1 PRINT 1 PPC 18 23 8 0 23 10 7 1 Configure 2 devices for parallel poll PRINT 1 RPP Conduct a Parallel poll of 2 devices configured above response 192 lt CR gt lt LF gt both devices responded positively INPUT
43. to one or more Listeners The Controller manages the flow of information on the GPIB by sending commands to all devices National Instruments Corp D 1 GPIB 232CT User Manual Operation of the GPIB Appendix D Devices can be Listeners Talkers and or Controllers A digital voltmeter for example is a Talker when sending measurements and is a Listener when receiving programming messages The GPIB is a bus like an ordinary computer bus except that the computer has its circuit cards interconnected via a backplane bus whereas the GPIB has stand alone devices interconnected via a cable bus The role of the GPIB Controller can also be compared to the role of the CPU of a computer but a better analogy is to the switching center of a city telephone system The switching center Controller monitors the communications network GPIB When the center Controller notices that a party device wants to make a call send a data message it connects the caller Talker to the receiver Listener The Controller addresses a Talker and a Listener before the Talker can send its message to the Listener After the message is transmitted the Controller can unaddress both devices Some bus configurations do not require a Controller For example one device can always be a Talker called a Talk only device and there can be one or more Listen only devices A Controller is necessary when the active or addressed Talker or Listener must be changed Th
44. to the GPIB 232CT you must address the GPIB 232CT The GPIB software you use on the Controller side can provide high level calls that perform this addressing automatically GPIB 232CT User Manual H 10 National Instruments Corp Appendix H Sample Programs Using a Serial HP 7475A Plotter with a GPIB Controller This is a program to draw a circle using an HP 7475A Color Plotter with a serial interface The Controller is an IBM PC with the National Instruments GPIB PC card and software Getting Ready to Program First set up the GPIB 232CT configuration switches with a primary address of 2 as shown in Figure H 4 ECLA Figure H 4 G mode primary GPIB address 2 Next connect the GPIB cable to the GPIB port on your computer and to the GPIB 232CT Connect the serial cable to the serial port on your device and to the GPIB 232CT Power on the GPIB 232CT The serial port characteristics of the GPIB 232CT and the serial device must be exactly the same In this case the plotter s serial port settings are as follows e baud rate 9600 e parity none e databits 7 e stop bits 1 National Instruments Corp H 11 GPIB 232CT User Manual Sample Programs Appendix H The GPIB 232CT s default serial port characteristics however are as follows e baud rate 9600 e parity none e databits 8 e stop bits 1 The number of data bits do not match so the default setting of the GPIB 232CT must be changed before you read or writ
45. 00 microseconds initializes the GPIB and makes the interface board become CIC When needed sic is generally used at the beginning of a program to make the GPIB 232CT CIC and is used when a bus fault condition is suspected The IFC signal resets only the GPIB interface functions of bus devices and not the internal device functions Device functions are reset with the clr programming message To determine the effect of these messages consult the device documentation If you are in a debugging environment you may want to vary the amount of time IFC is asserted For example you may set time to 10 seconds to allow you to check on a bus analyzer that IFC is actually being asserted Otherwise you do not need to include the time argument The GPIB 232CT records the ESAC error if you have disabled its System Controller capability with the rsc function It records the EARG error if you specify a time outside the range 0001 to 3600 GPIB 232CT User Manual 5 42 National Instruments Corp Chapter 5 S Mode Functions See Also clr and Appendix D Examples 1 PRINT 1 sic Send interface clear for 500 microseconds 2 PRINT 1 SIC 01 Send interface clear for 10 milliseconds National Instruments Corp 5 43 GPIB 232CT User Manual S Mode Functions Chapter 5 spign Ignore Serial Port Errors Type Syntax Purpose Remarks See Also Serial Port function spign bool lt CR gt You use spi
46. 1 How Messages are Processed cesccseseeeeseeeeneeeeeeees 7 2 Function Names cscccsccsseeseceseeseeeeeessecesecenecseeeseeeeeeaeeneenaees 7 2 Function Argument Delimiters cccceeseeseeseeeeeeeeeeseeeneeesees 7 2 Abbreviation for Argument c cecceeseeeeeeeeeteeeeeees 7 2 Status Informations ienes rs an EAR e E 7 3 Communicating with the GPIB 232CT and the Serial Device 7 3 Address of the GPIB 232CT n se 7 3 Address of the Serial Device n 7 3 Addressing Terminology s es 7 3 The GPIB 232CT and Serial Device as Listener eee 7 4 The GPIB 232CT and Serial Device as Talker 7 5 GPIB Read and Write Termination END and EOS 7 6 Serial Port Transmissions ririri oian vsti series ierinoisi riss 7 6 G Mode Default Settings s eseeeeeeseeeeeeeeerereeesrereersrsrererrerereees 7 7 List of G Mode Functions by Group s eeeseseeseseeeeeereerersrereerees 7 8 GPIB Configuration Functions sseeeeeeeeeeeeeeeeeeeeeeee 7 8 Serial Port Configuration Functions eee 7 9 General Use Functions ee eeeeseeseeseeeseeeeeeeeeees 7 9 List of G Mode Functions in Alphabetical Order 7 10 Operation of the GPIB 232CT with a Serial Device 7 10 Serial Poll 2 3 gain tsessniacianiniG andi Rata 7 11 Service Request iis c2c3 c cstsies aag e n aaa 7 11 National Instruments Corp xiii GPIB 232CT User Manual Contents Parallel Poll sicssccsec
47. 1 PPR Assign parallel poll response to integer variable GPIB 232CT User Manual 5 28 National Instruments Corp Chapter 5 S Mode Functions ppu Parallel Poll Unconfigure Type Syntax Purpose Remarks Parallel Poll function ppu alist lt CR gt You use ppu if you are performing parallel polls and you wish to prevent certain devices from responding The argument alist isa list of addrs that are separated by commas or spaces addrs are device addresses that specify the GPIB addresses of the device or devices to be disabled from parallel polls A device address consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary address Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 If you call ppu with alist the GPIB 232CT unconfigures from parallel polls only those devices specified in alist If you call ppu without alist the GPIB 232CT unconfigures all devices from parallel polls If this is the first function y
48. 10 User Manual 7 6 National Instruments Corp Chapter 7 Programming in G Mode information After the serial error code has been reported it will be reset automatically so that no further action to the GPIB 232CT is necessary You can also determine if a serial port error has occurred by performing a serial poll of the GPIB 232CT and checking the serial poll response byte to see if its ESDR bit is set Refer to the section on serial poll responses at the end of this chapter G Mode Default Settings Tables 7 1 and 7 2 list power on characteristics of the GPIB 232CT and the functions you can use to change those characteristics Table 7 1 GPIB Characteristics Ee e ee el O Power on Characteristic Value Function End of string modes none eos Allow GPIB 232CT to assert SRQ Table 7 2 Serial Port Characteristics Power on Characteristic Value Function Echo bytes to serial port no echo Enable serial port communication yes onl Baud rate 9600 spset Parity none spset Data bits 8 spset Stop bits 1 spset continues National Instruments Corp 7 7 GPIB 232CT User Manual Programming in G Mode Chapter 7 Table 7 2 Serial Port Characteristics continued Characteristic Function Send XON XOFF n xon xon o Recognize XON XOFF no List of G Mode Functions by Group Tables 7 3 through 7 5 contain the programming messages that are sent to the GPIB 232CT from a GPIB Talker to confi
49. 3 caddr Change the GPIB Address of the GPIB 232CT 5 4 clr Clear Specified Device ecccesceeceesseeseeeeeeseeeeeeaeeeeeeaeens 5 6 cmd Send GPIB Commands eeeeeeseceeseeeseeeeseeeeneeeeneeeeee 5 8 echo Echo Characters Received from Serial Port 5 11 eos Change Disable GPIB EOS Termination Mode 5 12 eot Enable Disable END Message on GPIB Writes 5 15 gts Go from Active Controller to Standby ceeeeeeeeeees 5 17 ibcl Enter ibcl Operating System oo eeeeeeeeeeeeeeeeeeeeenes 5 19 id Identify System ccccccescssssssesessaesetssetesetecceecesceseseverseee 5 21 ist Set or Clear Individual Status Bit eee eeeeseeereeereeeees 5 22 LOG GONG OCA succes o e erea e aaee oaan 5 23 onl Place the GPIB 232CT Online Offline cece 5 25 pct Pass Control ce ivaten ied a eden wien Ooh eet uin ete 5 26 ppc Parallel Poll Configure eee eceseeseeseeeeeeeeseeeeceeeeeeeees 5 27 ppu Parallel Poll Unconfigure 0 0 0 eee sseesesseeteeseeeeeeeeeees 5 29 rd Read Datania aa Sohne a cides de aE ASS 5 31 rpp Request Conduct a Parallel Poll eeeeeeeees 5 34 rsc Request System Control sessesseeseresesreesesrsereresresresreerses 5 36 rsp Request Conduct a Serial Poll ee eeeeeeeeeeteees 5 38 rsv Request Service Set or Change Serial Poll Status Byte 5 41 sic Send Interface Clear ccecceeccesseeseeeseeeeeeeeesee
50. 6 MSA30 PPD 5F 137 95 _ UNT 7F 177 127 DEL PPE Parallel Poll Enable SPE Serial Poll Enable PPU Parallel Poll Unconfigure TCT Take Control SDC Selected Device Clear UNL Unlisten SPD Serial Poll Disable UNT Untalk National Instruments Corp A 3 GPIB 232CT User Manual Multiline Interface Messages Mnemonic Message Appendix A Interface Message Reference List Interface Function s LOCAL MESSAGES RECEIVED by interface functions gts ist lon Ipe ltn lun nba pon rdy rpp rsc TSV rtl sic sre tca tes ton go to standby individual status qualifier listen only local poll enable listen local unlisten new byte available power on ready request parallel poll request system control request service return to local send interface clear send remote enable take control asynchronously take control synchronously talk only REMOTE MESSAGES RECEIVED ATN DAB DAC DAV DCL END GET GTL IDY IFC LLO MLA MLA MSA or MSA MTA MTA OSA OTA PCG GPIB 232CT User Manual attention data byte data accepted data valid device clear end group execute trigger go to local identify interface clear local lockout my listen address my listen address my secondary address my talk address my talk address other secondary address other talk address primary command group A 4 C PP L LE PP L LE L LE SH SH AH T TE L LE SR RL PP C
51. AH SH via C via C via C C C via via C via C via C via via C via C via C via C via C PP via C C AH GPIB 232CT User Manual Multiline Interface Messages Appendix A Interface Message Reference List continued Mnemonic Message Interface Function s REMOTE MESSAGES SENT continued RQS request service T TE SDC selected device clear via C SPD serial poll disable via C SPE serial poll enable via C SRQ service request SR STB status byte via T TE TCT take control via C UNL unlisten via C UNT untalk via C GPIB 232CT User Manual A 6 National Instruments Corp Appendix B Status and Message Information This appendix describes the status and error information that the GPIB 232CT records as it executes each programming message Items that apply to S mode are marked with an S Items that apply to G mode are marked with a G The number preceding each description is the numeric value of that bit in the status word or of the error code Status Bits The following paragraphs describe the conditions represented by the bits in status ERR TIMO S G 32768 The ERR bit is set in status following any call that results in an error the particular error can be determined by examining the GPIB error and serial error values The ERR bit is cleared following any call that does not result in an error By examining this bit you can check for an error conditi
52. B 232CT User Manual 8 12 National Instruments Corp Chapter 8 G Mode Functions To determine the mask value you want add up the bit values of each of the conditions on which you want SRQ to be asserted For example if you want SRQ asserted on GPIB errors and serial port errors you will call srqen with a mask of 12 4 for GERR and 8 for SERR The power on default of srqen is disabled that is SRQ will never be asserted If you call srqen without an argument the GPIB 232CT returns a decimal string that indicates the decimal value of the current setting See Also eos Examples 1 WRTS srqen 0 CHRS 13 Never assert SRQ CALL IBWRT GPIB232 WRTS 2 WRT srqen 4 CHRS 13 Assert SRO when CALL IBWRT GPIB232 WRTS ENOL occurs National Instruments Corp 8 13 GPIB 232CT User Manual G Mode Functions Chapter 8 stat Return GPIB 232CT Status Type Syntax Purpose Remarks General Use function stat c n lt CR gt or stat c s lt CR gt or stat c n s lt CR gt You use stat to obtain the status of the GPIB 232CT to see if certain conditions are currently present You use stat most often to see if the previous operation resulted in an error The GPIB 232CT returns status information to you in a form depending on the mode or combination of modes you chose n indicates that the status information will be returned as numeric strings s indicates that
53. CT is not System Controller the GPIB 232CT records the ESAC error See Also Appendix B for more error information Examples 1 PRINT 1 loc 6 22 4 23 7 Put 3 devices in local mode 2 PRINT 1 LOC Put all devices in local mode GPIB 232CT User Manual 5 24 National Instruments Corp Chapter 5 S Mode Functions onl Place the GPIB 232CT Online Offline Type Initialization function Syntax onl bool lt CR gt Purpose You use on1 to disable communications between the GPIB 232CT and the GPIB or to reinitialize the GPIB 232CT characteristics to their default values Remarks Ifthe argument bool is 1 the GPIB 232CT places itself online If the argument bool is 0 the GPIB 232CT places itself offline By default the GPIB 232CT powers up online is in the Idle Controller state and configures itself to be the System Controller If you call on1 without an argument the GPIB 232CT returns the current status of the GPIB 232CT which is 0 if the GPIB 232CT is offline and 1 if the GPIB 232CT is online Placing the GPIB 232CT offline can be thought of as disconnecting its GPIB cable from the other GPIB devices Placing the GPIB 232CT online allows the GPIB 232CT to communicate over the GPIB and also restores all GPIB 232CT settings to their power on values See Also Tables 4 1 and 4 2 for the GPIB 232CT power on settings Examples 1 PRINT 1 onl1 1 Put the GPIB 232CT online and restore its
54. Characteristics ccccccccccccsssssssssccsessessseeseees 4 6 Table 4 2 GPIB Characteristics cccccccscsssssssscccssessscssseeseseeeeseeeees 4 6 Table 4 3 FVO Functions et teeea canes detec he LAER heed Bice 4 7 Table 4 4 Bus Management Functions c cccccesceeseeceeeeeeeeeeees 4 7 Table 4 5 GPIB Initialization Functions ccec ccc ceceeseeseseeeeees 4 8 Table 4 6 Serial Poll Functions 0 ccccccecscccccceesssssscccesssssssseseseeees 4 8 Table 4 7 Low Level Controller Functions cccccccsessssceeeeeeeneee 4 9 Table 4 8 Parallel Poll Functions 0 cccccccssssssccsesssssssssseseessssseeees 4 9 Table 4 9 Serial Port Initialization Functions ccccccccccseeseseessees 4 10 Table 4 10 General Use Functions ccccccccccccssssssccceesssssssesseeeees 4 10 Table 4 11 GPIB 232CT Functions ccceeecssscccecessssssescseseesees 4 11 Table 5 1 Data Transfer Termination Methods ccccccceeeeeeees 5 12 Table 5 2 GPIB Status Conditions 0 cccccccccccssssssseeseeseeeseseeeeees 5 48 Table 5 3 GPIB Error Conditions cccccccecsccccesssssssessceseesssseeeees 5 49 Table 5 4 Serial Port Error Conditions 0 ccccccccccsccsssseseseeeeeeeees 5 50 Table 5 5 Wait Mask Value ccccccccccccceessssssccceesssssesssssseeseeees 5 58 Table 6 1 Primary Address Configurations 0 0 0 eeeseseeeeereereeees 6 4 Table 7 1 GPIB Characteristics cicccccccccccsessss
55. F gt PRINT 1 rd 10 5 Read 10 bytes from device 5 into serial port buffer RESPS INPUTS 10 1 Tnput 10 bytes from serial port buffer LINE INPUT 1 COUNTS Input string that indicates number of bytes actually read from GPIB PRINT COUNTS bytes were read from GPIB Print number of bytes that were read from the GPIB 2 PRINT 1 EOS X 13 Send EOI with lt CR gt on wrt do not terminate when lt CR gt is detected on rd compare 7 bits PRINT 1 wrt 10 5 GPIB 232CT sends EOI with lt CR gt CHRS 13 to tell Listeners that this is the last byte of data PRINT 1 012345678 3 PRINT 1 eos What are the current EOS settings response X 13 lt CR gt lt LF gt GPIB 232CT User Manual 5 14 National Instruments Corp Chapter 5 S Mode Functions eot Enable Disable END Message on GPIB Writes Type Syntax Purpose Remarks See Also Initialization function eot bool lt CR gt You use eot at the beginning of your program if you wish to change how the GPIB 232CT terminates GPIB writes Using eot you tell the GPIB 232CT to automatically send or not send the GPIB END message with the last byte that it writes to the GPIB If the argument bool is 1 the GPIB 232CT automatically sends the END message with the last byte of each wrt If the argument bool is 0 END is not sent The power on default is 1 If you call eot withou
56. Functions Chapter 4 Table 4 9 Serial Port Initialization Functions Function Purpose ECHO on off Echo characters received from serial port SPIGN on off Ignore serial port errors XON modes General Use Functions Change serial port XON XOFF protocol Table 4 10 General Use Functions Function Purpose Switch to IBCL operating system ID Identify system STAT modes Return GPIB 232CT status WAIT mask GPIB 232CT User Manual Wait for selected event s 4 10 National Instruments Corp Chapter 4 Programming in S Mode Alphabetical List of S Mode Functions The following is an alphabetical list of all functions Table 4 11 GPIB 232CT Functions Function Purpose CAC mode Become Active Controller CADDR address Change the IEEE 488 address of the GPIB 232CT CLR address list Clear specified device s CMD count commands Send IEEE 488 commands ECHO on off Echo characters received from serial port EOS modes eoschar EOT on off Change or disable GPIB end of string termination mode Enable or disable END termination message on GPIB write operations GTS mode Go from Active Controller to Standby IBCL Switch to IBCL operating system ID Identify system IST set clear Set or clear individual status bit for use in GPIB 232CT response to Parallel Polls LOC address list Go to Local ONL on off National Instruments Corp Place the GPIB 232CT onl
57. G Mode Functions Chapter 8 spset Change Serial Port Parameters Type Syntax Purpose Remarks Serial Port Configuration function spset baud parity databits stopbits lt CR gt You use spset at the beginning of your program to set up the GPIB 232CT serial port characteristics baud rate parity data bits and stop bits to those required by your serial device The argument baud is a numeric string specifying the baud rate 300 600 1200 2400 4800 9600 19200 38400 The argument parity is a character specifying the parity e for even o for odd n for none The argument databits is a character specifying the number of data bits 7 or 8 The argument stopbits is a character specifying the number of stop bits 1 or 2 Until you call spset the following characteristics are in effect 9600 n 8 1 meaning the baud rate is 9600 bits per second bps parity is disabled there are 8 data bits and 1 stop bit If you must reconfigure the GPIB 232CT s serial port do so only when communication with the serial port is not taking place If you call spset without an argument the GPIB 232CT returns to you its current serial port configuration GPIB 232CT User Manual 8 10 National Instruments Corp Chapter 8 G Mode Functions Examples 1 REM Set up the serial port of GPIB 232CT to keep REM its current baud rate current parity and REM to use 7 data bits and 2 stop bits WRTS spset 7 2 CHRS
58. GPIB 232CT User Manual MicroGPIB RS 232 to TIEEE 488 Controller July 1992 Edition Part Number 320114 01 Copyright 1988 1992 National Instruments Corporation All Rights Reserved National Instruments Corporate Headquarters 6504 Bridge Point Parkway Austin TX 78730 5039 512 794 0100 800 IEEE 488 toll free U S and Canada Technical support fax 512 794 5678 Branch Offices Australia 03 879 9422 Belgium 02 757 00 20 Canada 519 622 9310 Denmark 45 76 73 22 France 1 48 65 33 70 Germany 089 714 5093 Italy 02 48301892 Japan 03 3788 1921 Netherlands 01720 45761 Norway 03 846866 Spain 91 896 0675 Sweden 08 984970 Switzerland 056 45 58 80 U K 0635 523 545 MicroGPIB Products National Instruments has developed the MicroGPIB product line to offer a series of high performance low cost IEEE 488 support items packaged in small all metal cases capable of being rack mounted Limited Warranty The GPIB 232CT 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 wor
59. GPIB Talkers and Listeners can identify the last byte of data messages END and EOS The two methods permit a Talker to send data messages of any length without the Listener s knowing in advance the number of bytes in the transmission END message The Talker asserts the EOI End or Identify signal simultaneously with transmission of the last data byte The Listener stops reading when it detects a data message accompanied by EOI regardless of the value of the byte EOS character The Talker uses a special character at the end of its data string The Listener stops receiving data when it detects that character Either a 7 bit ASCII character or a full 8 bit binary byte can be used The two methods can be used individually or in combination It is important that the Listener be configured to detect the end of a transmission When the GPIB 232CT receives its own talk or listen address no EOS modes are in effect When talking the GPIB 232CT asserts EOI with the last byte of its response When the GPIB 232CT receives the serial device talk address the EOS modes in effect are those that you select using the eos function Serial Port Transmission The GPIB 232CT checks the data received from the serial device for errors while buffering data If a serial port error occurs the GPIB 232CT records the appropriate error code in its status area To determine if a serial port error has occurred use stat to request the GPIB 232CT status GPIB 6
60. IB 232CT then returns to you the 4 data bytes followed by 6 null bytes followed by an ASCII 4 and lt CR gt lt LF gt A null byte is decimal 0 You should always read back count bytes of data from the serial port then look at the remaining bytes to determine how many of the count bytes were read from the GPIB Refer to the example at the end of this description The GPIB 232CT aborts the GPIB read and records the EABO error if at any time during the GPIB read the time limit set for I O functions expires This limit is 10 seconds unless you use tmo to change it If the GPIB 232CT is CIC rd will cause the GPIB 232CT to address itself to listen if it is not already addressed If you specify the address of the Talker the GPIB 232CT will also address that device to talk If you do not specify the address of the Talker the GPIB 232CT will assume that the Talker has already been addressed The GPIB 232CT then places itself in Standby Controller state with ATN off and remains there after the read operation is completed If you specify an address the GPIB 232CT must be CIC to perform the addressing If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable If you call rd with the address argument and you previously passed control to some other GPIB device
61. IB 232CT to be System Controller Disable system control What is the current System Controller status GPIB 232CT is not the System Controller 5 37 GPIB 232CT User Manual S Mode Functions Chapter 5 rsp Request Conduct a Serial Poll Type Syntax Purpose Remarks Serial Poll function rsp alist lt CR gt You use rsp if you wish to conduct a serial poll to obtain device specific status information from one or more devices The argument alist isa list of addrs that are separated by commas or spaces addrs are device addresses that specify the GPIB addresses you wish to poll A device address consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary addresses Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 rsp serially polls the specified devices to obtain their status bytes If bit 6 the hex 40 or RQS bit of a device s response is set its status response is positive that is that device is requesting ser
62. IB PC to Serial Printer cccceeeseeneees H 14 Getting Ready to Program 0 tee eee eeeeeseeereteeeeeee H 14 Programming Steps cee eeeeseeseceeeeeeseeeeseeeseeeseees H 15 Step 1 stat Function eee eects H 15 Step 2 GPIB Initialization Functions H 15 Step 3 Serial Port Initialization Functions 00 0 eee eeeeeeeeeeeeee H 15 Step 4 Communicate with the Printer H 15 GPIB 232CT User Manual xvi National Instruments Corp Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure National Instruments Corp Contents Figures Th GPIB 232CT ninae amuse 1 1 The GPIB 232CT Front Panel eee eeeeeeeeneeees 1 5 The GPIB 232CT Rear Panel eee eeeeeeeereeeeeeee 1 7 The RS 232 Connector and Signal Designations 1 8 The GPIB Connector and Signal Designations 1 9 Personal Computer Controlling a GPIB Plotter 2 2 A Serial Printer Connected to a GPIB Controller 2 2 S Mode Switch Settings cess eseeseeseeneeeetseeseeseeees 3 3 Factory Default Settings for Switch U22 wee 3 4 G Mode Switch Settings eee ecceseeseeneeseenecneeeeeeeeees 6 3 Example Settings for Switch U22 seses 6 6 DTE to DCE Cable Configuration C 3 Minimum DTE to DCE Cable Configuration
63. Manual The Serial Connection Appendix C If your serial device does not use the same hardware handshaking protocol as the GPIB 232CT you can use a minimum configuration null modem cable and use XON XOFF handshaking if necessary Or you can use a custom cable that will satisfy the GPIB 232CT hardware handshaking protocol Figure C 4 shows the connections for a minimum configuration null modem cable In Figure C 4 the GPIB 232CT connector is on the left Figure C 4 Minimum Null Modem Cable Configuration If a custom cable is required for your application review your serial device s RS 232 characteristics and build the cable to perform the desired functions Buffering and Handshaking The GPIB 232CT is able to accept serial data faster than it is able to process it Two protection mechanisms are used to ensure that the GPIB 232CT does not lose incoming data data buffering and handshaking The GPIB 232CT has an internal RAM buffer that stores incoming serial data and serial port error information until it can process the data and if necessary output the data to the GPIB port The size of this RAM buffer in part determines how much serial data the GPIB 232CT can accept until GPIB 232CT User Manual C 6 National Instruments Corp Appendix C The Serial Connection its buffer overflows The GPIB 232CT comes equipped with either a 64K RAM buffer or a 256K RAM buffer 32K of which is used for the serial input buffer When it
64. PIB 232CT has all the software and logic required to implement the physical and electrical specifications of the IEEE 488 and the RS 232 standards It is capable of both interpreting and executing high level commands that you send to it over the serial port and performing GPIB to RS 232 protocol conversion GPmp 232cT EC 448 CD RSI CON ete e o o 0 A POWER MEADY TALK LISIEN siu Figure 1 1 The GPIB 232CT National Instruments Corp 1 1 GPIB 232CT User Manual Description of the GPIB 232CT Chapter 1 What Your Kit Contains Your kit should contain the following components Component Part Number One of the following boxes GPIB 232CT 64K RAM 115 VAC 776173 01 GPIB 232CT 256K RAM 115 VAC 776173 02 GPIB 232CT 64K RAM 230 VAC 776173 31 GPIB 232CT 256K RAM 230 VAC 776173 32 GPIB 232CT User Manual 320114 01 GPIB CT IBCL Reference Manual 320132 01 GPIB 232CT User Manual 1 2 National Instruments Corp Chapter 1 Description of the GPIB 232CT Optional Equipment Component Part Number Rackmount Kit Single 1 unit 180480 01 Dual 2 units 180480 02 RS 232 Shielded Cables Compatible with IBM PC DTE to DTE 2m 180459 02 DTE to DTE 4m 181459 04 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 National Instruments Corp 1 3 GPIB 232CT User Manual Description of the GPIB 232CT Cha
65. PIB system should be System Controller If the argument bool is 1 the GPIB 232CT configures itself to be the GPIB System Controller If the argument bool is 0 the GPIB 232CT configures itself as not System Controller If you call rsc without an argument the GPIB 232CT returns to you its System Controller status which is 0 if the GPIB 232CT is not currently System Controller or 1 if the GPIB 232CT is System Controller As System Controller the GPIB 232CT can send the Interface Clear IFC and Remote Enable REN messages to GPIB devices If some other Controller asserts Interface Clear the GPIB 232CT cannot respond unless it is configured as not System Controller In most applications the GPIB 232CT will be System Controller In some applications the GPIB 232CT will never be System Controller In either case rsc is used only if the computer is not going to be System Controller while the program executes The IEEE 488 standard does not specifically allow schemes in which System Control can be passed from one device to another however rsc could be used in such a scheme The GPIB 232CT configures itself to be System Controller at power on sic and sre GPIB 232CT User Manual 5 36 National Instruments Corp Chapter 5 Examples 1 PRINT 2 PRINT 3 PRINT response rse 1 rec 0 rsc 0 lt CR gt lt LF gt National Instruments Corp S Mode Functions Enable GP
66. S 232 standard write to EIA Engineering Department Standards Sales Office 2001 Eye Street N W Washington D C 20006 RS 232C 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 Since then many manufacturers of computers and instruments have adopted the standard for their serial communications needs The RS 232 serial port on the GPIB 232CT uses a 25 pin D subminiature connector with a DTE Data Terminal Equipment interface configuration That is the GPIB 232CT transmits data on pin 2 and receives data on pin 3 Table C 1 shows the signal lines supported on the GPIB 232CT National Instruments Corp C 1 GPIB 232CT User Manual The Serial Connection Appendix C Table C 1 RS 232 Serial Port Pinouts Signal Name Function AA 1 PG This line is connected to the chassis Protective ground of the GPIB 232CT Ground BA 2 TxD This line carries serial data from the Transmit Data GPIB 232CT to the serial host RxD This line carries serial data from the Receive Data serial host to the GPIB 232CT CA 4 RTS This signal line is asserted by the Request to GPIB 232CT when it is ready to
67. Send accept serial data over the RS 232 RTS is unasserted when the GPIB 232CT is no longer ready to accept serial data CB 5 CTS This signal line is asserted by the Clear to Send serial host and sensed by the GPIB 232CT It indicates that the serial host is ready to accept data When CTS is unasserted data transmission from the GPIB 232CT is disabled SG This line establishes a reference Signal Ground point for all interface voltages DTR This signal line is asserted by the Data Terminal GPIB 232CT when it is powered on Ready It can be used to notify the other serial device that the GPIB 232CT has been powered on or it could be used to wrap back to the GPIB 232CT CTS input if no hardware handshake is used GPIB 232CT User Manual C 2 National Instruments Corp Appendix C The Serial Connection To interface other products to your GPIB 232CT RS 232 serial port consult your serial device manual to determine if the device is configured as a DTE or DCE Also note how the control lines are used and whether they must be driven for the serial port to operate The GPIB 232CT s CTS line must be driven either by the GPIB 232CT s DTR line or by a signal line from the serial device used to implement a hardware handshake for data The following discussions contain some cabling examples from the GPIB 232CT to a serial host device Interfacing the GPIB 232CT to a DCE A correctly configured DTE DCE interface
68. T 1 wrt 50 9 97 FOR I 1 TO 50 PRINT 1 CHRS A I NEXT I PRINT 1 CHRS 13 2 PRINT 1 wrt 2 PRINT 1 ABCDE GPIB 232CT User Manual Wri Chapter 5 Write 50 bytes to device at primary address 9 and secondary address 97 Send carriage return te the data bytes ABCDE at device at address 2 5 62 National Instruments Corp Chapter 5 S Mode Functions xon Change Serial Port XON XOFF Protocol Type Syntax Purpose Remarks Serial Port function xon booltx boolrx lt CR gt You use xon at the beginning of your program to configure the GPIB 232CT to communicate over the serial port using the same XON XOFF protocol as your serial device The argument booltx specifies whether to enable the XON XOFF protocol when sending data out on the serial port If the argument boo1tx is a 1 the GPIB 232CT monitors its serial receive buffer for XON XOFF characters as it sends data over the serial port If it receives the XOFF character decimal 19 or lt CTRL gt s it will immediately stop sending data When it receives the XON character decimal 17 or lt CTRL gt q it begins sending data again If you want to send a data string that may contain a lt CTRL gt s or lt CTRL gt q you must disable bool tx The argument boolrx specifies whether to enable the XON XOFF protocol when receiving data over the serial port If the argument boolrx is a 1 and
69. User Manual Parallel Polling Appendix F busy and 0 when it is free or vice versa Consult your device documentation for this information With this information the Controller can configure devices according to the information desired Only the Active Controller can perform a parallel poll There are two steps to conducting a parallel poll the following configuration step and the actual polling The following paragraphs describe these two steps Configuration In the S Mode the ppc function configures devices for parallel polls For example if you want to configure a device at address 5 to respond on DIO line 3 when the IST bit is 1 the programming message would be ppc 5 3 1 The GPIB 232CT takes the arguments 3 1 and constructs the following parallel poll enable byte U S DIO lines 1 8 0 1 1 0 1 0 1 0 The value of this byte is hex 6A where Enable Thus when IST 1 the device will assert DIO line 3 which corresponds to 010 in bits 0 2 The ppc function sends the device s listen address Parallel Poll Configure hex 6A then unlisten The Active Controller can configure itself to respond to a parallel poll using ppc also This might be used in the case where the GPIB 232CT is not the System Controller and the System Controller does not have the capability to do the configuration Since the GPIB 232CT cannot be the Controller in the G Mode the GPIB Controller in your system must configure the GPIB 232CT in ord
70. adio noise emissions from digital apparatus set out in the Radio Interference Regulations of the Canadian Department of Communication DOC These regulations are designed to provide reasonable protection against interference from the equipment to radio and television reception in commercial areas 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 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 Relocate the equipment with respect to the receiver e Reorient 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 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
71. agement functions do not meet the needs of your device cmd gives you precise control over the GPIB For example in applications that require command sequences not sent by other functions you can use cmd to transmit any sequence of interface messages commands over the GPIB The argument count is a numeric string preceded by a number sign count specifies the number of GPIB command bytes interface messages to send which is a number between 1 and 255 The number of command bytes must not include the carriage return lt CR gt or linefeed lt LF gt that you include to indicate the end of the programming message The argument commands is a list of GPIB commands These commands are represented by their ASCII character equivalents For example the GPIB Untalk UNT command is the ASCII character underscore _ If you call cmd without count the GPIB 232CT recognizes the end of the command string when it sees a lt CR gt or an lt LF gt count is required only if the command string contains a lt CR gt or an lt LF gt character However a lt CR gt or an lt LF gt in the command string would be unusual since neither of these is a defined GPIB command The GPIB commands or interface messages are listed in Appendix A They include device talk and listen addresses secondary addresses messages device clear and trigger instructions and other management messages Do not use cmd to send programming instructions to devic
72. ake itself CIC If you passed control to some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted If you do not give an alist and the GPIB 232CT is not CIC it assumes it will be addressed by the Controller If you do not give an alist and the GPIB 232CT is CIC it addresses itself as Talker and assumes the Listeners are already addressed The first part of this programming message up to lt CR gt is buffered meaning the GPIB 232CT will not act upon it until it receives lt CR gt The string that follows the first line is piped to the GPIB non buffered This allows you to send a string larger than the GPIB 232CT s internal buffer with one programming message The GPIB 232CT aborts the GPIB write if it receives Device Clear or Selected Device Clear and its Listen Address The GPIB 232CT aborts the GPIB write and records the EABO error if at any time during the GPIB write the time limit set for I O functions expires This limit is 10 seconds unless you use tmo to change it The GPIB 232CT also aborts the wrt and records the ENOL error if there are no addressed Listeners when it begins to send data tmo for timeout information Appendix B for more error information and spign for serial port error handling information National Instruments Corp 5 61 GPIB 232CT User Manual S Mode Functions Examples 1 PRIN
73. and serial error whenever a new error occurs GPIB error and serial error are cleared only after you have requested status Refer to the following examples for ways in which to use the status information When you wish to begin continuous status reporting send the stat c s stat c n orstat c n s programming message When you call stat with both n and s modes specified the numeric status is always returned first If you call stat without an argument continuous status reporting is disabled National Instruments Corp 8 17 GPIB 232CT User Manual G Mode Functions Chapter 8 Examples 1 10 20 30 40 50 60 70 80 90 L00 10 20 L30 140 L50 L60 L70 L80 L90 200 500 510 520 530 540 10 20 30 40 50 60 70 80 90 L00 10 20 L30 REM Tell GPIB 232CT to send us numeric REM status WRT stat n CHR 13 CALL IBWRT GPIB232 WRT REM Now read the status from the REM GPIB 232CT STATUS SPACE 10 GPIBERRS SPACES 10 SPERRS SPACES 10 COUNTS SPACES 10 CALL IBRD GPIB232 STATUSS REM Read up to 10 bytes of status REM The GPIB 232CT returns 4 pieces of REM status one for each IBRD We are set REM up to terminate read on linefeed which REM is what terminates each piece of status STATUS VAL STATUSS CALL IBRD GPIB232 GPIBERRS Read GPIB error CALL IBRD GPIB232 SPERRS Read serial error CALL IBRD GPIB232 COUNTS Read count REM Call error routine
74. anel LED indicator or onscreen module responses GPIB 232CT User Manual viii National Instruments Corp lt gt Abbreviations Preface Angle brackets enclose the ASCII character symbols for certain keystrokes For example lt CR gt for carriage return and lt LF gt for linefeed The following abbreviations are units of measure that are used in the text of this manual A kbytes sec lt m M Mbytes sec mA mm oz sec V VAC VDC ampere Celsius degree greater than greater than or equal to hexadecimal hertz inch 1 024 1000 bytes per second less than less than or equal to meter 1 048 576 1 000 000 bytes per second milliampere millimeter ounce percent second volt volts alternating current volts direct current National Instruments Corp ix GPIB 232CT User Manual Preface Customer Communication We appreciate communicating with the people who use our products If you encounter any technical problems you can use the following toll free number between the hours of 8 00 a m and 5 30 p m central time to reach the National Instruments applications engineering department 512 794 0100 800 IEEE 488 toll free U S and Canada For your documentation comments we have included a User Comment Form at the back of the manual Please mail it to the address printed at the bottom of the form GPIB 232CT User Manual x National Instruments Corp Contents Chapt
75. anual Enable GPIB 232CT XON XOFF protocol for TX and RX Disable protocol on TX enable protocol on RX Return current settings transmit protocol disabled receive protocol enabled Disable protocol on RX keep current setting on TX 5 64 National Instruments Corp Chapter 6 Installation and Configuration in G Mode If you plan to operate in G mode use this chapter to install and configure the GPIB 232CT Then read Chapters 7 and 8 to learn about the programming messages Installation There are five basic steps to installing the GPIB 232CT 1 Inspect the GPIB 232CT for damage that may have been caused in shipment 2 Verify the voltage requirement 3 Configure the operating parameters 4 Connect the cables 5 Power on the unit These steps are described in more detail in the following sections Step 1 Inspection Before you install the GPIB 232CT 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 National Instruments Corp 6 1 GPIB 232CT User Manual Installation and Configuration in G Mode Chapter 6 Step 2 Verify the Voltage Requirement The GPIB 232CT is shipped from the factory with eithe
76. anual Programming in S Mode Chapter 4 Table 4 5 GPIB Initialization Functions Function CADDR address EOS modes eoschar EOT on off ONL on off RSC on off TMO values Purpose Change the IEEE 488 address of the GPIB 232CT Change or disable GPIB end of string termination mode Enable or disable END termination message on GPIB write operations Place the GPIB 232CT online offline Request System Control Change or disable time limits Table 4 6 Serial Poll Functions Function RSP address list RSV status byte GPIB 232CT User Manual Purpose Conduct request a serial poll Request service and or set or change the serial poll status byte 4 8 National Instruments Corp Chapter 4 Programming in S Mode Table 4 7 Low Level Controller Functions Function Purpose CAC mode Become Active Controller CMD count commands GTS mode Send IEEE 488 commands Go from Active Controller to Standby PCT address Pass Control SIC time Send interface clear SRE on off Set clear remote enable Table 4 8 Parallel Poll Functions Function Purpose IST on off Set or clear individual status bit for use in GPIB 232CT response to Parallel Polls PPC values Parallel Poll Configure PPU address list Parallel Poll Unconfigure RPP Conduct request a Parallel Poll National Instruments Corp 4 9 GPIB 232CT User Manual Programming in S Mode Serial Port
77. any cables that may be connected to the unit 2 Unscrew the two screws on the opposite sides 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 switch U22 on the printed wire board 5 Set the switches for the desired mode of operation Refer to the following section Set Configuration Switches Caution Most of the circuitry in the GPIB 232CT 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 GPIB 232CT User Manual 3 2 National Instruments Corp Chapter 3 Installation and Configuration in S Mode Set Configuration Switches The DIP switch at location U22 on the printed wire board is used to configure the serial port parameters of the GPIB 232CT while in S mode The DIP switch shown in Figure 3 1 has eight configuration switches ON indicates that the switch is pressed on the 12 3 4 5 6 7 8 ON side i H H H H H H H OFF indicates that the switch is pressed on the OFF side Ho ZO Figure 3 1 S Mode Switch Settings Tables 3 1 and 3 2 show the possible configurations of the eight switches and what the configurations indicate Table 3 1 Configuration Parameters for Switches 1 through 5 Position Indication
78. are chosen a full 8 bit comparison is used If B is the only mode chosen the EARG error is posted If D is chosen all EOS modes are disabled By default all EOS modes are disabled If you call eos without an argument the GPIB 232CT returns to you the current eos settings The assignment made by this function remains in effect until you call eos again you call on1 or you turn the GPIB 232CT off See Also Chapter 7 the section entitled GPIB Read and Write Data Termination and Operation of the GPIB 232CT as a Serial Device and the srqen function in this chapter Examples 1 WRTS EOS X 13 CHRS 13 Send EOI with lt CR gt CALL IBWRT GPIB232 WRTS Compare 7 bits 2 WRT e0s CHR 13 What are the CALL IBWRT GPIB232 WRTS current EOS settings CALL IBRD GPIB232 RESPS RESPS contains X 13 lt CR gt lt LF gt GPIB 232CT User Manual 8 6 National Instruments Corp Chapter 8 G Mode Functions id Identify System Type General Use function Syntax id lt CR gt Purpose You use id if you wish to know the revision level of your software or if you wish to know how much RAM is installed in your GPIB 232CT Remarks The identification is returned in three strings The first two strings identify the company product model the software revision level and a copyright notice The third string identifies the number of bytes of RAM in the GPIB 232CT Examples 1 WRTS id CHRS 13 Get system
79. ary address plus 1 with secondary addressing disabled However if you select a primary address of 30 with the configuration switch the serial device will be at address 0 The two primary addresses recognized by the GPIB 232CT are referred to as the GPIB 232CT address and the serial device address Addressing Terminology When the GPIB 232CT receives the serial device address the data it sends and receives is referred to as serial data National Instruments Corp 7 3 GPIB 232CT User Manual Programming in G Mode Chapter 7 When the GPIB 232CT receives its own address the data it receives is referred to as programming messages the data it sends is referred to as status information The GPIB 232CT and Serial Device as Listener When the GPIB 232CT receives its own listen address it examines the data received over the GPIB treats it as a programming message or messages and takes actions based on that data When the GPIB 232CT receives the serial device listen address it forwards the data received over the GPIB to the serial port without examining the data for meaning For example let s say you have a serial printer connected to the GPIB 232CT and you wish to send a data file from your computer over the GPIB to the printer Ordinarily when the printer buffer is full the printer sends the XOFF character when the printer is ready to receive more characters it sends the XON character So before you send your file to the p
80. at 500 if error occurred IF STATUS lt 0 THEN GOTO 500 REM Print GPIB error and serial error REM values to determine what errors occurred PRINT GPIB error GPIBERRS PRINT Serial error SPERRS STOP REM Turn on continuous status reporting REM in numeric format WRTS stat c n CALL IBWRT GPIB232 WRT REM If we have 3 bytes in the serial port REM buffer a typical response would be REM 262 lt CR gt lt LF gt 0 lt CR gt lt LF gt 0 lt CR gt lt LF gt 3 lt CR gt lt LF gt REM Read the GPIB 232CT status read 30 REM bytes or until EOI is received RDS SPACES 30 CALL IBRD GPIB232 RDS REM Print the status information PRINT GPIB 232CT status is RDS GPIB 232CT User Manual 8 18 National Instruments Corp Chapter 8 G Mode Functions 3 10 20 30 40 50 60 70 80 90 100 REM Turn on continuous status reporting REM in symbolic format WRTS Stat c s CALL IBWRT GPIB232 WRT REM Read the GPIB 232CT status read 50 REM bytes or until EOI is received RDS SPACES 50 CALL IBRD GPIB232 RDS REM Print the status information PRINT GPIB 232CT status is RDS Printed information is GPIB 232CT status is CMPL NGER NSER 3 National Instruments Corp 8 19 GPIB 232CT User Manual G Mode Functions Chapter 8 xon Change Serial Port XON XOFF Protocol Type Syntax Purpose Remarks Serial Port Configuration function xon booltx bo
81. comments stat c s n Enable continuous status reporting 344 0 0 3 CMPL REM ATN TACS Status returned NGER NSER 3 wrt 10 ABCDE Write the string ABCDE 296 to device 10 0 Status returned 0 5 CMPL CIC TACS NGER NSER 5 GPIB 232CT User Manual 5 52 National Instruments Corp Chapter 5 S Mode Functions tmo Change or Disable Time Limit Type Syntax Purpose Remarks Initialization function tmo timeio timesp lt CR gt You use tmo at the beginning of your program to change the time limits in effect on the GPIB 232CT The time limits prevent the GPIB 232CT from hanging indefinitely when waiting for critical events to occur The arguments timeio and timesp are numeric strings timeio specifies the amount of time in seconds the GPIB 232CT waits for an I O operation rd wrt cmd or the wait function to complete timesp specifies the amount of time in seconds each device is given in which to respond to a serial poll The power on timeouts are 10 seconds for timeio and 1 10 of a second for timesp timeio and timesp can be any decimal number between 00001 and 3600 which corresponds to time limits between 10 microseconds and 1 hour 10 1 specifies a time of 10 seconds for I O operations and 1 10 of a second for serial poll response timeio and timesp can also be 0 which disables either timeout accordingly Neither timeio nor timesp can contain commas The timeio time limi
82. cords the EARG error See Also stat and tmo Examples 1 PRINT 1 wait x5000 Wait for TIMO or SRQI INPUT 1 STATUS GPIBERR SPERR COUNT Get status info IF STATUS AND amp H4000 lt gt 0 THEN GOTO 1000 T TIMO bit is set we timed out before getting SRQI Go to an error routine at line 1000 IF STATUS AND amp H1000 lt gt 0 THEN GOTO 200 T SRQI bit set go to routine to conduct a serial poll 2 PRINT 1 wait 4 Wait indefinitely to become LACS INPUT 1 STATUS GPIBERR SPERR COUNT Get status info PRINT 1 rd 10 Now that GPIB 232CT is addressed to listen read 10 bytes from the GPIB Input 10 bytes from serial port buffer INPUT 1 CNT Input number of valid bytes in CNTS RESPS INPUTS 10 1 National Instruments Corp 5 59 GPIB 232CT User Manual S Mode Functions Chapter 5 wrt Write Data Type I O Function Syntax wrt count alist lt CR gt data lt CR gt Purpose You use wrt to send data over the GPIB Remarks The argument count is a numeric string preceded by a number sign count The string specifies a number between 1 and 65535 and must not contain a comma count specifies the number of data bytes to send The number of data bytes must not include the carriage return that indicates the end of the programming message The argument data is a string of 8 bit characters that are transferred without any t
83. ction Syntax ist bool lt CR gt Purpose You use ist when the GPIB 232CT participates in a parallel poll that is conducted by another device that is Active Controller Remarks Ifthe argument bool is 1 the GPIB 232CT s individual status bit is set to 1 If the argument bool is 0 the GPIB 232CT s individual status bit is cleared The power on default is 0 If you call ist without an argument the GPIB 232CT returns the value of its individual status bit See Also ppc and Appendix F Parallel Polling Examples 1 PRINT 1 ist 1 Set ist to 1 2 PRINT 1 IST 0 Clear ist to 0 3 PRINT 1 ist What is ist set to response 0 lt CR gt lt LF gt ist is currently 0 GPIB 232CT User Manual 5 22 National Instruments Corp Chapter 5 S Mode Functions loc Go to Local Type Syntax Purpose Remarks Bus Management function loc alist lt CR gt You use loc to put a device in local program mode In this mode you can program the device from its front panel Since a device must usually be placed in remote program mode before it can be programmed from the GPIB the GPIB 232CT automatically puts the device in remote program mode You then use loc to return devices to local program mode The argument alist is a list of addrs separated by commas or spaces addrs are device addresses that specify the GPIB addresses of the devices you wish to return to local mode A device address consists
84. d If you call echo without an argument the GPIB 232CT returns the current setting By default echoing is disabled In a debugging environment where the success of your communication with the serial device is unclear you could connect a terminal to the GPIB 232CT instead of connecting the serial device to the GPIB 232CT Now the data that the GPIB 232CT normally sends to the serial device is displayed on the terminal screen Also you can type characters on the terminal to send to the GPIB 232CT just as your serial device sends characters to the GPIB 232CT With echo enabled the GPIB 232CT echoes back to the terminal what you type so that you can verify that what the GPIB 232CT receives is exactly what you type National Instruments Corp 8 3 GPIB 232CT User Manual G Mode Functions Chapter 8 Examples 1 WRTS echo 1 CHR 13 Enable character CALL IBWRT GPIB232 WRTS echoing 2 WRTS ECHO 0 CHRS 13 Disable character CALL IBWRT GPIB232 WRTS echoing 3 WRTS echo CHR 13 What is the CALL IBWRT GPIB232 WRTS current echo CALL IBRD GPIB232 RESPS status RESPS contains 0 lt CR gt lt LF gt character echo is disabled GPIB 232CT User Manual 8 4 National Instruments Corp Chapter 8 G Mode Functions eos Change Disable GPIB EOS Termination Mode Type GPIB Configuration function Syntax eos X B eoschar lt CR gt or eos D lt CR gt Purpos
85. de Functions Chapter 5 eos Change Disable GPIB EOS Termination Mode Type Syntax Purpose Remarks REOS terminate read when EOS is detected XEOS set EOI with EOS on write functions BIN compare all 8 bits of EOS byte rather than low 7 bits all read and write functions DISABLE disable all eos modes Initialization function eos R X B eoschar lt CR gt or eos D lt CR gt You use eos at the beginning of your program if you wish to use an eos mode when you transfer data to and from the GPIB eos tells the GPIB 232CT when to stop reading information from the GPIB eos also enables the GPIB 232CT to tell other devices that it is finished writing information to the GPIB eos defines a specific character end of string EOS to be recognized as a string terminator The arguments R X B and D specify GPIB termination methods They enable or disable the corresponding eos mode If a particular letter is specified the corresponding eos mode is enabled If it is not specified the corresponding eos mode is disabled eoschar is a numeric string that represents a single ASCII character For example 10 represents the ASCII linefeed character Table 5 1 Data Transfer Termination Methods Description Letter GPIB 232CT User Manual 5 12 National Instruments Corp Chapter 5 S Mode Functions Methods R and B determine how GPIB read operations performed by the GPIB 232CT terminate If Method
86. des cccceccesceeseeseeeseeeeeeeeeeseeeeeeseeeeeeneeees B 10 Appendix C The Serial Connection ipo sciasnagtigrguaw eovaanteunian C 1 RS 232 res cssetece iil etches eee Ta EEEE A a a C 1 Interfacing the GPIB 232CT to a DCE C 3 Interfacing the GPIB 232CT to a DTE seeren C 5 Buffering and Handshaking 0 0 eessseeseeeeceeeeeeeeeeseeseeneeeees C 6 Hardware Handshake ceeseeesceseeeeeneeeeeeeeseeeseeens C 7 XON X OPE enina n aa a aias C 8 Appendix D Operation of the GPIB 0 00 00 cccccccccssesseseesesseseesesteseeseaneaes D 1 Ty p s of MESA E S e a r a a ES D 1 Talkers Listeners and Controllers GPIB 232CT User Manual xiv National Instruments Corp Contents The Controller In Charge and System Controller D 3 GPIB Signals and Linesin iieii ari aasia D 3 Data LINES aigres oreson iress ee e A G sacha OEA D 4 Handshake Lines n oncnnneonrcrein nene i D 5 NRFD not ready for data 00 0 0 eee D 5 NDAC not data accepted 0 eee eeeeeeeeeee D 5 DAV data Valid e ceeceeseeseeteeeeeeeeerees D 5 Interface Management Lines n se D 5 ATN attention 0 00 ceeeesceeeeeseeeseseeeeeeeee D 5 TFC interface clear cccecceeseeeseeeseees D 6 REN remote enable cccseeeeeseeeeeeeee D 6 SRQ Service request 0 eeeeeeeeeeeneeeteeeenes D 6 EOI end or identify 0 0 0 eeeeeeseeseeeeeee D 6 Physical and Electrical Characteristics 00 0 cceeeeseseseeeeeeeeeee
87. e You use eos to enable the GPIB 232CT to add the GPIB END message to the data string sent by the serial device when the data string contains the specified end of string character Remarks eos applies only when the GPIB 232CT has received the serial device talk address and is sending serial data to the GPIB It does not apply when the GPIB 232CT reads serial data or programming messages from the GPIB The arguments X B and D specify GPIB data transfer termination methods The argument eoschar is a numeric string representing a single ASCII character that is to be the EOS byte The arguments X and B are used to enable the corresponding EOS mode The argument D disables all EOS modes Table 8 1 Data Transfer Termination Methods Description Letter XEOS set EOI with EOS when sending data from serial device X B BIN compare all 8 bits of EOS byte rather than low 7 bits DISABLE disable all EOS modes D National Instruments Corp 8 5 GPIB 232CT User Manual G Mode Functions Chapter 8 If Methods X or X and B are chosen the GPIB 232CT automatically sends the END message along with eoschar when performing GPIB writes of serial data That is when the GPIB 232CT receives eoschar over the serial port and sends it on to the GPIB it will also assert EOI along with that byte When X alone is chosen END is sent with the EOS byte when the low seven bits of that byte match the low seven bits of eoschar When X and B
88. e control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted If you call rsp without an argument the GPIB 232CT records the EARG error tmo for timeout information National Instruments Corp 5 39 GPIB 232CT User Manual S Mode Functions Chapter 5 Example 1 PRINT 1 rsp 1 28 5 9 Poll 3 devices response 42 lt CR gt lt LF gt device 9 did not 30 lt CR gt lt LF gt respond within the 1 lt CR gt lt LF gt timeout period DIM SPR 2 Read 3 responses from FOR I 0 to 2 serial port buffer LINE INPUT 1 SPR I Store each serial poll IF SPR I 1 THEN GOSUB 1000 NEXT I Response in the array 1000 is an error routine REM Code will now interpret poll responses GPIB 232CT User Manual 5 40 National Instruments Corp Chapter 5 S Mode Functions rsv Request Service Set or Change Serial Poll Status Byte Type Syntax Purpose Remarks Examples Serial Poll function rsv spbyte lt CR gt You use rsv if the GPIB 232CT is not the GPIB Controller and you wish to request service from the Controller using the Service Request SRQ signal The GPIB 232CT will provide a user defined status byte when the Controller serially polls it The argument spbyte is a numeric string specifying the decimal value of the new GPIB 232CT serial poll response byte The serial poll response byte is the status byte the
89. e Controller function is usually handled by a computer In S mode the GPIB 232CT peforms the following three roles e Controller to manage the GPIB e Talker to send data to an attached GPIB device e Listener to receive data from an attached GPIB device In G mode the GPIB 232CT is a GPIB device It performs only the following two roles e Talker to send data to the GPIB host e Listener to receive data from the GPIB host GPIB 232CT User Manual D 2 National Instruments Corp Appendix D Operation of the GPIB The Controller In Charge and System Controller Although there can be multiple Controllers on the GPIB only one Controller at a time is active or Controller In Charge CIC Active control can be passed from the current CIC to an idle Controller Only one device on the bus the System Controller can make itself the CIC The GPIB interface board is usually the System Controller in S mode and is never the System Controller in G mode GPIB Signals and Lines The interface system consists of 16 signal lines and 8 ground return or shield drain lines The 16 signal lines are divided into the following three groups e Eight data lines e Three handshake lines e Five interface management lines National Instruments Corp D 3 GPIB 232CT User Manual Operation of the GPIB Appendix D Figure D 1 shows the arrangement of these signals on the GPIB cable connector a suffix indicates that the signal is active low
90. e GPIB 232CT Chapter 1 The LEDs show the current status of the GPIB 232CT at all times Table 1 4 describes each LED LISTEN Table 1 4 LED Descriptions Indication Indicates that power to the unit has been applied and the ON OFF switch is in the ON position Indicates that the power on self test has passed successfully and the unit is ready to operate Indicates that the GPIB 232CT is configured as a GPIB Talker Indicates that the GPIB 232CT is configured as a GPIB Listener Indicates that the GPIB signal line SRQ is asserted low Indicates that the GPIB signal line ATN is asserted low Note indicates that the signal is active low negative logic GPIB 232CT User Manual 1 6 National Instruments Corp Chapter 1 Description of the GPIB 232CT The GPIB 232CT Rear Panel The rear panel of the GPIB 232CT is shown in Figure 1 3 The power cable RS 232 cable and GPIB cable are shown connected to the rear panel of the GPIB 232CT Figure 1 3 The GPIB 232CT Rear Panel National Instruments Corp 1 7 GPIB 232CT User Manual Description of the GPIB 232CT Chapter 1 The RS 232 Port The RS 232 port on the GPIB 232CT 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
91. e 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 National Instruments Corp 6 7 GPIB 232CT User Manual Chapter 7 Programming in G Mode This chapter shows how to program the GPIB 232CT in G mode using programming messages It describes programming messages their format and how they are processed along with the functions and function arguments that make up the programming messages This chapter also explains how to communicate with your serial device through the GPIB 232CT Programming Messages You program the GPIB 232CT by sending it programming messages which are ASCII strings by way of its GPIB port Programming Message Format The programming message consists of a function name one or more arguments optional followed by a carriage return lt CR gt or a linefeed lt LF gt or a carriage return followed by a linefeed lt CR gt lt LF gt Carriage return and linefeed can be expressed in BASIC as CHRS 13 and CHRS 10 respectively Example of a Programming Message In the following lines of BASIC code WRTS eos x 10 CHRS 13 CALL IBWRT GPIB232 WRTS WRTS contains the programming message in which eos is the function name x and 10 are the arguments and CHR 13 is the terminating carriage
92. e been caused in shipment 2 Verify the voltage requirement 3 Configure the operating parameters 4 Connect the cables 5 Power on the unit These steps are described in more detail in the following sections Step 1 Inspection Before you install the GPIB 232CT 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 for reshipment If the equipment appears to be damaged do not attempt to operate it Contact National Instruments for instructions National Instruments Corp 3 1 GPIB 232CT User Manual Installation and Configuration in S Mode Chapter 3 Step 2 Verify the Voltage Requirement The GPIB 232CT 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 Caution Operating the unit at any voltage other than the one specified could damage the unit Step 3 Configure the Operating Parameters The GPIB 232CT is shipped from the factory configured to operate in S mode The serial port is configured at 9600 baud 1 stop bit no parity and 7 data bits If you wish to change any of the GPIB 232CT 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
93. e from the plotter To communicate with the GPIB 232CT send it data strings using the IBWRT function The following steps explain each of the strings sent to the GPIB 232CT Programming Steps Step 1 stat Function Send stat c nif you want status information returned after each programming message Next use the ibrd function to read back status after this string is sent Step 2 GPIB Initialization Functions If there are GPIB functions on the GPIB 232CT you wish to change from their default settings send strings to the GPIB 232CT at this time No changes are necessary to communicate with this plotter Step 3 Serial Port Initialization Functions Change any serial port initialization functions if necessary This plotter sends and receives 7 bit data Since the default of the GPIB 232CT is 8 bit data send the string spset 7 to change to 7 bit data transfers Read status after the string has been sent GPIB 232CT User Manual H 12 National Instruments Corp Appendix H Sample Programs Step 4 Communicate with Plotter Before communicating with the plotter send the initialization strings to the GPIB 232CT Next send strings to the plotter the GPIB 232CT does not interpret these strings but sends them straight to the plotter Remember to read status after you send a programming message to the GPIB 232CT 10 G232CTS GPIB232CT 20 CALL IBFIND G232CTS GPIB232CT 25 Open GPIB 232cT 30 SDNAMES PLOTTER 40 CALL
94. e information you are entering the echo function must be enabled In this case a serial port initialization message is sent before stat To enable echo type the following GPIB 232CT User Manual H 2 National Instruments Corp Appendix H Sample Programs echo 1 lt CR gt As you type the characters will not be echoed yet You are enabling echo for future programming messages Remember to type a carriage return Programming Steps Step 1 stat Function When using the stat function use stat c s so the GPIB 232CT will report status after each programming message Instat c s the c stands for continuous and the s stands for symbolic Because you are using a terminal it is easier to interpret the status report if it is returned in symbolic form Type the following stat c s lt CR gt The status displays on the terminal s screen immediately The status should look something like this CMPL NGER NSER 0 This status report shows the status after the previous programming message It also shows that echo 1 was a previous programming message because characters you enter are now being echoed This status reports CMPL and no errors Step 2 Serial Port Functions Determine what serial port functions are needed to change default settings echo was enabled as a preliminary step No other changes are necessary for this GPIB plotter National Instruments Corp H 3 GPIB 232CT User Manual Sample Programs Appendix H Step 3
95. eeeeseeeneeaes 5 42 spign Ignore Serial Port Errors 00 0 0 cceeeeeesseeseeseeeeeneeeeeeeeeeees 5 44 sre Set or clear Remote Enable ccccceesesseesesneeeeesneeeees 5 46 stat Return GPIB 232CT Status cee ceeseeeseeseeeeseeeeseeeenees 5 47 tmo Change or Disable Time Limit eee eeeeeeeeeeeeeeeees 5 53 trg Trigger Selected Device S 0 ce eeeeeseeesceseetecseeteeterneeneesees 5 55 GPIB 232CT User Manual xii National Instruments Corp Contents wait Wait for Selected Event 0 0 ei eceseeseeseeseeseeterseseeeeeesees 5 57 Writ Write Data c cecssssscasscisessesseetssedecevatestansseescaesssestiaghoesegecass 5 60 xon Change Serial Port XON XOFF Protocol 5 63 Chapter 6 Installation and Configuration in G Mode 0 6 1 Tnistallatonis ea ec celetag dene eee ven EE RARS 6 1 Step 1 Inspection iieii eorias iire esasa 6 1 Step 2 Verify the Voltage Requirement 6 2 Step 3 Configure the Operating Parameters 6 2 Set Configuration Switches ccc eee 6 3 Example Settings for Configuration SWICK ipti denies 6 6 Step 4 Connect the Cables ee eeeeeeeeeeeeeee 6 6 Step 5 Power on the Unit 6 7 Chapter 7 Programming in G Mode 0 0 0 0 cccecseeseeseestesseeseeeeseeeeseeneeneeees 7 1 Programming Messages ccsscessceeseeeeeeeeceseeeseeeeeeeeeeseeesrensees 7 1 Programming Message Format 7 1 Example of a Programming Message 7
96. epresents a single GPIB error condition present serial error represents a single serial error condition present count is the number of bytes currently contained in the GPIB 232CT s serial port receive buffer Table 8 3 GPIB 232CT Status Conditions Numeric Symbolic Value n Value s Description Error detected 16384 Reserved Reserved 4096 Reserved Reserved Reserved 8 Reserved 3 continues National Instruments Corp 8 15 GPIB 232CT User Manual G Mode Functions Chapter 8 Table 8 3 GPIB 232CT Status Conditions continued Numeric Symbolic Value n Value s Description Bit 2 4 Reserved 2 Reserved 1 1 Reserved 0 Table 8 4 GPIB Error Conditions Numeric Symbolic Value n Value s Description 7 10 Reserved 17 ECMD Unrecognized command GPIB 232CT User Manual 8 16 National Instruments Corp Chapter 8 G Mode Functions Table 8 5 Serial Error Conditions Numeric Symbolic Value n Value s Description 0 NSER No serial port error condition to report 1 EPAR Serial port parity error 2 EORN Serial port overrun error 3 EOFL Serial port receive buffer overflow 4 EFRM Serial port framing error A detailed description of the conditions under which each bit in status is set or cleared can be found in Appendix B The GPIB 232CT updates status and count at the end of each programming message It updates GPIB error
97. er 1 Description of the GPIB 232CT oo teeteeteeeeees 1 1 IntrOductoniss i ihssesiecishehci hl St aed ahha ately 1 1 What Your Kit Contains 0 eee ceeseeeecseeeseeeceeeesesseeseeeeeeeees 1 2 Optional Equipment ccc eeesesceseeeeseeeceeeeteecseseeeeseeaeeaees 1 3 GPIB 232CT Specifications ceeecessesseeseesecneeeeceeceeeeesseeeeees 1 4 The GPIB 232CT Front Panel eee eeeeeeeseeeeceeeeeeeeeeeeees 1 5 The GPIB 232CT Rear Panel eee eessesseeseeseeecteeeesseeeeeeees 1 7 TheRS 232 Porti snne nanninta aii dea 1 8 The GPIB Poit eoeta ooreo Rea a E teal 1 9 Chapter 2 The GPIB 232CT Modes of Operations cu emloa doe oleae 2 1 Introductions cni oian nin e e aa R REES 2 1 Choosing Between S Mode or G Mode sssssseeeseeeeereerrererereeeees 2 1 Chapter 3 Installation and Configuration in S Mode 0 0 0 cccecccccesceseeseseeseseeseeseeseeeeenenees 3 1 TnistallatiOn o erea e oe E EE A E E ese eee ees 3 1 Step 1 Inspection s ssisesi inonsan iii 3 1 Step 2 Verify the Voltage Requirement 3 2 Step 3 Configure the Operating Parameters 3 2 Set Configuration Switches sees 3 3 Default Settings for Configuration Switch 3 4 Step 4 Connect the Cables ee eeeeeeeeeeeeeee 3 5 Step 5 Power on the Unit 3 5 Chapter 4 Programming in S Mode 0 cccccsceseeseeeeseeseeeeeseeseesesseeneeees 4 1 Programming Messages cesccescesseeeseeeeceseeeseeeeeeeeeeneeeteensees 4 1 Pr
98. er the brackets as part of your argument e Terminate each programming message with a carriage return lt CR gt a linefeed lt LF gt or a carriage return followed by a linefeed lt CR gt lt LF gt The terminator is denoted by a lt CR gt in the syntax portions of the function descriptions In the programming examples the BASIC PRINT statement automatically sends a carriage return at the end of the string so a carriage return is not placed there explicitly To send more than one programming message per PRINT statement embed a lt CR gt denoted by CHR 13 or a lt LF gt denoted by CHRS 10 in the statement For example to send the two programming messages send interface clear SIC and send remote enable SRE you could use either of these two sequences PRINT 1 sic PRINT 1 sre 1 or PRINT 1 Sic CHRS 13 sre 1 e For all examples the communications port has been assigned to file number 1 1 by the BASIC OPEN COM statement National Instruments Corp 5 1 GPIB 232CT User Manual S Mode Functions Chapter 5 e The I O and bus management functions should meet most of your needs In the descriptions that follow these functions are marked with an asterisk These are the most frequently used functions e Itis only necessary for you to send enough characters of the function name to distinguish it from other functions Those characters are shown in boldface in the syntax porti
99. er to parallel poll it GPIB 232CT User Manual F 2 National Instruments Corp Appendix F Parallel Polling The Parallel Poll In the S Mode after configuring the device the GPIB 232CT now conducts a parallel poll by calling rpp In the previous example where the device was sent a configuration byte of hex 6A if the device s IST bit matches the S bit of hex 6A rpp will return the value 04 Here the third least significant bit is set corresponding to DIO line 3 If any other devices responded positively on other lines those corresponding bits would be set as well Note The Controller can configure more than one device to respond on the same data line in which case the bits in the response byte are set by the ORing of all the responses on that line In the G Mode the GPIB 232CT sets its IST bit whenever it asserts SRQ and clears it whenever it unasserts SRQ Refer to Chapter 7 for the conditions under which the GPIB 232CT asserts SRQ If the Active Controller has sent it the Parallel Poll Configure byte hex 6D binary 0110 1101 and parallel polls it while its IST bit is set it responds by asserting data line 6 If the Active Controller sent it the parallel poll configure byte hex 65 binary 0110 0101 and parallel polls it while its IST bit is set it responds by not asserting data line 6 Disabling Parallel Poll Response The Active Controller can disable a specific device from responding to a parallel poll by calling ppu
100. es Use rd and wrt to send or receive device programming instructions and other device dependent information GPIB 232CT User Manual 5 8 National Instruments Corp Chapter 5 See Also S Mode Functions The cmd operation terminates when e The GPIB 232CT successfully transfers all commands e The GPIB 232CT detects an error GPIB 232CT is not CIC e The I O time limit is exceeded e The Take Control TCT command is in your command string and is sent to the GPIB e The Interface Clear IFC message is received from the System Controller not the GPIB 232CT After cmd terminates the GPIB 232CT records the number of command bytes it actually sent If one of the events described above occurs the count may be less than expected If you specify count and enter more than count command bytes the excess command bytes up to the lt CR gt lt LF gt are discarded If you call cmd and the GPIB 232CT is not CIC the GPIB 232CT records the ECIC error If the GPIB 232CT is CIC but not Active Controller it takes control and asserts ATN before sending the command bytes It remains Active Controller afterward Appendix A to convert hex values to ASCII characters National Instruments Corp 5 9 GPIB 232CT User Manual S Mode Functions Examples 1 PRINT 1 CMD PRINT 1 PRINT 1 WRT PRINT 1 ABCDE 2 PRINT GPIB 232CT User Manual Program Chapter 5 device at addre
101. fore communicating with the printer send the initialization strings to the GPIB 232CT Next send strings to the printer the GPIB 232CT does not interpret these strings but sends them straight to the printer 10 G232CTS GPIB232CT 20 CALL IBFIND G232CTS GPIB232CT 25 Open GPIB 232CT 30 SDNAMES PRINTER 40 CALL IBFIND SDNAMES PRINTERS Open PRINTER 50 WRTS stat c n CHRS 13 60 CALL IBWRT GPIB232CT WRTS 65 Enable continuous status reporting 70 RDS SPACES 25 80 CALL IBRD GPIB232CT RDS 90 Read up to 25 bytes of status information 100 IF ASC RDS lt gt CHRS 45 THEN GOTO 310 110 If first characterin RDS is a minus sign National Instruments Corp H 15 GPIB 232CT User Manual Sample Programs Appendix H 120 210 220 230 300 310 320 330 then go to error function WRTS Hello world CHR 13 CALL IBWRT PRINTER WRTS Send string to printer STOP PRINT An error occurred PRINT Status GPIB error serial error count RD END GPIB 232CT User Manual H 16 National Instruments Corp User Comment Form National Instruments encourages you to give us your comments on the documentation supplied with its products This information helps us provide quality products to meet your needs Title GPIB 232CT User Manual Edition Date July 1992 Part Number 320114 01 Please comment on the completeness clarity and organization
102. gn at the beginning of your program if you wish to change the effect that serial port errors have on how the GPIB 232CT processes programming messages and data This function tells the GPIB 232CT to ignore or not to ignore the occurrence of serial port errors By default the GPIB 232CT ignores serial port errors If the argument bool is 0 the GPIB 232CT will not ignore serial port errors When bool is 0 the GPIB 232CT does not execute programming messages that contain serial port errors A list of serial port errors are given in Appendix B Also if a serial port error occurs with any byte contained in a cmd or wrt data string the GPIB 232CT discards that data byte and all remaining bytes in the string The serial port errors include parity overrun framing and overflow errors If the argument bool is 1 the GPIB 232CT executes all programming messages and sends all data even if serial port errors occur as the messages and data bytes are received If you call spign without an argument the GPIB 232CT returns to you the current setting cmd and wrt GPIB 232CT User Manual 5 44 National Instruments Corp Chapter 5 S Mode Functions Examples 1 PRINT 1 spign 0 Do not execute programming messages or process data that contain serial port errors 2 PRINT 1 spign 1 Execute all programming messages and send all data even if serial port errors occur National Instruments Corp 5 45 GPIB
103. gure the GPIB 232CT The GPIB 232CT functions are divided into three groups GPIB Configuration functions Serial Port Configuration functions and General Use functions GPIB Configuration Functions Table 7 3 GPIB Configuration Functions Function Purpose eos modes eoschar Change or disable GPIB end of string termination mode srqen mask Set conditions for asserting SRQ GPIB 610 User Manual 7 8 National Instruments Corp Chapter 7 Programming in G Mode Serial Port Configuration Functions Table 7 4 Serial Port Configuration Functions Function Purpose echo on off spset modes xon modes Echo characters received from serial port Change serial port parameters Change serial port XON XOFF protocol spign on off Ignore serial port errors General Use Functions Table 7 5 General Use Functions Function Purpose id onl on off Identify system Place the GPIB 232CT online offline stat options Return GPIB 232CT status National Instruments Corp 7 9 GPIB 232CT User Manual Programming in G Mode Chapter 7 List of G Mode Functions in Alphabetical Order Table 7 6 is an alphabetical list of G mode functions Table 7 6 GPIB 232CT Functions Function Purpose echo on off eos modes eoschar Echo characters received from serial port Change or disable GPIB end of string termination mode id Identify system Place the GPIB 232CT online offline
104. he GPIB errors in detail NGER ECIC S G 0 The GPIB 232CT reports this error when GPIB 232CT detected no GPIB errors as a result of the last operation S 1 The GPIB 232CT records this error when you call a function that requires that the GPIB 232CT be CIC and it is not CIC In cases when the GPIB 232CT should always be the Controller In Charge the remedy is to be sure to call sic to send Interface Clear before attempting any of these calls and to avoid sending the command byte TCT hex 09 Take Control In multiple Controller In Charge situations the remedy is to always be certain that the CIC bit appears in status before attempting these calls If it is not you can call wait CIC to delay further processing until control is passed to the GPIB 232CT GPIB 232CT User Manual B 6 National Instruments Corp Appendix B ENOL EADR Status Information S 2 The most common cause of this error is that the GPIB 232CT attempted to write to the GPIB when no Listeners were addressed The remedy is to be sure that the proper listen address is in the alist argument string to use cmd to properly address the Listeners or to be sure some other controller has addressed the Listeners before you call wrt This error may occur more rarely in situations in which the GPIB 232CT is not the Controller In Charge and the Controller asserts ATN before the write call in progress has ended The remedy is either to reduce the write by
105. hown in Figure 6 1 has eight configuration switches ON indicates that the switch is pressed on the e e EE E ON side NI iy i H H H H H OFF indicates that the F switch is pressed on the OFF side Figure 6 1 G Mode Switch Settings Notice that to put the GPIB 232CT into G mode Switch 1 of U22 should be ON and Switches 2 and 3 should be in the OFF position Connecting the serial device to the GPIB 232CT converts the serial device into a GPIB device Each GPIB device has a GPIB address The GPIB 232CT uses two GPIB addresses the one you select by setting the configuration switches and the second address equal to the address you select plus one The first becomes the GPIB 232CT s address The second becomes the serial device s address The GPIB addresses of the GPIB 232CT and the serial device must be different from the addresses of the other GPIB devices in your system Determine the GPIB addresses of the other GPIB devices then using the list on the following page select two consecutive addresses that are not already in use Configure the GPIB 232CT primary address by setting the switches as shown in Table 6 1 The corresponding talk and listen addresses are also shown National Instruments Corp 6 3 GPIB 232CT User Manual Installation and Configuration in G Mode Chapter 6 Table 6 1 Primary Address Configurations Listen Talk Switches Primary Address Address 4 5 6 7 8 Address Dec ASCII Dec ASCII OFF
106. iittcctestaa del ghelavtceienias thontaster intestate 7 12 PPPS BOL E E EE E 7 12 LOCali A eeu tenia sae E E ANRA 7 12 Controlar i A E E EAR E 7 12 Device Clear srei ran n aa E 7 13 Chapter 8 G Mode Functions 20 00 0000 ecseeceessesseeseeseesseeseesneeseesnecseeneenneeseenees 8 1 Points to Remember seinere esn i 8 1 echo Echo Characters Received from Serial Port 6 8 3 eos Change Disable GPIB EOS Termination Mode 8 5 id Identify Syste snaren nsiet erase iiih 8 7 onl Place the GPIB 232CT Online Offline eeeeeereee 8 8 spign Ignore Serial Port Errors 0 0 0 0 sceeeeeceeceeeeseeneeeeeeeeeees 8 9 spset Change Serial Port Parameters 0 eeeeeeeeeeeseeeeeeee 8 10 srgen Enable Disable Setting of SRQ occ eeeeeseereereeteeeees 8 12 stat Return GPIB 232CT Status ee eeeceesecsneeeseeceseeeeeeeeses 8 14 xon Change Serial Port XON XOFF Protocol ceeeeeees 8 20 Appendix A Multiline Interface Messages 0 ccccccceeseseessesseeeseeneeees A 1 Multiline Interface Messages ccscceeseesseeseeeseeeeeeeeeeseeeseeesees A 2 Interface Message Reference List s ssssesssesssrseesersseseeseseeses A 4 Appendix B Status Information 2 0 0 0 ccc cscs ss essescseseeseseseseeeeseseeees B 1 Status Bits essere teistvnitedt sist er Baa ealend ate arated B 1 GPIB Error Codes ci cccsecessecsccesscscectetdcvccpsvbieeveatsscceessteerctsaveceenss B 6 Serial Port Error Co
107. ine offline continues 4 1 GPIB 232CT User Manual Programming in S Mode Chapter 4 Table 4 11 GPIB 232CT Functions continued Function Purpose PCT address PPC values Pass Control Parallel Poll Configure PPU address list RD count address Parallel Poll Unconfigure Read data RPP RSC on off RSP address list Conduct request a Parallel Poll Request System Control Conduct request a serial poll RSV status byte Request service and or set or change the serial poll status byte SIC time Send interface clear SPIGN on off Ignore serial port errors SRE on off Set remote enable STAT modes TMO values Return GPIB 232CT status Change or disable time limits TRG address list Trigger selected device s WAIT mask WRT count address list data XON modes GPIB 232CT User Manual Wait for selected event s Write data Change serial port XON XOFF protocol 4 12 National Instruments Corp Chapter 5 S Mode Functions This chapter contains descriptions of S mode functions that you use to program the GPIB 232CT These functions are in alphabetical order and are formatted to provide you an easily usable reference Points to Remember e The programming examples for each function description are in Microsoft BASIC Version 3 0 e In the syntax portion of the function descriptions arguments enclosed in square brackets are optional Do not ent
108. ion 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 malfunctions 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 book may not be copied photocopied reproduced or translated in whole or in part without the prior written consent of National Instruments Corporation Trademarks MicroGPIB is a trademark of National Instruments Corporation Product names listed are trademarks of their respective manufacturers Company names listed are trademarks or trade names of their respective companies 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 1 the limits for a Class A computing device in accordance with the specifications in Subpart J of Part 15 of U S Federal Communications Commission FCC Rules and 2 the limits for r
109. ion of each G mode function The functions are arranged in alphabetical order and each contains the syntax purpose and examples National Instruments Corp vil GPIB 232CT User Manual Preface Appendix A Multiline Interface Messages contains an ASCII chart and a list of the corresponding GPIB messages Appendix B Status Information contains explanations of status bits GPIB error codes and serial port error codes Appendix C The Serial Connection explains the RS 232 serial standard and contains information for building a serial cable Appendix D Operation of the GPIB describes the operation of the GPIB Appendix E Common Questions provides answers to common questions that frequently arise Appendix F Parallel Polling explains the use and operation of Parallel Polls Appendix G Setting Switches gives additional details about setting switches on the GPIB 232CT Appendix H Sample Programs provides some S mode and G mode sample programs Conventions Used in This Manual Throughout this manual the following conventions are used to distinguish elements of text 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 boldface Bold text in this manual denotes a signal name a front p
110. is shown in Figure 1 4 For more information on the RS 232 signals refer to Appendix C The Serial Connection Figure 1 4 The RS 232 Connector and Signal Designations GPIB 232CT User Manual 1 8 National Instruments Corp Chapter 1 Description of the GPIB 232CT The GPIB Port 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 DIOS DIOG DIO7 DIO8 REN GND TW PAIR W DAV 18 GND TW PAIR W NRFD 8 20 GND TW PAIR W NDAC GND TW PAIR W IFC GND TW PAIR W SRQ GND TW PAIR W ATN SIGNAL GROUND Figure 1 5 The GPIB Connector and Signal Designations National Instruments Corp 1 9 GPIB 232CT User Manual Chapter 2 The GPIB 232CT Modes of Operation Introduction The GPIB 232CT is capable of operating in one of two modes S mode or G mode This chapter helps you determine the mode you will use and the chapters of the manual that apply to that mode Choosing Between S Mode or G Mode You will be connecting the GPIB 232CT to both a serial device and a GPIB device The GPIB 232CT s mode of operation is determined by the role the serial device plays in your setup Is the serial device a Controller Is it going to manage the GPIB address devices and perform other GPIB Controller functions If
111. is wired straight across GPIB 232CT pin 2 to DCE pin 2 pin 3 to pin 3 and so forth Wired in this manner the GPIB 232CT can then interact to function properly handshake Figure C 1 shows a properly configured DTE to DCE cable Figure C 1 DTE to DCE Cable Configuration National Instruments Corp C 3 GPIB 232CT User Manual The Serial Connection Appendix C If your serial device does not use the same hardware handshaking protocol as the GPIB 232CT 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 232CT hardware handshaking protocol Figure C 2 shows the connections for a minimum configuration cable The GPIB 232CT connector is on the left Figure C 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 232CT User Manual C 4 National Instruments Corp Appendix C The Serial Connection Interfacing the GPIB 232CT to a DTE For serial devices set up as DTEs you must wire a DTE to DTE interface cable commonly called a null modem cable The cable must fool the GPIB 232CT into thinking it is communicating with a DCE Figure C 3 shows a null modem cable The GPIB 232CT connector is on the left Figure C 3 Null Modem Cable Configuration National Instruments Corp C 5 GPIB 232CT User
112. ite to the device at primary address 2 IN CI is the data string that contains the data wrt will send out on the GPIB In this case a lt CR gt is automatically sent by BASIC following each print string so again it is not necessary to include it here The cmd and wrt programming messages are followed by a data string that can contain 7 or 8 bit data How Messages are Processed The GPIB 232CT processes a programming message on a line by line basis The GPIB 232CT buffers the entire message interprets the function name and arguments then executes the message The data portions of the wrt and cmd functions are not processed on a line by line basis The data immediately following a wrt and a cmd are sent directly to the GPIB The GPIB 232CT recognizes lt CTRL gt h hex 8 in a programming message as a backspace and erases the previous character The GPIB 232CT recognizes lt CTRL gt h in a data string as a data byte and does not erase the previous character Function Names The function names have been selected to indicate each function s purpose thereby making your programs easy to understand However if you wish to reduce some overhead in your program and do not mind giving up these advantages you can use only as much of the function name as is necessary to distinguish it from other functions This abbreviated form of the function GPIB 232CT User Manual 4 2 National Instruments Corp Chapter 4 Programming in S M
113. ith a utility program In Applesoft BASIC there is no need to use the OPEN statement to open the serial port for communications You direct output to the serial port with the statement PR 1 and direct input to the serial port with the statement IN 1 A lt CTRL gt D CHRS 4 must be sent before each of these commands Refer to your Applesoft manual for more information Getting Ready to Program Before you start programming determine what serial port settings you require The default settings for the GPIB 232CT as given below are fine for this application e baud rate 9600 e parity none e databits 8 e stop bits 1 tT Figure H 3 S mode 8 data bits 1 stop bit no parity 9600 baud Connect the serial cable to the serial port of your computer and to the GPIB 232CT Power on the GPIB 232CT GPIB 232CT User Manual H 8 National Instruments Corp Appendix H Sample Programs Programming Steps Step 1 stat Function In Applesoft BASIC you must redirect input and output to the serial port before attempting to communicate with the GPIB 232CT Place the following statements at the beginning of your program D CHR 4 PRINT DS PR 1 PRINT DS IN 1 Step 2 Serial Port Functions Send serial port initialization programming messages if necessary For this example this step is not necessary Step 3 GPIB Initialization Functions Send GPIB initialization programming messages if necessary For this exam
114. k 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 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 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 NATIONAL INSTRUMENTS 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 act
115. ker drives it when sending data messages The way in which NRFD and NDAC are used by the receiving device is called the Acceptor Handshake Likewise the sending device uses DAV in the Source Handshake Interface Management Lines Five lines are used to manage the flow of information across the interface ATN attention The Controller drives ATN true when it uses the data lines to send commands and false when it allows a Talker to send data messages National Instruments Corp D 5 GPIB 232CT User Manual Operation of the GPIB Appendix D IFC interface clear The System Controller drives the IFC line to initialize the bus and become Controller In Charge REN remote enable The System Controller drives the REN line which is used to place devices in remote or local program mode SRQ service request Any device can drive the SRQ line to asynchronously request service from the Active Controller with the SRQ line EOI end or identify The EOI line has two purposes The Talker uses the EOI line to mark the end of a message string The Controller uses the EOI line to tell devices to identify their response in a parallel poll Physical and Electrical Characteristics Devices are usually connected with a cable assembly consisting of a shielded 24 conductor cable with both a plug and receptacle connector at each end This design allows devices to be linked in either a linear or a star configuration or a c
116. l 5 54 National Instruments Corp Chapter 5 S Mode Functions trg Trigger Selected Device s Type Syntax Purpose Remarks Bus Management function trg alist lt CR gt You use trg to trigger the specified devices The instructions for each GPIB device explain when you should trigger them and what effect the trigger has The argument alist isa list of addrs separated by commas or spaces addrs are device addresses that specify the GPIB addresses you wish to trigger A device address consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary addresses Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 32 98 or 0 x62 If you call trg without an argument the EARG error is posted If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable If you passed control to
117. l port initialization functions if you need to change default serial port settings 3 Send GPIB initialization functions if you need to change default GPIB settings 4 Communicate with the device using the rd and wrt functions and check status if you requested it After you initialize the GPIB 232CT the rd and wrt functions may be the only functions you will need National Instruments Corp H 1 GPIB 232CT User Manual Sample Programs Appendix H Using an HP 7475A Plotter with a Terminal This program is a sequence of programming messages and data strings entered from a terminal to draw a circle using an HP 7475A Color Plotter Getting Ready to Program Before you start programming determine the serial port settings you need by looking at the settings of your terminal then set the configuration switches on the GPIB 232CT so that they match the terminal characteristics Figure H 1 shows how to configure the GPIB 232CT if your terminal has the following characteristics e baud rate 19200 e parity none e databits 8 e stop bits 1 PE Figure H 1 S mode 8 data bits 1 stop bit no parity 19200 baud Next connect the serial cable to the serial port of the terminal and to the GPIB 232CT Connect the GPIB cable to the GPIB port on your device and to the GPIB 232CT Power on the GPIB 232CT A program written from a terminal does not exactly follow the steps used for most programs To be able to see on the screen th
118. ments Corp Chapter 5 Examples 1 PRINT 1 caddr 0 22 2 PRINT 1 CADDR 1 3 PRINT 1 CADDR response 1 lt CR gt lt LF gt National Instruments Corp 5 5 S Mode Functions Give GPIB 232CT a primary address of 0 and a secondary address of 22 Change GPIB 232CT primary address to 1 and disable secondary addressing Return current GPIB 232CT address GPIB 232CT User Manual S Mode Functions Chapter 5 clr Clear Specified Device Type Syntax Purpose Remarks Bus Management function clr alist lt CR gt You use clr to reset the internal or device functions of the specified devices For example a multimeter might require that you send it either the GPIB Device Clear or Selected Device Clear command to change its function range and trigger mode back to its default setting Use clr to do this The argument alist isa list of addrs separated by commas or spaces addrs are device addresses that specify the GPIB addresses you wish to clear A device address consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary address Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples
119. ments Corp Chapter 5 S Mode Functions stat Return GPIB 232CT Status Type Syntax Purpose Remarks General Use function stat c n lt CR gt or stat c s lt CR gt or stat c n s lt CR gt You use stat to obtain the status of the GPIB 232CT to see if certain conditions are currently present You use stat most often to see if the previous operation resulted in an error You should use stat frequently in the early stages of your program development when your device s responses are likely to be unpredictable The GPIB 232CT responds with status information in a form depending on the mode or combination of modes you chose n indicates that the status information will be returned as numeric strings s indicates that the status information will be returned in symbolic format that is as mnemonic strings c specifies that the status will be returned after each programming message eliminating the need to call stat after each programming message Normally you use s only when you are debugging your code and you want to print the mnemonic for each piece of status information The status information returned by the GPIB 232CT contains four pieces of information the GPIB 232CT status a GPIB error code a serial error code and a count The GPIB 232CT returns a lt CR gt lt LF gt following each piece of the response Status represents a combination of GPIB 232CT conditions Internally in the GPIB 232CT statu
120. more bytes to the GPIB 232CT by asking the GPIB 232CT to send you status information Do this by sending the GPIB 232CT its listen address and the programming message stat n Then send the GPIB 232CT its talk address and perform a GPIB read of 20 bytes The GPIB 232CT sends you its status information terminated by the GPIB END message This status information contains the number of bytes remaining in the serial port receive buffer This information will help you decide how much data to continue to collect from the serial device If the GPIB 232CT receives its talk address but has nothing to send it will respond to GPIB reads with a carriage return and a linefeed accompanied by END If the GPIB 232CT receives the serial device talk address but has no data in its serial port receive buffer to send it will wait for data from the serial device to fill the request The TALK LED on the GPIB 232CT s front panel is lit when either the GPIB 232CT is addressed to talk or the serial device is addressed to talk National Instruments Corp 7 5 GPIB 232CT User Manual Programming in G Mode Chapter 7 GPIB Read and Write Termination END and EOS You program the GPIB 232CT and the serial device to Talk in order to send status information and serial data over the GPIB You program the GPIB 232CT and the serial device to Listen in order to receive programming messages and serial data from the GPIB The IEEE 488 specification defines two ways that
121. n a GPIB error occurs that is EARG ECMD or ECAP as reported by stat National Instruments Corp 7 11 GPIB 232CT User Manual Programming in G Mode Chapter 7 e When a serial error occurs that is EPAR EORN or EFRM as reported by stat e When the serial device is not addressed as a Talker and any byte is received from the serial device or the EOS byte is received from the serial device Note You must use the srqen function to enable the GPIB 232CT to assert SRQ under the conditions listed above Parallel Poll The GPIB 232CT responds to a parallel poll by driving the line indicated by the PPE command true if the value of its individual status bit matches the sense bit of the PPE command and false otherwise Trigger This has no effect on the GPIB 232CT Local This has no effect on the GPIB 232CT Control In G mode the GPIB 232CT can act only as a Talker Listener It does not make sense for the GPIB 232CT to be passed control since all programming instructions must be sent to it from another GPIB device However the GPIB circuitry in the GPIB 232CT will allow it to be passed control in which case the GPIB 232CT will immediately assert ATN This is an error condition that can lock up your system and should therefore be avoided GPIB 610 User Manual 7 12 National Instruments Corp Chapter 7 Programming in G Mode Device Clear When the GPIB 232CT receives the universal Device Clear DCL command or whe
122. n error that corrupts the argument portion of the programming message or that corrupts the lt CR gt or lt LF gt that terminates the programming message Use stat and check serial error to determine if a transmission error has occurred S 5 The GPIB 232CT records this error when sic or sre is called when the GPIB 232CT does not have System Controller capability The remedy is to give the GPIB 232CT that capability by calling rsc At power on the GPIB 232CT assumes itself to be the System Controller GPIB 232CT User Manual B 8 National Instruments Corp Appendix B EABO ECAP ECMD Status Information S 6 The GPIB 232CT records this error when I O has been cancelled By far the most common cause of this error is a timeout condition To remedy a timeout error if I O is actually progressing but times out anyway lengthen the timeout period with tmo More frequently however the I O is stuck the Listener is not continuing to handshake or the Talker has stopped talking or the byte count in the call that timed out was more than the other device was expecting Be sure that both parties to the transfer understand what byte count is expected or if possible have the Talker use the END message to assist in early termination S G 11 The GPIB 232CT records this error when your programming message contains an S mode function and the GPIB 232CT is configured for G mode or your programming message contains a G mode fu
123. n it receives its listen addresses and the Selected Device Clear SDC command it clears both its status buffer and its serial port receive buffer National Instruments Corp 7 13 GPIB 232CT User Manual Chapter 8 G Mode Functions This chapter contains descriptions of the G mode functions that you use to program the GPIB 232CT These functions are in alphabetical order and are formatted to provide you with an easily usable reference Points to Remember e The program examples within the function descriptions are written in Microsoft BASIC Version 3 0 using the GPIB PC function calls of National Instruments The GPIB PC function call WRTS SPSET CHRS 13 CALL IBWRT GPIB232 WRTS automatically sends to the GPIB 232CT its talk address and the programming message spset followed by a carriage return If you are not using the National Instruments GPIB PC software be sure your program properly addresses the GPIB 232CT and the serial device when writing to and reading from them e In the function syntax descriptions arguments shown in square brackets are optional Do not enter the brackets as part of your argument e Terminate each programming message with a carriage return lt CR gt a linefeed lt LF gt or a carriage return followed by a linefeed lt CR gt lt LF gt This is denoted by lt CR gt in the syntax portions of the function descriptions and by CHR 13 in the BASIC examples e To send
124. nction and the GPIB 232CT is configured for S mode S G 17 The GPIB 232CT records this error when your programming message received by the GPIB 232CT does not contain a recognizable function name This can happen if the function name is misspelled or if a transmission error occurred that resulted in the function name being corrupted Check your function name spelling and check serial error to see if a serial port error has been posted National Instruments Corp B 9 GPIB 232CT User Manual Status Information Appendix B Serial Port Error Codes The following paragraphs describe the serial port errors in detail In S mode when a serial port error occurs as the GPIB 232CT receives a programming message the GPIB 232CT posts the error and discards the message If a serial port error occurs in the middle of a data stream following a cmd or wrt function the GPIB 232CT discards that data byte and all subsequent data bytes You can use the spign function to tell the GPIB 232CT to ignore all serial port errors NSER 0 The GPIB 232CT reports this error when the GPIB 232CT detected no serial port error as a result of the last operation EPAR 1 The GPIB 232CT records this error when the parity of the received character is not what was expected This means that 1 or more bits of the received character were corrupted in such a way as to change the character s parity EORN 2 The GPIB 232CT records this error when characters arrive
125. nd expects valid responses within that time It remains Active Controller afterward The GPIB 232CT returns the Parallel Poll Response PPR following the poll in the form of a numeric string representing the decimal value of the response If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable If you passed control to some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted ist ppc ppu and Appendix F Parallel Polling GPIB 232CT User Manual 5 34 National Instruments Corp Chapter 5 S Mode Functions Example 1 PRINT 1 ppc 13 1 0 15 3 0 CHRS 13 rpp Configure 2 devices for parallel polls and poll them response 5 lt CR gt lt LF gt both devices responded positively INPUT 1 PPR Get parallel poll response from serial port buffer and assign it to integer variable PPRS PRINT 1 ppu Unconfigure all devices from parallel polls National Instruments Corp 5 35 GPIB 232CT User Manual S Mode Functions Chapter 5 rsc Request System Control Type Syntax Purpose Remarks See Also Initialization function rsc bool lt CR gt You use rsc if some other device in your G
126. ode name is shown in boldface in the function tables and in the syntax portions of the function descriptions Function Argument Delimiters When you type in a function separate the first argument from the function name with at least one space Separate each additional argument with at least one space or a comma In the syntax portions of the function descriptions in Chapter 5 the information within the square brackets are optional If you want to include optional information do not type the brackets only the information inside the brackets Abbreviations for Arguments The function descriptions in Chapter 5 use abbreviations for some arguments They are as follows addr a GPIB address alist one or more addrs bool a boolean value 1 true on or enable 0 false off or disable GPIB Address Each device on the GPIB has a GPIB address The GPIB 232CT s address is 0 at power on and can be changed using the caddr function Refer to the manuals of your GPIB devices to learn their addresses You will need to know these when you begin to program the GPIB 232CT Only the lower five bits of each GPIB address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary address For example the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 A plus sign separates the primary
127. of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary address Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 If you call Loc with alist the GPIB 232CT places the specified device s in local mode using the Go To Local GTL command If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable National Instruments Corp 5 23 GPIB 232CT User Manual S Mode Functions Chapter 5 If you passed control to some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted If you call Loc without alist and the GPIB 232CT is System Controller the GPIB 232CT returns all devices to local mode by unasserting REN and asserting it again If you call Loc without alist and the GPIB 232
128. of the manual continues If you find errors in the manual please record the page numbers 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
129. of your application program OPEN COM1 9600 8 AS 1 then set the switches on the GPIB 232CT as shown in Figure G S hold e Figure G 5 S mode 8 data bits 1 stop bit even parity 9600 baud If your computer or terminal is other than those described above read your user s manual to learn the default settings of the serial port On a terminal there will be switches or a setup program If you are using Applesoft BASIC or Integer BASIC for your application you should configure for your serial port before you enter BASIC If you are using a version of Microsoft BASIC you can change the serial port characteristics from within BASIC Refer to the OPEN command in your BASIC manual Remember whatever serial port characteristics you decide to use you must set up both your serial device and your GPIB 232CT to identical characteristics GPIB 232CT User Manual G 4 National Instruments Corp Appendix H Sample Programs This appendix contains program examples you can use as guidelines as you start writing programs for the GPIB 232CT The first part of the appendix applies to S mode The remainder of the appendix applies to G mode S Mode Sample Programs The following steps are general programming steps The following pages contain detailed explanations of these steps and show some sample programs 1 Send the stat function to have status information returned to you after your programming message 2 Send seria
130. ogramming Message Format c ccssceeseeseeteees 4 1 Example of a Programming Message 4 1 Example of a Programming Message with Data Stringi eiieeii 4 2 How Messages are Processed cscceeseceeseeeeteeeeneers 4 2 Function Names risene eh eth eva tke aecaotben Ei a 4 2 Function Argument Delimiter 000 0 eee ee eeeeeseeeseeereeeeeeeees 4 3 National Instruments Corp xi GPIB 232CT User Manual Contents Abbreviations for Argument ce eeeseeeeereeseeeeeeeeee 4 3 GPIB AGOIreESS ne eenaa E RE EEA 4 3 Numeric String Argument s sseeesesseesrereerereresesrsrrrrsrereersrereerses 4 4 Status Information s sesseseeesesesserseeseeseesessessessesressesessessessesseseese 4 4 Serial Port Error Handling s seeseeeeeeeeeeeeeeeesereersrerrsrsrsrerrersreee 4 5 GPIB Read and Write Termination Method END and EOS 4 5 S Mode Default Settings 00 0 eseeeeseeseereenereeeneeseeseeeeeee 4 6 List of S Mode Functions by Group ceesesssseeseeteeseeeeeeeeeees 4 7 GPIB PUNCUONS eien A E OREG 4 7 Serial Port F n tionsnass senini 4 10 General Use Functions cesccesceeceeeeeeseeeeesneeseeeees 4 10 Alphabetical List of S Mode Functions 0 cc ceeeeseeeeeeeeeeeees 4 11 Chapter 5 S Mode Functions ois csccssesscsertsanassecteerattnasinscmteconrer coauntretens 5 1 Points to Remember meteren a E EREE 5 1 cac Become Active Controller ccecceeceesseeseeeeeeeeeeeeeeeeeeeeees 5
131. olrx lt CR gt You use xon at the beginning of your program when your serial device uses the XOFF XOFF protocol xon allows the GPIB 232CT to communicate over the serial port using the same protocol as your serial device The argument booltx specifies whether to enable the XON XOFF protocol when sending data out on the serial port When boo1tx is enabled the GPIB 232CT monitors its serial receive buffer for XON XOFF characters as it sends data over the serial port If it receives the XOFF character decimal 19 or lt CTRL gt s it immediately stops sending data When it receives the XON character decimal 17 or lt CTRL gt q it begins sending data again The argument boolrx specifies whether to enable the XON XOFF protocol when receiving data over the serial port When boolrx is enabled as the GPIB 232CT receives data over the serial port it sends XOFF over the serial port if its serial port recive buffer is almost full This tells the sender to stop sending data When the GPIB 232CT has room to safely receive more bytes the GPIB 232CT sends XON over the serial port This tells the sender to begin sending data again Use XON XOFF if your serial device does not recognize the hardware handshake protocol and you are transferring large amounts of data at high speeds Without it you are in danger of overflowing the serial port receive buffers of the GPIB 232CT and the serial device Refer to your serial device s documentation to see if
132. ombination of the two See Figures D 2 and D 3 The standard connector is the Amphenol or Cinch Series 57 Microribbon or Amp Champ type An adapter cable using a non standard cable and or connector is used for special interconnection applications The GPIB uses negative logic with standard TTL logic levels When DAV is true for example it is a TTL low level 0 8V and when DAV is false it is a TTL high level 2 0V GPIB 232CT User Manual D 6 National Instruments Corp Appendix D Operation of the GPIB Figure D 2 Linear Configuration of the GPIB Devices National Instruments Corp D 7 GPIB 232CT User Manual Operation of the GPIB Appendix D A F mm e i GFIE 232CT Tees IHAAEEN ECCIC CETE Figure D 3 Star Configuration of GPIB Devices GPIB 232CT User Manual D 8 National Instruments Corp Appendix D Operation of the GPIB Configuration Requirements To achieve the high data transfer rate that the GPIB was designed for the physical distance between devices and the number of devices on the bus are limited The following restrictions are typical e A maximum separation of 4 m between any two devices and an average separation of 2 m over the entire bus e A maximum total cable length of 20 m No more than 15 devices connected to each bus with at least two thirds powered on Bus extenders are available from National Instruments and other manufacturers for use when these limits mu
133. on after each call An error made early in your application program may not become apparent until a later instruction At that time the error can be more difficult to locate S 16384 The TIMO bit specifies whether a timeout has occurred The TIMO bit is set in the status word following a call to wait if the TIMO bit of the wait mask parameter is also set and if the wait has exceeded the time limit value that is set by the tmo call The TIMO bit is also set following a call to any of the I O functions for example rd wrt and cmd if a timeout occurs during a call The TIMO bit is cleared in the status word in all other circumstances National Instruments Corp B 1 GPIB 232CT User Manual Status Information Appendix B END SRQI CMPL LOK S 8192 The END bit specifies whether the END or EOS message has been received The END bit is set in the status word following a rd function if the END or EOS message was detected during the read While the GPIB 232CT is performing a shadow handshake as a result of the gts function any other function call can return a status word with the END bit set if the END or EOS message occurred before or during that call The END bit is cleared in the status word at the start of any subsequent programming message S 4096 The SRQI bit specifies whether a device is requesting service This bit is set in the status word whenever the SRQ line is asserted The bit is cleared whenever the GPIB SRQ
134. on of each function description GPIB 232CT User Manual 5 2 National Instruments Corp Chapter 5 S Mode Functions cac Become Active Controller Type Syntax Purpose Remarks See Also Examples Low level Controller function cac bool lt CR gt You use cac to change the GPIB 232CT from Standby Controller to Active Controller when the I O and bus management functions do not meet the needs of your device cac gives you more precise control over the GPIB than the T O and bus management functions If the argument boo is 0 the GPIB 232CT takes control immediately that is it takes control asynchronously If the argument bool is 1 the GPIB 232CT takes control after any handshake that is in progress completes that is it takes control synchronously If you call cac without an argument the GPIB 232CT returns to you the current Controller status which is 0 if the GPIB 232CT is not the Active Controller and 1 if the GPIB 232CT is the Active Controller If you call cac with an argument and the GPIB 232CT is not CIC the GPIB 232CT records the ECIC error The power on Controller status of the GPIB 232CT is Idle Controller gts and sic 1 PRINT 1 cac 0 Take control immediately 2 PRINT 1 cac 1 Take control synchronously 3 PRINT 1 CAC Are we the Active Controller response 1 lt CR gt lt LF gt yes we re CAC National Instruments Corp 5 3 GPIB 232CT User Manual
135. or comma In the syntax portions of the function descriptions in Chapter 8 the square brackets that enclose some arguments indicate that those arguments are optional Do not enter the brackets as part of your arguments Abbreviation for Argument The term bool is an abbreviation used for an argument in the function descriptions The value for bool is 1 true on or enable or 0 false off or disable GPIB 610 User Manual 7 2 National Instruments Corp Chapter 7 Programming in G Mode Status Information The function descriptions in Chapter 8 explain that the GPIB 232CT records specific status and error information This means that it stores that information in its memory so that it is available when you request it The function descriptions also explain that the GPIB 232CT returns to you certain information This means that the GPIB 232CT sends information to you over the GPIB Communicating with the GPIB 232CT and the Serial Device The GPIB 232CT knows the type of GPIB data it is processing by using dual addressing With dual addressing the GPIB 232CT recognizes two different GPIB addresses The first is the GPIB 232CT s address The second is the serial device s address Address of the GPIB 232CT The address of the GPIB 232CT is the primary address you set on the configuration switch with secondary addressing disabled Address of the Serial Device The address of the serial device is the GPIB 232CT prim
136. ormat and how they are processed along with the functions and function arguments that make up the programming messages Programming Messages You program the GPIB 232CT by sending it programming messages which are ASCII strings and data strings by way of its serial port Programming Message Format A programming message consists of a function name one or more arguments optional followed by a carriage return lt CR gt a linefeed lt LF gt or a carriage return followed by a linefeed lt CR gt lt LF gt You can enter programming messages in any combination of uppercase and lowercase letters Example of a Programming Message The following line of BASIC code PRINT 1 clr 3 4 contains the function name clr and the arguments 3 and 4 This programming message tells the GPIB 232CT to clear the devices at GPIB addresses 3 and 4 PRINT 1 is the BASIC command to send characters to the serial port after the serial port has been opened with the OPEN COM statement In this example BASIC automatically sends a lt CR gt so it is not necessary to include it here National Instruments Corp 4 GPIB 232CT User Manual Programming in S Mode Chapter 4 Example of a Programming Message with Data String The following lines of BASIC code PRINT 1 wrt 2 PRINT 1 IN CI contain the function name wrt the argument 2 and the data string IN CI This programming message is telling the GPIB 232CT to wr
137. ou call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable National Instruments Corp 5 29 GPIB 232CT User Manual S Mode Functions Chapter 5 If you passed control to some other GPIB device control must be passed back to you or you must send IFC to make yourself CIC before making this call Otherwise the ECIC error will be posted If the address of the GPIB 232CT is included in alist the GPIB 232CT disables itself from responding to parallel polls See Also ist ppc rpp and Appendix F Parallel Polling Examples 1 PRINT 1 ppu 14 Send the PPU command to device 14 2 PRINT 1 PPU Send the PPU command to all devices GPIB 232CT User Manual 5 30 National Instruments Corp Chapter 5 S Mode Functions rd Read Data Type Syntax Purpose Remarks T O function rd count addr lt CR gt You use rd to read data from the GPIB The argument count is a numeric string preceded by a number sign count specifies the number of bytes to read count must not contain a comma It can specify a number between 1 and 65535 The argument addr is a device address that specifies the address of the device to be addressed as a Talker addr consists of a primary address and a secondary address The secondary address is separated from the primary
138. pectively which indicates that the GPIB 232CT is operating in G mode Switches 4 through 8 are OFF OFF ON OFF and ON respectively This configures the GPIB 232CT at GPIB address 5 and the serial device at address 6 ELC Figure 6 2 Example Settings for Switch U22 Note Switch U20 is not used by S or G mode but can be used for user applications in IBCL mode Step 4 Connect the Cables Connect the cables as follows 1 Connect the serial cable to the GPIB 232CT 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 obey all RS 232 cabling restrictions 2 Connect the GPIB cable to the GPIB 232CT and tighten the thumb screws on the connector Connect the other end to your GPIB system Be sure to obey 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 232CT then plug the supply into an AC outlet of the correct voltage GPIB 232CT User Manual 6 6 National Instruments Corp Chapter 6 Installation and Configuration in G Mode Step 5 Power on the Unit Power on your GPIB 232CT by using the front panel rocker switch The POWER LED should come on immediately The READY indicator should come on after the GPIB 232CT has passed its power on self test indicating the unit is ready for operation If th
139. ple this step is not necessary Step 4 Communicate with rd and wrt Functions Communicate with the device using rd and wrt programming messages Here is the heart of the program 10 DS CHRS 4 20 PRINT D PR 2 REM INPUT FROM SLOT 2 MODEM 30 PRINT DS IN 2 REM OUTPUT TO SLOT 2 MODEM 40 PRINT 60 PRINT WRT 6 REM WRITE STRING TO DEVICE 6 70 PRINT CTT 90 PRINT RD 20 6 REM READ UP TO 20 BYTES FROM 95 REM DEVICE 6 100 INPUT RESPS REM INPUT FREQUENCY AND BYTE 105 REM COUNT 110 PRINT D PR 0 PRINT RESP PRINT D PR 2 140 PRINT DS PR 0 National Instruments Corp H 9 GPIB 232CT User Manual Sample Programs Appendix H 150 PRINT D IN 0 500 END G Mode Sample Programs The following steps are general programming steps The following pages contain detailed explanations of these steps and show some sample programs 1 Send the stat function to have status information returned to you after your programming message 2 Send GPIB initialization functions if you need to change default GPIB settings 3 Send serial port initialization functions if you need to change default serial port settings 4 Communicate with the serial device and obtain status from the GPIB 232CT if desired After you initialize the GPIB 232CT you may only need to perform reads and writes from the serial device To send data to the device you must address the device To send programming messages
140. pter 1 GPIB 232CT Specifications Tables 1 1 through 1 3 specify the electrical environmental and physical characteristics of the GPIB 232CT Table 1 1 Electrical Characteristics Man ae a aa 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 unregulated Current 640 mA typical 1 500 mA max Table 1 2 Environmental Characteristics ge Characteristic Specification Operating Temperature 0 to 50 C Storage Temperature 0 to 70 C Relative Humidity 10 to 95 noncondensing conditions Noise Emissions FCC Class A Verified GPIB 232CT User Manual 1 4 National Instruments Corp Chapter 1 Description of the GPIB 232CT Table 1 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 Single or dual kits available Weight 28 oz without power supply unit The GPIB 232CT Front Panel The front panel of the GPIB 232CT is shown in Figure 1 2 The power switch and six Light Emitting Diodes LEDs are mounted on the GPIB 232CT front panel INSTRUMENTS GPIB 232CT IEEE 488 lt gt RS 232 CONTROLLER fenton e o e POWER READY TALK LISTEN SRQ ATN Figure 1 2 The GPIB 232CT Front Panel National Instruments Corp 1 5 GPIB 232CT User Manual Description of th
141. r a 115V or 230V wall mount supply Verify that the voltage on the supply matches the voltage that is supplied in your area Caution Operating the unit at any voltage other than the one specified could damage the unit Step 3 Configure the Operating Parameters The GPIB 232CT is shipped from the factory configured to operate in S mode To configure the GPIB 232CT to operate in G mode 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 sides 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 switch U22 on the printed wire board 5 Set the switches for the desired mode of operation Refer to the following section Set Configuration Switches Caution Most of the circuitry in the GPIB 232CT 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 GPIB 232CT User Manual 6 2 National Instruments Corp Chapter 6 Installation and Configuration in G Mode Set Configuration Switches The DIP switch at location U22 on the printed wire board is used to configure the GPIB address of the GPIB 232CT while in G mode The DIP switch s
142. ranslation to the GPIB The argument alist isa list of addrs separated by commas or spaces addrs are addresses that specify the GPIB addresses of the Listener or Listeners if more than one address is given A device address consists of a primary address and an optional secondary address The secondary address is separated from the primary address by a plus sign Only the lower five bits of each address are significant These bits can be in the range from 0 through 30 for both the primary and the secondary addresses Therefore the binary value 01100010 decimal 98 is interpreted as decimal 2 The following examples all specify a primary address of 0 and a secondary address of 2 The listen address is 32 the talk address is 64 and the secondary address is 2 or 98 which are equivalent 0 2 or 0 98 or 324 98 or 0 x62 When count is not specified the GPIB 232CT recognizes the end of the data string when it encounters a carriage return GPIB 232CT User Manual 5 60 National Instruments Corp Chapter 5 See Also S Mode Functions or a linefeed count is required when your data string contains embedded carriage return or linefeed characters If you specify an address list the GPIB 232CT must be CIC to perform the addressing If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to m
143. rinter you must tell the GPIB 232CT to watch for XON XOFF characters from the printer Do this by first addressing the GPIB 232CT to listen by sending its listen address Then send it the programming message xon 1 The GPIB 232CT interprets this programming message and acts upon it without sending any data on to the serial device Next address the serial device to listen by sending to the GPIB 232CT the serial device listen address Then send the data over the GPIB The GPIB 232CT sends that data on to the printer without examining that data for meaning The LISTEN LED on the GPIB 232CT front panel is lit when either the GPIB 232CT is addressed to listen or the serial device is addressed to listen GPIB 610 User Manual 7 4 National Instruments Corp Chapter 7 Programming in G Mode The GPIB 232CT and Serial Device as Talker When the GPIB 232CT receives its own talk address it sends out status information When the GPIB 232CT receives the serial device talk address it sends all data received from the serial device to the GPIB For example let s say your serial device is programmed to perform some calculations and you want it to return data to you First address the serial device to talk by sending to the GPIB 232CT the serial device talk address Next perform a GPIB read of 100 bytes The GPIB 232CT retrieves 100 bytes from its serial port receive buffer and sends them to you Now find out if the serial device has sent
144. riter The following program example prints the message Hello World Getting Ready to Program First set the GPIB 232CT configuration switch with a primary address of 18 as shown in Figure H 5 ae hh Figure H 5 G mode primary GPIB address 18 Next check the DIP switch settings on the Imagewriter Switches 2 1 and 2 2 should be closed for 9600 baud rate The serial port characteristics of the GPIB 232CT must match those of the serial device The baud rate of the printer is 9600 Since the configurations match there is no need to initialize the software of the serial port GPIB 232CT User Manual H 14 National Instruments Corp Appendix H Sample Programs Programming Steps Step 1 stat Function Send stat c nif you want status information returned after each programming message Next use the ibrd function to read back status after this string is sent and after every other string sent to the GPIB 232CT until continuous status is disabled Step 2 GPIB Initialization Functions If there are GPIB functions on the GPIB 232CT you wish to change from their default settings send strings to the GPIB 232CT at this time No changes are necessary to communicate with this plotter Step 3 Serial Port Initialization Functions Next change any serial port characteristics if necessary If you have set up the printer as previously described no software initialization is necessary Step 4 Communicate with the Printer Be
145. rrive at the serial port before processing it This slows down the overall performance of your program If speed is a primary concern disable continuous status reporting Examples 1 10 20 30 40 50 60 70 80 90 100 400 410 PRINT 1 stat n Get GPIB 232CT status REM GPIB 232CT responds with REM 340 lt CR gt lt LF gt 0 lt CR gt lt LF gt 0 lt CR gt lt LF gt 0 lt CR gt lt LF gt REM Now read status into variables INPUT 1 STATUS GPIBERR SPERR COUNTS REM Go to error routine at 500 if error IF STATUS lt 0 THEN GOTO 500 REM Go to SRQ service routine if SRO is REM asserted IF STATUS AND amp H1000 THEN GOTO 400 REM REM Place code here to service SRQ National Instruments Corp 5 51 GPIB 232CT User Manual S Mode Functions Chapter 5 420 REM 500 REM Print GPIB error and serial error values 510 REM to determine what errors occurred 520 PRINT GPIB error GPIBERR 530 PRINT Serial error SPERR 540 STOP 2 10 PRINT 1 stat s 20 REM If it has just read 3 bytes from the 30 REM GPIB the GPIB 232CT responds with 40 REM CMPL REM ATN LACS lt CR gt lt LF gt NGER lt CR gt lt LF gt 50 REM NSER lt CR gt lt LF gt 3 lt CR gt lt LF gt 3 The following list illustrates what appears on the screen when you are programming the GPIB 232CT from a terminal Programming messages you enter are in regular type GPIB 232CT responses are in boldface The statements in parentheses are
146. s D 6 Configuration Restrictions cceeeeseesceseeseeteeseeseeeteeseeeseeeees D 9 Related Document ss3ciecssiestccgsscstasesastseseidacaieassienisgstanciadsceectense D 9 Appendix E Common Questions 0 c ccccccccccsccscssssesessesesesesesseseseeseseseesseesees E 1 SMode erpa aa an A Eaa AE EEEn TE EE EEA A iaaa E 1 EMO GE ahanenn ee tita A EAE A E A S E 3 Appendix F Parallel Polling ooo rertessiceetarteass ayer totetertisiad natin e Gta eataetna F 1 Operations eeeiiess reisecderehasercas E a mieten n F 1 GConfiguration iss isitet tthe Git Sissies teil iea tied F 2 The Parallel Pollissscessesiessisavssceinesazcitas riein aa Ear a F 3 Disabling Parallel Poll Response sseesseeeeeeeeeeeseeereeeerererrerees F 3 S Mode Example a e NES F 3 Appendix G Setting SS WEICIES 1555 4 crea artis Pacts le cine x tated omcerna tine are G 1 Appendix H Sample Programs 0 cccccccssssssssessesscsessssseseessscssessssesceesasesceneass H 1 S Mode Sample Programs ecceesccessceeeseeeeseeceseeeeseeseseeeeneeeeas H 1 Using an HP 7475A Plotter with a Terminal cece H 2 Getting Ready to Program ecceeeeesceeeseeeeneeeeeeeenes H 2 Programming Steps cceccesceesceeseeeeeeeeeeeeeseeeeeeseens H 3 Step 1 stat Function eee eeeeeeeeeeeeteeeeee H 3 Step 2 Serial Port Functions 0 0 0 H 3 Step 3 GPIB Initialization Functions H 4 National Instruments Corp
147. s RAM buffer is nearly full the GPIB 232CT is capable of handshaking with the serial host to stop data transmission When the buffer is almost empty the GPIB 232CT can again handshake with the serial host to start data transmission The GPIB 232CT is capable of using both the XON XOFF and the hardware handshaking protocols The hardware handshake is always active during RS 232 transfers You can turn the XON XOFF handshake on or off by calling xon Hardware Handshake 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 232CT is ready to accept serial data it asserts the RTS line This signal remains asserted until the GPIB 232CT s data buffer is almost full At this point the GPIB 232CT unasserts the RTS line signaling to the serial host that the GPIB 232CT 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 232CT asserts RTS when it is again ready to receive serial data The GPIB 232CT is also able to suspend transmission when the serial device is no longer ready to accept data The GPIB 232CT is configured to immediately stop transmission of serial data when CTS becomes unasserted The GPIB 232CT resumes transmission as soon as CTS is reasserted Because most serial devices use the same form of hardware handshaking as the GPIB
148. s cleared whenever the GPIB 232CT detects Interface Clear IFC from some other device that is System Controller or when the GPIB 232CT passes control to another device S 16 The ATN bit specifies the state of the GPIB Attention ATN line The ATN bit is set whenever the GPIB ATN line is asserted and cleared when the ATN line is unasserted S 8 The TACS bit specifies whether the GPIB 232CT has been addressed as a Talker The TACS bit is set whenever the GPIB 232CT detects that its talk address and secondary address if enabled has been sent either by the GPIB 232CT itself or by another Controller The TACS bit is cleared whenever the GPIB 232CT detects the Untalk UNT command a talk address other than its own its own listen address or Interface Clear IFC National Instruments Corp B 3 GPIB 232CT User Manual Status Information Appendix B LACS DTAS DCAS S 4 The LACS bit specifies whether the GPIB 232CT has been addressed as a Listener The LACS bit is set whenever the GPIB 232CT detects that its listen address and secondary address if enabled has been sent either by the GPIB 232CT itself or by another Controller The LACS bit is also set whenever the GPIB 232CT shadow handshakes as a result of the gts function The LACS bit is cleared whenever the GPIB 232CT detects that the Unlisten UNL command its own talk address Interface Clear IFC or gts is called without shadow handshake S 2 The DTAS bit
149. s is stored as a 16 bit integer Each bit in the integer represents a single condition A bit value of 1 indicates that the corresponding condition is in effect a bit value of zero indicates that the condition is not in effect Since more than one GPIB 232CT condition can exist at one time more than one bit can be set in status The National Instruments Corp 5 47 GPIB 232CT User Manual S Mode Functions Chapter 5 highest order bit of status also called the sign bit is set when the GPIB 232CT detects either a GPIB error or a serial port error Consequently when status is negative an error condition exists and when status is positive no error condition exists GPIB error represents a single GPIB error condition present Serial error represents a single serial error condition present count is the number of bytes transferred over the GPIB by the last rd wrt or cmd function Table 5 2 GPIB Status Conditions Numeric Symbolic Value n Value s Description 32768 ERR Error detected Timeout 15 8192 END EOI or EOS detected SRQ detected while CIC 13 2048 Reserved 1024 Reserved Reserved CMPL Operation completed Lockout state 64 REM Remote state 6 32 CIC Controller In Charge 5 16 ATN Attention asserted 4 continues GPIB 232CT User Manual 5 48 National Instruments Corp Chapter 5 S Mode Functions Table 5 2 GPIB Status Conditions con
150. so use the GPIB 232CT in the S mode Or is the serial device going to be only a Talker and or Listener where a GPIB device s will manage the bus and send and receive data to and from the serial device If so use the GPIB 232CT in the G mode Figure 2 1 shows the GPIB 232CT operating in the S mode where a personal computer is controlling a GPIB plotter National Instruments Corp 2 1 GPIB 232CT User Manual The GPIB 232CT Modes of Operation Chapter 2 OFIE device Figure 2 1 Personal Computer Controlling a GPIB Plotter Figure 2 2 shows the GPIB 232CT operating in the G mode where the GPIB 232CT enables a serial printer to be programmed from a GPIB Controller Coerial cable Serial device Figure 2 2 A Serial Printer Connected to a GPIB Controller Now turn to Chapter 3 for S mode installation and configuration then to Chapters 4 and 5 to begin programming your GPIB 232CT in S mode Or turn to Chapter 6 for G mode installation and configuration then to Chapters 7 and 8 to begin programming your GPIB 232CT in G mode GPIB 232CT User Manual 2 2 National Instruments Corp Chapter 3 Installation and Configuration in S Mode If you plan to operate in S mode use this chapter to install and configure the GPIB 232CT Then read Chapters 4 and 5 to learn about its programming messages Installation There are five basic steps to installing the GPIB 232CT 1 Inspect the GPIB 232CT for damage that may hav
151. ss 11 to listen and GPIB 232CT at address 0 to talk Device Listen address is 43 or ASCII and GPIB 232CT talk address is 64 or ASCII Write the string ABCDE to device at address 11 cmd CHRS 13 _ W CHRS 9 Pass control to device 23 CHRS 9 TCT command 5 10 National Instruments Corp Chapter 5 echo Type Syntax Purpose Remarks Examples S Mode Functions Echo Characters Received from Serial Port Serial Port function echo bool lt CR gt You use echo when a terminal is connected to the GPIB 232CT and you wish to display what you type on the screen of the terminal If the argument bool is 1 characters received from the serial port are echoed back to the serial port If the argument bool is 0 characters are not echoed If the argument bool is 1 and echoing was previously disabled characters will not be echoed until this command has been completely processed that is the next programming message will be echoed If you call echo without an argument the GPIB 232CT returns the current setting The following examples show commands as you would enter them at a terminal 1 echo 1 lt CR gt Turn on character echoing 2 ECHO 0 lt CR gt Disable character echoing 3 echo lt CR gt What is the current echo status response 0 lt CR gt lt LF gt character echo is National Instruments Corp 5 11 GPIB 232CT User Manual S Mo
152. ssccceesssssssssceeeees 7 7 Table 7 2 Serial Port Characteristics ccccccccccccssssssssscesessssseeeseees 7 7 Table 7 3 GPIB Configuration Functions ccccsseseeeeeseeeeeeeeees 7 8 Table 7 4 Serial Port Configuration Functions 0 0 0 0 cesses 7 9 Table 7 5 General Use Functions 0 0 ccccccscssscccsessssssesseeseesseseeeees 7 9 Table 7 6 GPIB 232CT Functions ccccccccccccccsssssecesesesesesseeseeees 7 10 Table 7 7 Serial Poll Response Byte eee eee eeeereeeteeenees 7 11 Table 8 1 Data Transfer Termination Methods ccccccceeeeeeees 8 5 Table 8 2 SRQ Mask Bits ccc cccccccccessecceessceceesseeceesssecessaeees 8 12 Table 8 3 GPIB 232CT Status Conditions cccccccccccccccseseseeeeees 8 15 Table 8 4 GPIB Error Conditions ohan aias 8 16 Table 8 5 Serial Error Conditions ccccccccccccccseesssssssseeesesssseesees 8 17 GPIB 232CT User Manual xviii National Instruments Corp Contents Table C 1 RS 232 Serial Port Pinouts 0cccceeeeeccccessessssssceseeeees C 2 National Instruments Corp XIX GPIB 232CT User Manual Chapter 1 Description of the GPIB 232CT Introduction The GPIB 232CT shown in Figure 1 1 is a high performance serial to GPIB interface It provides a computer with an RS 232 port a means of controlling talking and listening on the GPIB The GPIB 232CT is also capable of interfacing RS 232 instruments and peripherals to the GPIB The G
153. st be exceeded Related Document For more information on topics covered in this appendix consult JEEE Standard Digital Interface for Programmable Instrumentation ANSI TEEE Std 488 1987 National Instruments Corp D 9 GPIB 232CT User Manual Appendix E Common Questions This appendix consists of two sections The first section answers questions about S mode The second section answers questions about G mode S Mode Question Why does the manual suggest that I use INPUTS sometimes and LINE INPUT at other times Microsoft suggests using INPUTS to read from the serial port Answer Use LINE INPUT to read status information from the GPIB 232CT GPIB 232CT software formats its status information so that your BASIC program can easily read and interpret each of its pieces Each logical piece of status information is followed by a carriage return lt CR gt and linefeed lt LF gt LINE INPUT allows you to easily read each piece of status information and assign it to a variable Use INPUTS to read a data string from your GPIB device INPUTS requires that you know the exact number of characters you wish to read from the serial port When reading status information from the GPIB 232CT this is not always possible since the responses can vary in length from one call to the next However when reading a data string from your GPIB device you requested a certain number of bytes and you should use INPUTS to read the number of by
154. status You can write this later Add the following line to call the subroutine GOSUB status Step 2 Serial Port Functions Send serial port initialization programming messages if necessary For this example this step is not necessary Step 3 GPIB Initialization Functions Send GPIB initialization programming messages if necessary For this example this step is not necessary GPIB 232CT User Manual H 6 National Instruments Corp Appendix H Sample Programs Step 4 Communicate with rd and wrt Functions Communicate with the device using wrt programming messages and reading back status after each Here is the heart of the program After each wrt string call the subroutine status which will check for errors The plotter s GPIB address is 5 OPEN com1 9600 n 7 1 AS 1 PRINT 1 stat c n GOSUB status PRINT 1 wrt 5 PRINT 1 in sp1 pa1000 3000 ci500 GOSUB status END status STAT S VAL LINE INPUT 1 status LINE INPUT 1 gpiberrs LINE INPUT 1 sperrs LINE INPUT 1 cnt PRINT status gpiberr sperr cnt if stat lt 0 GOSUB error error REM Place your code to handle errors here STOP National Instruments Corp H 7 GPIB 232CT User Manual Sample Programs Appendix H Programming a Tektronix 2445 Oscilloscope from an Apple IIc This example shows how to use an Apple IIc to control a Tektronix 2445 oscilloscope The Apple IIc s serial port is configured w
155. t function The errors reported correspond to the previous programming message For example if you call wrt and then stat s any errors returned to you correspond to errors in the wrt programming message not stat However if status is returned in continuous mode the status information corresponds to the current programming message For example suppose you call stat c s to set up continuous GPIB 232CT User Manual 5 50 National Instruments Corp Chapter 5 S Mode Functions status reporting After reading the status information returned for the stat call you call wrt The GPIB 232CT then returns the status information that corresponds to the wrt message Refer to the following examples for ways in which to make use of the status information When you wish to begin continuous status reporting send the stat c s stat c n orstat c n s programming message Status information will be immediately returned indicating the current status conditions When you call stat with both s and n the numeric status is always returned first If you call stat without an argument continuous status reporting is disabled Notice that when you send several programming messages to the GPIB 232CT it buffers them and processes each one without any delay in between However if you enable continuous status reporting and check the status of each programming message before sending the next the GPIB 232CT waits for each subsequent programming message to a
156. t an argument the GPIB 232CT returns to you a 1 to indicate END termination is currently enabled or a 0 to indicate END termination is currently disabled The assignment made by eot remains in effect until you call eot again call on1 or you turn off the GPIB 232CT The GPIB 232CT sends the END message by asserting the GPIB EOI signal during the last byte of a data transfer eot is used primarily to send variable length data Chapter 4 the section entitled GPIB Read and Write Termination Method National Instruments Corp 5 15 GPIB 232CT User Manual S Mode Functions Examples 1 PRINT 1 eot 0 2 PRINT 1 EOT 1 PRINT 1 WRT 3 PRINT 1 ABCDE 3 PRINT 1 eot response 1 lt CR gt lt LF gt GPIB 232CT User Manual Chapter 5 Disable END termination Send END with last byte Write data to device at address 3 The EOI line is automatically asserted when the last byte the letter E is sent to tell the Listeners it is the last byte of data What is the current EOT setting END termination is currently enabled 5 16 National Instruments Corp Chapter 5 S Mode Functions gts Go from Active Controller to Standby Type Specialized Controller function Syntax gts bool lt CR gt Purpose You use gts to change the GPIB 232CT from Active Controller to Standby Controller You use gts when the I O and bus management functions do not meet the needs of your
157. t is in effect for the cmd rd and wrt functions If the GPIB 232CT cannot complete any of these functions within the period of time set by timeio it aborts the function and records the EABO error Bytes that were transferred before the timeout are not affected The timeio time limit is also the maximum amount of time the wait function waits when you call it with the TIMO bit set in the wait mask The timesp time limit is in effect only for the rsp function If a polled device fails to respond within the amount of time indicated by timesp the GPIB 232CT returns an error flag National Instruments Corp 5 53 GPIB 232CT User Manual S Mode Functions Chapter 5 See Also Examples 1 PRINT If you want to change only the timeout value for serial polls a comma must precede the serial poll timeout value If you call tmo without an argument the GPIB 232CT returns a numeric string representing the current timeout settings It records the EARG error if you specify a time value outside the range 00001 to 3600 The assignment made by this function remains in effect until you call tmo again call on1 or turn off the GPIB 232CT 2 PRINT rsp 1 tmo 30 Set timeout for I O operations to 30 seconds 1 tmo Print current timeout settings response 30 1 lt CR gt lt LF gt 3 PRINT 1 tmo 1 Set serial poll timeout for one second leave I O timeout unchanged GPIB 232CT User Manua
158. te count to that which is expected by the Controller or to resolve the situation on the Controller s end S 3 The GPIB 232CT records this error when it is not addressed to listen or to talk before read and write calls when it is not the Controller In Charge The remedy is to be sure that the Controller addresses the GPIB 232CT to talk or listen before attempting the wrt or rd The GPIB 232CT also records this error during the function gts when the shadow handshake feature is requested and the GPIB ATN line is already unasserted In this case the shadow handshake is not possible and the error is recorded to notify you of that fact gts should almost never be called except immediately after a cmd call cmd causes ATN to be asserted National Instruments Corp B 7 GPIB 232CT User Manual Status Information Appendix B EARG ESAC S G 4 The GPIB 232CT records this error when you pass an invalid argument to a function call The following are some examples e tmo called with a value not in the range 00001 to 3600 e sic called with a value not in the range 0001 to 3600 e eos called with meaningless termination method identifiers e caddr called with the value 31 e ppc called with illegal parallel poll configurations If your programming message contains more than one argument and you get this error the GPIB 232CT discards all arguments and does not perform the function This also can be caused by a transmissio
159. tempting to communicate with the GPIB 232CT Then set the configuration switch on the GPIB 232CT to match your serial port characteristics For example for Microsoft BASIC on a Macintosh the default characteristics are as follows e baud rate 300 e parity even e databits 7 e stop bits 1 If these defaults meet your needs set the switches on the GPIB 232CT as shown in Figure G 1 Eh Figure G 1 S mode 7 data bits 1 stop bit even parity 300 baud National Instruments Corp G 1 GPIB 232CT User Manual Setting Switches Appendix G In many cases you will want to change the default characteristics of the serial port on the Macintosh For instance you may want to run at a higher baud rate and you may want to send 8 bit data bytes for binary data that will be sent to the GPIB device To change the default characteristics to 19 2K baud and 8 bit data from within Microsoft BASIC place the following BASIC statement at the beginning of your program OPEN COM1 19200 8 AS 1 then set the switches on the GPIB 232CT as shown in Figure G 2 hd falala Figure G 2 S mode 8 data bits 1 stop bit even parity 19200 baud As another example if your computer is an Apple IIc the default characteristics are as follows e baud rate 9600 e parity none e databits 8 e stop bits 1 If these default characteristics meet your needs set the switches on the GPIB 232CT as shown in Figure G 3 GPIB 232CT User Man
160. ter 4 Programming in S Mode Serial Port Error Handling The GPIB 232CT continuously monitors the serial port for transmission errors If it encounters an error in the serial data the GPIB 232CT records the error You can program the GPIB 232CT to ignore serial port errors using the spign function GPIB Read and Write Termination Method END and EOS You program the GPIB 232CT to Talk in order to send data messages over the GPIB and to Listen in order to receive data messages from the GPIB The IEEE 488 specification defines two ways that GPIB Talkers and Listeners can identify the last byte of data messages END and EOS The two methods permit a Talker to send data messages of any length without the Listener s knowing in advance the number of bytes in the transmission END message The Talker asserts the EOI End Or Identify signal while the last data byte is being transmitted The Listener stops reading when it detects a data byte accompanied by EOI EOS character The Talker sends an EOS end of string character at the end of its data string The Listener stops receiving data when it detects the EOS character Either a 7 bit ASCII character or a full 8 bit binary byte can be used The two methods can be used individually or in combination It is important that the Listener be configured to detect the end of a transmission The GPIB 232CT always terminates GPIB rd operations on the END message Using the eos and eot functions
161. tes you requested in your rd function The GPIB 232CT appends to the end of the data string a string containing the number of bytes that were actually read from the GPIB When you have read in the data bytes using INPUTS use LINE INPUT to read the string containing the byte count Refer to the example following the rd function description in Chapter 5 National Instruments Corp E 1 GPIB 232CT User Manual Common Questions Appendix E Question When I use LINE INPUT my strings are usually preceded by a linefeed lt LF gt and followed by a carriage return lt CR gt Why don t my strings contain both a carriage return and linefeed at the end Answer LINE INPUT stops reading when a carriage return is seen and does not skip over the linefeed in the sequence The linefeed is not read until the following LINE INPUT In most cases you will be using the val function to convert the string to a value and a leading linefeed is ignored Question I sent the programming message rsp 10 to the GPIB 232CT to serial poll device 10 Then I used LINE INPUT to read the response byte and got nothing but a carriage return and linefeed lt CR gt lt LF gt as a response Am I doing something wrong Answer No To conduct a serial poll the GPIB 232CT must be Controller In Charge or it must be able to become Controller In Charge If the GPIB 232CT cannot become Controller In Charge no serial poll is conducted and therefore you will not
162. th an IBM PC This example shows how to write a program on an IBM PC using Microsoft BASIC to draw a circle using an HP 7475A Plotter Getting Ready to Program Before you start programming determine the serial port settings you will use Figure H 2 shows how to configure the GPIB 232CT for this example using the following settings e baud rate 9600 e parity none e databits 7 e stop bits 1 TEPE Figure H 2 S mode 7 data bits 1 stop bit no parity 9600 baud Next connect the serial cable to the serial port of your computer and to the GPIB 232CT Connect the GPIB cable to your device and the GPIB 232CT Power on the GPIB 232CT National Instruments Corp H 5 GPIB 232CT User Manual Sample Programs Appendix H Programming Steps Step 1 stat Function In BASIC before reading or writing to the serial port a device must be opened Place the following BASIC statement at the beginning of your program to open and configure the serial port COM1 and name it device 1 OPEN COM1 9600 n 7 1 as 1 You will now use PRINT 1 to redirect strings to the serial port Now send the stat function if you want status information returned after every programming message To do this include the following code in your program PRINT 1 stat c n After you send this programming message you can expect four lines of data at the serial port each line is terminated by lt CR gt lt LF gt For now call a subroutine to check the
163. the Cables Connect the cables as follows 1 Connect the serial cable to the GPIB 232CT 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 obey all RS 232 cabling restrictions 2 Connect the GPIB cable to the GPIB 232CT and tighten the thumb screws on the connector Connect the other end to your GPIB system Be sure to obey 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 232CT then plug the supply into an AC outlet of the correct voltage Step 5 Power on the Unit Power on your GPIB 232CT by using the front panel rocker switch The POWER LED should come on immediately The READY indicator should come on after the GPIB 232CT 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 National Instruments Corp 3 5 GPIB 232CT User Manual Chapter 4 Programming in S Mode This chapter describes how to program the GPIB 232CT in S mode using programming messages and data strings It describes programming messages their f
164. the GPIB 232CT is receiving data over the serial port it sends XOFF over the serial port if its serial receive buffer is almost full This tells the sender to stop sending data When the GPIB 232CT serial port receive buffer has room to safely receive more bytes the GPIB 232CT sends XON over the serial port This tells the sender to begin sending data again You should use XON XOFF when your computer or terminal does not recognize the hardware handshake protocol and you are transferring very large amounts of data greater than the serial port buffer size Without it you could be in danger of overflowing either the GPIB 232CT or your computer s internal buffer When would you want to enable the protocol in one case and not the other Some computers use XON XOFF protocol when transmitting data but not when receiving data In this National Instruments Corp 5 63 GPIB 232CT User Manual S Mode Functions Chapter 5 case you might configure the GPIB 232CT using the second example Notice that the comma must precede the argument in this case The power on default is that XON XOFF for both cases is disabled If you call xon without an argument the GPIB 232CT returns to you the current settings 1 protocol enabled 0 protocol disabled Examples 1 PRINT 1 2 PRINT 1 3 PRINT 1 response 4 PRINT 1 XON 1 1 XON 0 1 XON 0 1 lt CR gt lt LF gt XON 0 GPIB 232CT User M
165. the status information will be returned in symbolic format that is as mnemonic strings c specifies that the status will be returned after each programming message eliminating the need to call stat after each programming message Normally you use s or symbolic format only when you are debugging your code and you want to print the mnemonic for each piece of status information The status information returned by the GPIB 232CT contains four pieces of information the GPIB 232CT status a GPIB error code a serial error code and a count The GPIB 232CT returns a lt CR gt lt LF gt following each piece of the response It asserts EOI with the final lt LF gt that comes after count Status represents a combination of GPIB 232CT conditions Internally in the GPIB 232CT status is stored as a 16 bit integer Each bit in the integer represents a single condition A bit value of 1 indicates the corresponding condition is in effect a bit value of 0 indicates the condition is not in effect Since more than one GPIB 232CT condition can exist at one time more than one bit can be set in status The highest order bit of status also called the sign bit is set when the GPIB 232CT detects either a GPIB error or a serial port error GPIB 232CT User Manual 8 14 National Instruments Corp Chapter 8 G Mode Functions Consequently when status is negative an error condition exists when status is positive no error condition exists GPIB error r
166. tinued ne a Numeric Symbolic Value n Value s Description TACS Talker active LACS Listener active DTAS Device trigger state DCAS Device clear state Table 5 3 GPIB Error Conditions Numeric Symbolic Value n Value s Description NGER No GPIB error condition to report ECIC Command requires GPIB 232CT to be CIC ENOL Write detected no Listeners EADR GPIB 232CT not addressed correctly EARG Invalid argument or arguments ESAC Command requires GPIB 232CT to be SC 6 EABO T O operation aborted 7 10 Reserved 11 ECAP No capability for operation continues National Instruments Corp 5 49 GPIB 232CT User Manual S Mode Functions Chapter 5 Table 5 3 GPIB Error Conditions continued Numeric Symbolic Value n Value s Description 12 16 Reserved 17 ECMD Unrecognized command Table 5 4 Serial Port Error Conditions Numeric Symbolic Value n Value s Description 0 NSER No serial port error condition to report 1 EPAR Serial port parity error 2 EORN Serial port overrun error 3 EOFL Serial port receive buffer overflow 4 EFRM Serial port framing error A detailed description of the conditions under which each bit in status is set or cleared can be found in Appendix B In general the GPIB 232CT updates the first three status variables at the end of each programming message It updates the fourth status variable count after a cmd rd or wr
167. ual G 2 National Instruments Corp Appendix G Setting Switches TE Figure G 3 S mode 8 data bits 1 stop bit no parity 9600 baud These default characteristics might be adequate for most applications However if you want to change any of the Apple IIc s serial port characteristics use the utility program described in Chapter 4 of the Apple IIc Owner s Manual Configure the Serial Port After changing the Apple IIc s serial port characteristics set the switches on the GPIB 232CT to match precisely See Chapter 3 of this manual for details on setting each switch As one final example if your computer is an IBM PC or compatible the serial port default characteristics are as follows e baud rate 300 e parity even e databits 7 e stop bits 1 If these defaults meet the needs of your application set the GPIB 232CT switches as shown in Figure G 4 ETT Figure G 4 S mode 7 data bits 1 stop bit even parity 300 baud National Instruments Corp G 3 GPIB 232CT User Manual Setting Switches Appendix G In many cases you will want to change the default characteristics of the serial port on the IBM PC You may want to run at a higher baud rate up to 19200 baud and you may want to send 8 bit data bytes for binary data that will be sent to the GPIB device To change the IBM PC s serial port default characteristics to 9600 baud and 8 data bits from within BASICA place the following BASIC statement at the beginning
168. vice Before rsp completes all devices are unaddressed The interpretation of each device s response other than the RQS bit is device specific For example the polled device might set a particular bit in the response byte to indicate that it has data to transfer and another bit to indicate a need for reprogramming Consult the device documentation for interpretation of the response byte GPIB 232CT User Manual 5 38 National Instruments Corp Chapter 5 See Also S Mode Functions Each device s serial poll response byte is returned as a numeric string giving the decimal value of the byte followed by lt CR gt and lt LF gt If a device does not respond in the timeout period the GPIB 232CT returns string 1 and records the EABO error The time limit is set to 1 10 second unless you called tmo to change it Each response corresponds directly to an address you specify therefore there are exactly as many lines of responses including 1 as the number of addresses you specify If you call rsp and the GPIB 232CT is not CIC it attempts to become CIC If it cannot become CIC it records the ECIC error Refer to Appendix B for more information If this is the first function you call that requires GPIB Controller capability and you have not disabled System Controller capability with rsc the GPIB 232CT sends Interface Clear IFC to make itself CIC It also asserts Remote Enable If you passed control to some other GPIB devic
169. with the device address as a parameter ppu sends the device the parallel poll unconfigure byte hex 70 binary 0111 0000 which sets U to 1 to disable the device from responding to a parallel poll To unconfigure all devices the Controller can call ppu with no arguments which sends PPU parallel poll unconfigure hex 15 S Mode Example A system has three line printers two tape drives one card reader and one PC on a system The PC uses a GPIB 232CT to communicate on the GPIB All other devices are GPIB devices The PC is designated to be Active Controller and all other devices recognize this Furthermore all devices will set their IST bit to 1 when they are busy and 0 when they are free National Instruments Corp F 3 GPIB 232CT User Manual Parallel Polling Appendix F The Active Controller configures the card reader at address 6 to respond positively on DIO line 4 which sets bit 3 of the response byte when free by sending the configuration byte 01100011 The S bit is set to 0 the value of bits 0 through 2 is 3 PPC 6 4 0 When a parallel poll is conducted one of two things will happen If the card reader is free bit 3 of the response byte will be 1 if it is busy bit 3 will be 0 When the device is free its IST bit is 0 and because this equals the value of the S bit the device asserts DIO line 4 The Active Controller configures all of the line printers to respond positively on DIO line 1 when busy In this case
170. xv GPIB 232CT User Manual Contents Step 4 Communicate with rd and wrt Functions eee eee eee eeeeeee H 4 Using an HP 7475A Plotter with an IBM PC owe H 5 Getting Ready to Program 0 eect eeeeeseeeeeeseeeeeees H 5 Programming Steps ccsseeseecceseeseeseeseeseeneeeeseeeeeees H 6 Step 1 stat Function ss cc H 6 Step 2 Serial Port Functions 0 H 6 Step 3 GPIB Initialization Functions H 6 Step 4 Communicate with rd and wrt Functions eee eee eee reece H 7 Programming a Tektronix 2445 Oscilloscope from an Apple Meini isco sess n Morse iets sexed betes Sees H 8 Getting Ready to Program 0 0 0 eee eeeeeeeeeeereeeeetees H 8 Programming Steps scseeescescecesseeseeteeeeneeseseeeeeees H 9 Step 1 stat Function ss cc H 9 Step 2 Serial Port Functions 0 0 0 H 9 Step 3 GPIB Initialization Functions H 9 Step 4 Communicate with rd and wrt Functions eee eee eee eeeeeee H 9 G Mode Sample Programs eee eeeeseeeseeeeeseeeeeeeeseenseenseees H 10 Using an HP 7475A Plotter with a GPIB Controller 0 0 0 0 H 11 Getting Ready to Program 000 0 eee eeeeseeeeeeeeeeees H 11 Programming Steps scsseeseececeeteeseeseeeeneesesseeeeees H 12 Step 1 stat Function eeeeeeeeee H 12 Step 2 GPIB Initialization Functions H 12 Step 3 Serial Port Initialization Functions cc ceeeeeeeeeeeeeeeee H 12 Step 4 Communicate with Plotter H 13 IBM PC with GP

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