IOtech 488 quick reference guide

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GPIB-488

GPIB-488 Programming Reference Manual

Programming Reference Manual
July 2006 371930C-01
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© Copyright 1996-2006 by Measurement Computing Corporation’s licensor(s). All rights reserved.
Support
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Conventions

[ ] Square brackets indicate the key to be pressed.
» The » symbol leads you through nested menu items and dialog box options
to a final action. The sequence File»Page Setup»Options directs you to pull down the File menu, select the Page Setup item, and select Options from the last dialog box.
This icon denotes a note, which alerts you to important information.
This icon denotes a caution, which advises you of precautions to take to avoid injury, data loss, or a system crash.
When symbol is marked on a product, it denotes a warning advising you to take precautions to avoid electrical shock.
When symbol is marked on a product, it denotes a component that may be hot. Touching this component may result in bodily injury.
bold Bold text denotes items that you must select or click in the software, such
as menu items and dialog box options. Bold text also denotes parameter names.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. Italic text also denotes text that is a placeholder for a word or value that you must supply.
monospace Text in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples. This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions, operations, variables, filenames, and extensions.
GPIB terms used within this manual are:
GPIB General Purpose Interface Bus
System controller The system controller has the unique ability to retrieve active control of the
bus or to enable devices to be remotely programmed. It takes control of the bus by issuing an IFC (Interface Clear) message for at least 200 µsec. It also can put devices into the remote state by asserting the REN (Remote Enable) line.
There is always one system controller in a GPIB system. The system
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controller is designated at system initialization either through the use of hardware switches or by some type of configuration software, and is not changed. The system controller can be the same controller as the one which is the current active controller or an entirely different one. Note that if a controller is both a system controller and the active controller and it passes control to another controller, the system controller capability is not passed along with it.
Active controller The active controller is the controller which has the ability to mediate all
communications which occur over the bus. In other words, the active controller designates (addresses) which device is to talk and which devices are to listen. The active controller is also capable of relinquishing its position as active controller and designating another controller to become the active controller.
Device A device is any IEEE-488 instrument which is not a system controller or
active controller. It can be idle or act as a talker and/or listener when addressed or unaddressed by the active controller.
Listener A listener is any device which is able to receive data when properly
addressed. There can be up to 14 active listeners on the bus concurrently. Some devices can also be a talker or controller; however, only one of these functions can be performed at a time.
Talker A talker is a device which can transmit data over the bus when properly
addressed. Only one device can transmit at a time. Some devices can also be a listener or controller; however, only one of these functions can be performed at a time.
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Contents

Chapter 1 GPIB Software Overview
Supported Languages.....................................................................................................1-1
GPIB Library Utility Programs......................................................................................1-2
Support For VISA Calls ..................................................................................1-2
GPIB-32.DLL function support.......................................................................1-2
ibnotify ............................................................................................................1-2
Chapter 2 Programming with the GPIB Library
General Concepts...........................................................................................................2-2
Device vs. Board I/O .......................................................................................2-2
Device I/O .......................................................................................................2-2
Board l/O .........................................................................................................2-3
Device Handles................................................................................................2-3
Global Variables ...............................................................................2-4
iberr—The Error Variable.................................................................2-4
ibcnt and ibcntl—Count Variables....................................................2-4
Chapter 3 GPIB 488.1 Library Reference
IBASK ...........................................................................................................................3-3
IBCAC ...........................................................................................................................3-6
IBCLR............................................................................................................................3-7
IBCMD ..........................................................................................................................3-8
IBCMDA .......................................................................................................................3-10
IBCONFIG..................................................................................................................... 3-11
IBDEV ...........................................................................................................................3-15
IBDMA ..........................................................................................................................3-17
IBEOS............................................................................................................................3-18
IBEOT............................................................................................................................3-20
IBFIND ..........................................................................................................................3-21
IBGTS............................................................................................................................3-22
IBIST .............................................................................................................................3-24
IBLINES ........................................................................................................................3-25
IBLN ..............................................................................................................................3-27
IBLOC ...........................................................................................................................3-28
IBONL ...........................................................................................................................3-29
GPIB-488 v Programming Reference Manual
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Contents
IBPAD ...........................................................................................................................3-30
IBPCT............................................................................................................................3-31
IBPPC............................................................................................................................ 3-32
IBRD.............................................................................................................................. 3-34
IBRDA...........................................................................................................................3-36
IBRDF ...........................................................................................................................3-37
IBRPP............................................................................................................................ 3-39
IBRSC............................................................................................................................ 3-40
IBRSP............................................................................................................................ 3-41
IBRSV ...........................................................................................................................3-42
IBSAD ...........................................................................................................................3-43
IBSIC............................................................................................................................. 3-44
IBSRE............................................................................................................................3-45
IBSTOP ......................................................................................................................... 3-46
IBTMO .......................................................................................................................... 3-47
IBTRG ...........................................................................................................................3-49
IBWAIT......................................................................................................................... 3-50
IBWRT .......................................................................................................................... 3-52
IBWRTA ....................................................................................................................... 3-54
IBWRTF........................................................................................................................ 3-55
Chapter 4 GPIB 488.2 Library Reference
AllSpoll.......................................................................................................................... 4-2
DevClear........................................................................................................................4-3
DevClearList.................................................................................................................. 4-4
EnableLocal................................................................................................................... 4-5
EnableRemote................................................................................................................ 4-6
FindLstn......................................................................................................................... 4-7
FindRQS........................................................................................................................ 4-8
PassControl.................................................................................................................... 4-9
Ppoll............................................................................................................................... 4-10
PPollConfig ................................................................................................................... 4-11
PPollUnconfig ............................................................................................................... 4-12
RcvRespMsg.................................................................................................................. 4-13
ReadStatusByte.............................................................................................................. 4-14
Receive .......................................................................................................................... 4-15
ReceiveSetup ................................................................................................................. 4-16
ResetSys ........................................................................................................................4-17
Send ...............................................................................................................................4-18
SendCmds...................................................................................................................... 4-19
SendDataBytes .............................................................................................................. 4-20
SendIFC.........................................................................................................................4-21
Programming Reference Manual vi GPIB-488
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SendList .........................................................................................................................4-22
SendLLO........................................................................................................................4-23
SendSetup ......................................................................................................................4-24
SetRWLS .......................................................................................................................4-25
TestSRQ.........................................................................................................................4-26
TestSys...........................................................................................................................4-27
Trigger ...........................................................................................................................4-28
TriggerList .....................................................................................................................4-29
WaitSRQ........................................................................................................................4-30
Appendix A Multiline Interface Messages
Appendix B IBSTA
Appendix C IBERR
Contents
GPIB-488 vii Programming Reference Manual
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GPIB Software Overview
The GPIB software includes the 488.1 library, the 488.2 library, and a set of utility programs. The 488.1 library consists of all of the functions and subroutines that begin with the letters " to devices on the GPIB bus by their device names and handles rather than by their GPIB addresses.
The 488.2 library consists of all the routines that do not begin with the letters " bus by their GPIB addresses rather than by their names or handles.
Note The GPIB library is available only in a 32-bit version.

Supported Languages

The GPIB library provides identical routines for each supported language. Languages supported by the GPIB library at the time this manual was published are listed below.
ib". The 488.2 library routines refer to devices on the GPIB
1
ib". The 488.1 library routines refer

Table 1-1. Programming Languages

Programming Languages
Delphi
C
VB
GPIB-488 1-1 Programming Reference Manual
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Chapter 1 GPIB Software Overview

GPIB Library Utility Programs

The following utility programs are installed with the GPIB library software.
Utility program Description
GPIBDIAGNOSTIC.EXE
GPIBINTERACTIVECONTROL.EXE
GPIBCONFIGURATION.EXE

Support For VISA Calls

VISA (Virtual Instrument Software Architecture) drivers are command drivers that convert company and program-independent VISA calls into company-dependent calls.

GPIB-32.DLL function support

Each library function defined by GPIB 488.1 and GPIB 488.2 has a corresponding entry point in

ibnotify

The GPIB library does not support ibnotify. Applications that utilize the
ibnotify function will not run properly.
Hardware test program (Win32)
Interactive control program (Win32)
Configuration utility program (Win 32)
gpib-32.DLL.
Programming Reference Manual 1-2 GPIB-488
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Programming with the GPIB Library
The GPIB library contains two different and complete GPIB libraries.
Original 488.1 library—The 488.1 library (also referred to as the original library), consists of all of the functions and subroutines that begin with the letters " than GPIB addresses when referring to GPIB devices. There are two advantages to this approach:
The GPIB addresses of each device are not stored in the program, so
The program can refer to each device with an intelligible name rather
488.2 library—This library consists of all the routines that do not begin
with the letters " GPIB addresses rather than by names. The Device I/O section does not apply to the 488.2 library.
ib". This library uses a concept of device names and handles rather
the same program can run on different buses where the addresses of each device are different.
than a number (the GPIB address).
ib". These routines refer to all devices on the bus by their
2
The GPIB library includes different routines that allow you to control the operations of the GPIB bus in a very specific manner. You may find the number of routines included in the GPIB library intimidating, however, in most applications you need to use only a small subset of these routines.
The routines are divided into two distinct libraries. All routines which begin with "
ib" are part of the "488.1" or "Original GPIB library." All other
routines are part of the "488.2 library." You only need to use one or the other library. Each library provides a different method of performing the same tasks. The choice of which library to use is a matter of personal preference. If you use the original GPIB library, you can perform either Board Level or Device Level operations.
GPIB-488 2-1 Programming Reference Manual
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Chapter 2 Programming with the GPIB Library

General Concepts

This section explains the difference between routines which use Device I/O and those which use Board I/O, the use of device handles, and the global variables used by the library routines.

Device vs. Board I/O

The most typical GPIB operations are sending commands to a device attached to the bus and reading back responses. To do this, program the GPIB board to execute these steps:
1. Address the selected device as a Listener.
2. Send the secondary address if used.
3. Address the board itself as the GPIB Talker.
4. Send the command bytes to the device.
5. Address the board itself as the Listener.
6. Read the response from the device.
7. Send the GPIB Unlisten (UNL) message.
8. Send the GPIB Untalk (UNT) message.
The original GPIB library interface is comprised of two different types of routines: Board I/O and Device I/O. These routines are described in Chapter 3, GPIB 488.1 Library Reference. You can program the board using either Board I/O routines or Device I/O routines to perform the sequence of operations outlined above.
The 488.2 library is all "Board I/O" in that you always supply the board ID and the device address. Refer to Chapter 4, GPIB 488.2 Library Reference.

Device I/O

It is usually easier to use the Device I/O routines. Device I/O is very simple to use and understand. Device I/O routines are higher-level routines which conceal most of the underlying complexity of GPIB operations. The Device I/O routines automatically take care of all of the low-level details involving GPIB messages and addressing. For example, to accomplish the seven steps listed above, you use only three routines:
ibdev—to open the device
ibwrt—to send the instrument command
ibrd—to read the data back from the device
Programming Reference Manual 2-2 GPIB-488
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Board l/O

Chapter 2 Programming with the GPIB Library
In comparison, the Board I/O routines are low-level routines. If you use them, you must understand how the GPIB operates in detail. Generally, the only time you need to use Board I/O is if it is impossible to perform the same operation using device I/O, such as passing control from one controller to another.
To perform the same task as the seven steps outlined in Device vs. Board
I/O (send a command to a device), you need to know the codes for the
various forms of addressing and the codes for the GPIB Unlisten and Untalk commands.
Use the routines in this sequence:
ibfind—to open the board
ibcmd—to send the address of the talker and listener
ibwrt—to send the command to the device
ibcmd—to send the address of the talker and listener
ibrd—to read the data back from the device
ibcmd—to send the Unlisten (UNL) and Untalk (UNT) commands

Device Handles

Most of the routines in the 488.1 library have a device handle as the first argument. The first GPIB call in your program is usually routine "opens" a board or device and returns a GPIB board or device handle. If you pass the name of a board, it returns a board handle. Likewise, if a device name is passed, a device handle is returned. Some library routines only work with device handles, some only with board handles, and some with both.
GPIB-488 2-3 Programming Reference Manual
ibfind. This
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Chapter 2 Programming with the GPIB Library
Global Variables
The following global variables are used in all programming languages:
ibsta Status Word
iberr Error Codes
ibcnt, ibcntl Count Variables (short/long)
The
iberr variables are briefly explained here. For additional information
about
iberr, refer to Appendix C, IBERR.
For additional information about
ibcnt and ibcntl, refer to the routines
which return them.
iberr—The Error Variable
If a GPIB error occurs during a routine, its corresponding error code is returned into the variable
iberr. Possible error codes and their meanings
are listed in Appendix C, IBERR.
ibcnt and ibcntl—Count Variables
These variables contain an integer which describes how many bytes were actually transferred during a read or write operation. value (16-bits wide) and
ibcntl is a long integer value (32-bits wide).
ibcnt is an integer
Programming Reference Manual 2-4 GPIB-488
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GPIB 488.1 Library Reference
This chapter describes each of the 488.1 GPIB library routines. A short description of the routine, its syntax, parameters, any values that are returned, any special usage notes, and an example are included for each routine. The routines are listed in alphabetical order. The following table lists all of the 488.1 GPIB library routines. A full description of each routine follows the table.

Table 3-1. 488.1 Library routines

Name Description
3
ibask
ibcac
ibclr
ibcmd
ibcmda
ibconfig
ibdev
ibdma
ibeos
ibeot
ibfind
ibgts
ibist
iblines
ibln
ibloc
Returns software configuration information
Become Active Controller
Clear specified device
Send GPIB commands from a string
Send GPIB commands asynchronously from a string
Configure the driver
Open and initialize a device when the device name is unknown
Enable/Disable DMA
Change EOS
Change EOI
Open a device and return its unit descriptor
Go from Active Controller to standby
Define IST bit
Return status of GPIB bus lines
Check for presence of device on bus
Go to Local
ibonl
GPIB-488 3-1 Programming Reference Manual
Place device online/offline
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Chapter 3 GPIB 488.1 Library Reference
Table 3-1. 488.1 Library routines (Continued)
Name Description
ibpad
ibpct
ibppc
ibrd
ibrda
ibrdf
ibrpp
ibrsc
ibrsp
ibrsv
ibsad
ibsic
ibsre
ibstop
ibtmo
ibtrg
Change Primary address
Pass Control
Parallel Poll Configure
Read data to a string
Read data asynchronously
Read data to file
Conduct parallel poll
Request/release system control
Return serial poll byte
Request service
Define secondary address
Send IFC
Set/clear REN line
Stop asynchronous I/O operation
Define time limit
Trigger selected device
ibwait
ibwrt
ibwrta
ibwrtf
Programming Reference Manual 3-2 GPIB-488
Wait for event
Write data from a string
Write data asynchronously from a string
Write data from file
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IBASK

Returns software configuration information.
Syntax
C ibask (int boarddev, int option, unsigned int
Parameters
boarddev A board handle or device handle option Specifies which configuration item to return; see Table. value Current value of specified item returned here
Option Valid for Information returned
Chapter 3 GPIB 488.1 Library Reference
*value)

Table 3-2. ibask Options

IbaPAD bd/dev
IbaSAD bd/dev
IbaTMO bd/dev
IbaEOT bd/dev
IbaPPC bd
IbaREADDR dev
IbaAUTOPOLL bd
IbaCICPROT bd
IbaSC bd
IbaSRE bd
Primary address of board or device
Secondary address of board or dev
The current timeout value for I/O commands (refer to ibtmo for a list of possible values)
0 = EOI asserted at end of write
non zero = EOI is not asserted at end of write
The current parallel poll configuration of the board
0 = Forced re-addressing is disabled
non zero = Forced re-addressing is enabled.
0 = automatic at end of write
non zero = automatic serial poll is disabled
0 = CIC protocol is disabled
non zero = CIC protocol is enabled
0 = board is not system controller
non zero = board is system controller
0 = do not automatically assert REN line when system controller
non zero = automatically assert REN line when system controller
GPIB-488 3-3 Programming Reference Manual
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Chapter 3 GPIB 488.1 Library Reference
Table 3-2. ibask Options (Continued)
Option Valid for Information returned
IbaEOSrd bd/dev
IbaEOSwrt bd/dev
IbaEOScmp bd/dev
IbaEOSchar bd/dev
IbaPP2 bd
IbaTiming bd
IbaDMA bd
IbaSendLLO bd
IbaSPollTime dev
0 = ignore EOS char during reads
non zero = terminate read when EOS char is received
0 = don’t assert EOI line when EOS char is sent
non zero = assert EOI line whenever EOS char is sent
0 = 7 bit compare is used when checking for EOS char
non zero = 8 bit compare is used when checking for EOS char
0 = The current EOS char of board or device
0 = board is in remote parallel poll configuration
non zero = board is in local parallel poll configuration
Current T1 timing delay 1 = Normal (2 us), 2 = High Speed (500 ns), 3 = Very High Speed (350 ns)
0 = The interface does not use DMA for GPIB transfers
non zero = The interface uses DMA for GPIB transfers
0 = LLO command is not sent when device is put online
non zero = LLO command is sent
Length of time to wait for parallel poll response before timing out
IbaPPollTime bd
IbaEndBitIsNormal bd
Length of time to wait for parallel port response
0 = The END bit of ibsta is not set when the EOS character is received without EOI.
non zero = The END bit of ibsta is set when the EOS character is received
IbaUnAddr dev
0 = The untalk and unlisten (UNT, UNL) are not sent after each device level read/write
non zero = The UNT, UNL commands are sent after each device lever read/write
IbaIST bd
IbaBNA dev
Programming Reference Manual 3-4 GPIB-488
The individual status (ist) bit of the interface
Device’s access board
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Chapter 3 GPIB 488.1 Library Reference
Returns ibsta will contain a 16-bit status word; refer to Appendix B,
IBSTA.
iberr will contain an error code if an error occurred value will contain the current value of selected configuration
item
Usage notes Some options apply to boards, some to devices and some apply to
both boards and devices. A program may modify many of these configuration items via library routines (for example,
ibask returns the modified version.
Example Returns the
C int dev, istbit;
dev = ibdev (0,3,0,13,1,0); ibask (dev, IbaIST, &istbit);
ist bit of a device at PAD 3.
ibtmo, ibeos, etc.). In that case,
GPIB-488 3-5 Programming Reference Manual
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Chapter 3 GPIB 488.1 Library Reference

IBCAC

Makes the specified board the Active Controller.
Syntax
C ibcac (int board, int sync)
Parameters
board is an integer containing the board handle
sync specifies if the GPIB board is to take control synchronously or asynchronously. If sync
is 0, the GPIB board takes control asynchronously. Otherwise, it takes control synchronously (immediately).
When the board takes control, the GPIB interface board asserts the ATN line. When taking control synchronously, the board waits for any data transfer to be completed and then takes control. Note that if synchronous take control is specified while an is in progress, the synchronous take control may not occur if a timeout or other error occurs during the
In comparison, if the board is to take control asynchronously, it takes control immediately, without waiting for any data transfers to be completed.
ibrd/ibwrt.
ibrd or ibwrt operation
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. In particular, the ECIC error occurs if
the specified GPIB board cannot become an Active Controller.
Usage Notes
This routine is only used when doing board level I/O.
Example
GPIB board 1 takes control asynchronously.
C ibcac (brd1, 0);
Programming Reference Manual 3-6 GPIB-488
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IBCLR

Clears a specified device.
Syntax
C ibclr (int device)
Parameters
device is an integer containing the device handle.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the GPIB Interface Board (which is currently the CIC) sends its talk address over the GPIB. This makes it the active talker. It then unlistens all devices and addresses the specified device as a listener. Finally, the GPIB board clears the device, by sending the
Chapter 3 GPIB 488.1 Library Reference
Selected Device Clear message.
Example
This example uses ibdev to return the unit descriptor for a device at PAD 5, a DMM, into the variable dmm. The DMM is then cleared.
C int dmm;
dmm = ibdev(0,5,0,13,1,0);
/*open instrument*/
ibclr (dmm);
/* clear it */
GPIB-488 3-7 Programming Reference Manual
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Chapter 3 GPIB 488.1 Library Reference

IBCMD

Sends GPIB commands.
Syntax
C ibcmd (int board, char cmnd[], long bytecount)
Parameters
board is an integer containing the board handle.
cmnd is the command string to be sent. This string is comprised of GPIB multiline commands.
These commands are listed in Appendix A, Multiline Interface Messages.
bytecount is the number of command bytes to be transferred.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
ibcnt, ibcntl will contain the number of bytes that were transferred. ibcnt is a 16-bit
integer. instead of
ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl
ibcnt.
Usage Notes
This routine passes only GPIB commands. It cannot be used to transmit programming instructions (data) to devices. Use the
This routine terminates when any one of the following takes place:
Commands transfer is successfully completed.
An error occurs
A timeout occurs
A Take Control (TCT) command is sent
The system controller asserts the IFC (Interface Clear) line.
Programming Reference Manual 3-8 GPIB-488
ibrd and ibwrt routines for this purpose.
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Example
Chapter 3 GPIB 488.1 Library Reference
This example prepares the board to talk and addresses three devices (at addresses 8, 9, and
10) to listen.
C char *command;
command = "\0x3f\0x5f\0x40\0x28\0x29\0x2a" ibcmd (board, command, 6);
GPIB-488 3-9 Programming Reference Manual
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Chapter 3 GPIB 488.1 Library Reference

IBCMDA

Transfers GPIB commands asynchronously from a string.
Syntax
C ibcmda (int board, char cmnd[], long bytecount)
Parameters
board is an integer containing the board handle.
cmnd is thecommand string to be sent. This string is comprised of GPIB multiline
commands.These commands are listed in Appendix A, Multiline Interface Messages.
bytecount is the number of command bytes to be transferred. Note that in C, although this
parameter is of type long, integer values and variables can also be passed.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. An ECIC error is generated if the GPIB
Interface Board specified is not the Active Controller. If no listening devices are found, the ENOL error is returned.
ibcnt, ibcntl will contain the number of bytes that were transferred. ibcnt is a 16-bit
integer. instead of
ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl
ibcnt.
Usage Notes
This routine passes only commands. It is not used to transmit programming instructions (data) to devices. Use the
ibrd/ibwrt routines for this purpose.
Asynchronous I/O is not explicitly supported and will be treated as synchronous.
Example
This example prepares the board to talk and addresses three devices (at addresses 8, 9, and
10) to listen. loop. This loop calls completed or an error has occurred. The program may do anything within the WHILE loop except make other GPIB I/O calls.
C char command[] = "\0x3f\0x5f\0x40\0x28\0x29\0x2a"
Programming Reference Manual 3-10 GPIB-488
ibcmda executes in the background and the program continues into the WHILE
ibwait to update ibsta and checks ibsta to see if ibcmda has
ibcmda (board, command, 6); while ( (ibsta & CMPL+ERR) == 0)
ibwait (board, 0);
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IBCONFIG

Changes configuration parameters.
Syntax
C ibconfig (int boarddev, unsigned int option,
Parameters
boarddev is an integer containing either a board handle or device handle.
option is a number which represents the configuration option to be changed. See Table 3-3.
value is the new configuration option value. Allowed values differ according to the option
being programmed.
Option Valid for Description
Chapter 3 GPIB 488.1 Library Reference
unsigned int value)

Table 3-3. ibconfig Options

IbcPAD bd or dev
IbcSAD bd or dev
IbcTMO bd or dev
IbcEOT bd or dev
IbcPPC bd
IbcREADDR dev
New Primary Address. Available primary addresses range from 0 to 30. (See
ibpad.)
value can be from 0 to 30 decimal.
New Secondary Address. There are 31 secondary addresses available. decimal. (See
value can be 0 or from 96 to 126
ibsad.)
Timeout Value. The approximate time that I/O functions take before a timeout occurs.
value is a
number from 0 to 15 which corresponds to timeout values ranging from 10 usec to 100 sec. (See ibtmo)
Enable/disable END message. If this option is enabled, the EOI line is asserted when the last byte of data is sent. If
value = 0, then the EOI line is not asserted. If value
is non zero, the EOI line is asserted.
Parallel Poll Configure. Redefines the parallel poll configuration bytes.
value can be 0, or from 96 to 126
decimal.
Forced re-addressing. If value = 0, forced re-addressing is disabled
non zero = Forced re-addressing is enabled.
GPIB-488 3-11 Programming Reference Manual
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Chapter 3 GPIB 488.1 Library Reference
Table 3-3. ibconfig Options (Continued)
Option Valid for Description
IbcAUTOPOLL bd
IbcCICPROT bd
IbcIRQ bd
IbcSC bd
IbcSRE bd
IbcEOSrd bd or dev
IbcEOSwrt bd or dev
Enable/Disable Automatic Serial Polling. If value is 0, then Automatic Serial Polling is disabled. Otherwise, it is enabled.
CIC Protocol. If value is 0, then CIC Protocol is not used. Otherwise, CIC Protocol is used.
Enable/Disable Hardware Interrupts. If value is 0, then hardware interrupts are disabled, otherwise
value
specifies the IRQ level the board uses to generate interrupts.
Request/Release System Control. If value is 0, the board is not able to support routines requiring system controller capability.
If value is non-zero, the board can support routines requiring system controller capability.
Assert/Unassert REN. If value is 0, the REN line is unasserted. Otherwise, the REN line is asserted.
Recognize EOS. If value is non-zero, a read is terminated when the End-Of-String (EOS) character is detected. Otherwise, EOS detection is disabled.
Assert EOI. If value is non-zero, then EOI is asserted when the EOS character is sent. Otherwise, EOI is not asserted.
IbcEOScmp bd or dev
7/8-bit Comparison. If value is zero, compare the low-order 7 bits of the EOS character. Otherwise, compare 8-bits.
IbcEOSchar bd or dev
IbcPP2
End-Of-String (EOS) Character. value is the new EOS character.
value can be any 8-bit value.
Parallel Poll Remote/Local. If value is zero, then the GPIB Interface Board is remotely configured for a parallel poll by an external Controller. Otherwise, the GPIB interface board accepts parallel poll configuration commands from your application program.
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Chapter 3 GPIB 488.1 Library Reference
Table 3-3. ibconfig Options (Continued)
Option Valid for Description
IbcTIMING bd
IbcDMA bd
IbcSendLLO bd
IbcSPollTime bd or dev
IbcEndBitIsNormal bd or dev
IbcPPollTime bd
IbcUnAddr dev
Handshake Timing. If value is 1, normal timing (> 2 *sec.) is used. If nsec.) is used. If
value is 2, high-speed timing (> 500
value is 3, very high-speed timing (>
350 nsec.) is used.
Enable/Disable DMA. If value is zero, DMA transfers are disabled, otherwise
value specifies the DMA
channel that the board uses.
Send Local Lockout. If value is 0, LLO command is not sent when device is put online; non zero = LLO command is sent
Serial Poll Timeout. value ranges from 0 to 17 specify timeouts of 10 msecs to 1000 secs. Refer to Table 3-6,
Timeout Codes.
If set, causes END status to be set on receipt of EOS.
Parallel Poll Timeout. value ranges from 0 to 17 specify timeouts of 10 msecs to 1000 secs. Refer to Table 3-6, Timeout Codes.
If value is 0, the untalk and unlisten (UNT, UNL) are not sent after each device level read/write; non zero = the UNT, UNL commands are sent after each device lever read/write
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
None.
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Chapter 3 GPIB 488.1 Library Reference
Example
This example illustrates how to change the timeout value for GPIB Interface Board 1 to 300 msec.
C int device;
device = ibfind ("gpib1"); ibconfig (device, IbcTMO, 10);
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IBDEV

Obtains a device handle for a device whose name is unknown. It opens and initializes the device with the configuration given.
Syntax
C device = ibdev (int boardindex, int pad, int sad,
Parameters
boardindex identifies the GPIB Interface Board with which the device descriptor is
associated. It is an index in the range 0 to (total number of boards - 1).
pad is the primary address of the device. Available addresses range from 0 to 30.
sad is the secondary address of the device. There are 31 secondary addresses available. value
can be 0, or from 96 to 126 decimal; see Appendix A, Multiline Interface Messages. If 0 is selected, the driver will not expect the device to require a secondary address.
timeout is the timeout of the device. This is a value from 0 to 17 which corresponds to
timeout value ranging from 10 usec to 1000 sec. See Table 3-6, Timeout Codes, for a list of timeouts and corresponding values.
Chapter 3 GPIB 488.1 Library Reference
int timeout, int eot, int eos)
eot when writing to a device, eot specifies whether or not to assert EOI with the last data byte.
If eot is non-zero, EOI is asserted. If eot is 0, EOI is not asserted.
eos specifies the End-Of-String termination mode to be used when communicating with the
device. See Table 3-4, Selecting EOS, for a description of special formatting features of this argument.
Returns
device will contain the assigned descriptor or a negative number. If device is a negative
number, then an error occurred. Two types of errors can occur:
•An
EDVR or ENEB error is returned if a device is not available or the board index specifies
a non-existent board.
•An
iberr will contain an error code, if an error occurred.
EARG error is returned if illegal values are given for pad, sad, timeout, eot, eos.
Usage Notes
This routine returns the device handle of the first available user-configurable device it finds in the device list.
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Example
This example opens an available device, associates it with GPIB interface board 1, and assigns it the following device configuration parameters.
primary address = 3
secondary address = 19 (115 decimal, 73 hex)
timeout = 10 sec
Assert EOI
EOS Disabled
The new device handle is returned.
C int device;
device = ibdev(1, 3, 0x73, 13, 1, 0);
Programming Reference Manual 3-16 GPIB-488
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IBDMA

Enables/Disables DMA.
Syntax
C ibdma (int board, int dma)
Parameters
board is an integer containing the board handle.
dma is an integer which indicates whether DMA is to be enabled or disabled for the specified
GPIB board. If memory are performed using DMA. Otherwise, programmed I/O is used.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. An ECAP error results if you tried to
enable DMA operations for a board which does not support DMA operation. If no error occured, the previous value of
Chapter 3 GPIB 488.1 Library Reference
dma is non-zero, all read and write operations between the GPIB board and
dma is stored in iberr.
Usage Notes
The GPIB Interface Board must have been configured for DMA operations in order for this routine to be executed successfully. This routine is useful for alternating between programmed I/O and DMA operations. This call remains in effect until one of the following occurs:
Another
The program is re-started.
The maximum DMA transfer length in Windows is 64 K bytes.
Example
C int board, ibsta;
ibdma call is made.
ibonl or ibfind is called.
This example enables DMA transfers for GPIB Interface Board 1. It assumes that the DMA channel was previously selected in your configuration program.
board = ibfind ("gpib1"); ibsta = ibdma (board, 1);
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Chapter 3 GPIB 488.1 Library Reference

IBEOS

Changes or disables End-Of-String termination mode.
Syntax
C ibeos (int boarddev, int eos)
Parameters
boarddev is an integer containing the board/device handle.
eos is an integer that defines which termination mode and what EOS character are to be used,
as shown in Table 3-4, Selecting EOS.

Table 3-4. Selecting EOS

eos
Method Description
A Terminate read when EOS is detected. Can be used
alone or in combination with Method C. (Constant = REOS)
B Set EOI with EOS on write function. Can be used alone
or in combination with Method C. (Constant = XEOS)
C Compare all 8 bits of EOS byte rather than low 7 bits for
all read and write functions. (Constant = BIN)
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. If an error does not occur the previous
value of
eos is stored in iberr.
Usage Notes
This call only defines an EOS byte for a board or device. It does not cause the handler to automatically send that byte when performing writes. Your application must include the EOS byte in the data string it defines.
If this call defines an EOS for a device, then the defined EOS is used for all reads and writes involving that device. Likewise, if the call defines an EOS for a board, then all reads and writes involving that board will use that EOS.
High Byte Low Byte
00000100 EOS
character
00001000 EOS
character
00010000 EOS
character
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Chapter 3 GPIB 488.1 Library Reference
This call remains in effect until one of the following occurs:
Another
ibonl or ibfind is called.
ibeos call is made.
The system is re-started.
Example
See also
ibeot
This example configures the GPIB system to send the END message whenever the line feed character is sent to a particular device. Method B described in Table 3-4, Selecting EOS, is used (
XEOS).
C int device;
ibeos (device, XEOS + '\n');
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Chapter 3 GPIB 488.1 Library Reference

IBEOT

Enables/Disables assertion of EOI on write operations.
Syntax
C ibeot (int boarddev, int eot)
Parameters
boarddev is an integer containing the board or device handle. Here it represents a GPIB
Interface Board or a device. This value is obtained by calling the
eot is an integer which defines whether or not EOI is to be asserted. If eot is non-zero then
EOI is asserted automatically when the last byte of the message is sent. If is not asserted.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This call is used to temporarily change the default EOT setting.
ibfind routine.
eot is 0, then EOI
It is useful to automatically send EOI with the last data byte in situations where variable length data is being sent. When EOI is enabled, you do not need to send an EOS character.
If this call specifies a device, then EOI is asserted/unasserted on all writes to that device. Likewise, if the call specifies a board, then EOI is asserted/unasserted on all writes from that board. To assert EOI with an EOS, use the
ibeos routine. This call remains in effect until one
of the following occurs:
Another ibeot call is made.
ibonl or ibfind is called.
The system is re-started.
See also ibeos
Example
Assert EOI with last byte of all write operations from GPIB board 1.
C int device;
device = ibfind ("gpib1"); ibeot (device,1);
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IBFIND

Opens a board or device and returns the handle associated with a given name.
Syntax
C boarddev = ibfind (char name[])
Parameters
name is the string specifying the board or device name.
Returns
boarddev will contain the device handle associated with the given name. If a negative
number is returned, this indicates that the call has failed. This most often happens when the specified name is does not match the default/configured board or device name.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This call is also opens the device/board and initializes the software parameters to their default configuration settings. See
Chapter 3 GPIB 488.1 Library Reference
ibonl.
Using
ibfind to obtain device descriptors is useful only for compatibility with existing
applications. New applications should use
ibdev instead of ibfind.
Example
This example returns the device handle associated with the device named "DEV5" to the variable
C Board = ibfind("GPIB0");
GPIB-488 3-21 Programming Reference Manual
dmm. If the device name is not found, the program will jump to an error routine.
if (Board < 0) error();
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Chapter 3 GPIB 488.1 Library Reference

IBGTS

Puts an Active Controller in Standby mode.
Syntax
C ibgts (int board, int handshake)
Parameters
board is an integer containing the board handle.
handshake determines whether or not the shadow handshake option is to be activated. If handshake is non-zero, then the GPIB shadow handshake option is activated. This means
that the GPIB board shadow handshakes the data transfer as an acceptor and when the END message is detected, the GPIB board enters a hold-off state on the GPIB. Thus, the GPIB board participates in the data handshake as an Acceptor without actually reading the data. It monitors the transfers for the holds off subsequent transfers. Using this mechanism, the GPIB board can take control synchronously on a subsequent operation like
If
handshake is 0, then no shadow handshake or holdoff is done.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
Not Ready For Data (NRFD) handshake
END message and
ibcmd or ibrpp.
iberr will contain an error code, if an error occurred. The ECIC error occurs if the board is
not an Active Controller.
Usage Notes
This call makes the GPIB board go to Controller Standby state and unasserts the ATN line if it is initially the Active Controller. This allows transfers between GPIB devices to occur without the GPIB board's intervention.
Before performing an
ibgts with a shadow handshake, use the ibeos function to
define/disable EOS character detection.
Example
This example uses the ibcmd routine to instruct GPIB board 1 to unlisten all devices (ASCII ?, hex 3F), and then to address a Talker at MTA26 (ASCII Z, hex 5) and a Listener at MLA11 (ASCII +, hex 2B). then called to unassert the ATN line and place the GPIB board in Standby mode. This action allows the Talker to send messages to the Listener. Note that the GPIB commands/addresses are coded using printable ASCII characters, for example, "?Z+".
Programming Reference Manual 3-22 GPIB-488
ibgts is
Page 36
C int gpib1;
gpib1 = ibfind ("GPIB1"); ibcmd (gpib1, "?Z+", 3); ibgts (gpib1, 1);
Chapter 3 GPIB 488.1 Library Reference
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Chapter 3 GPIB 488.1 Library Reference

IBIST

Sets/Clears the IST (Individual Status) Bit of the GPIB board for parallel polls.
Syntax
C ibist (int board, int statusbit)
Parameters
board is an integer containing the board handle.
statusbit indicates whether the IST bit is to be cleared or set. If statusbit is non-zero,
then the IST bit is set. Otherwise, if
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. If an error does not occur, the previous
IST value is stored in
Usage Notes
This routine is used when the GPIB Interface is not the Active Controller.
iberr.
statusbit = 0, the IST bit is cleared.
IST should be SET to indicate to the controller that service is required.
Example
This example clears GPIB Board 1's IST bit.
C int gpib1;
gpib1 = ibfind ("GPIB1"); ibist (gpib1, 0);
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Chapter 3 GPIB 488.1 Library Reference

IBLINES

Returns the status of the GPIB control lines.
Syntax
C iblines (int board, short *clines)
Parameters
board is an integer containing the board handle.
Returns
clines contains a valid mask and GPIB control line state data. Low-order bytes (bits 0
through 7) contain the mask indicating the capability of the GPIB interface board to sense the status of each GPIB control line. Upper bytes (bits 8 through 15) contain the GPIB control line state information. The pattern of each byte is as follows:
High
15 14 13 12 11 10 9 8
EOI AT N SRQ REN IFC NRFD NDAC DAV
7 6 5 4 3 2 1 0
Low (Mask)
To determine if a GPIB control line is asserted, first check the appropriate bit in the lower byte to determine if the line can be monitored (indicated by a 1 in the proper bit position), then check the corresponding bit in the upper byte. If the bit is set (1), the corresponding control line is asserted. If the bit is clear (0), the control line is unasserted.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Handshake Information:
NRFD = Not Ready for Data
NDAC = Not Data Accepted
DAV = Data Valid
Interface Management:
ATN = Attention
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IFC = Interface Clear
REN = Remote Enable
SRQ = Service Request
EOI = End or Identify
Usage Notes
In order for this call to function properly, all devices attached to the GPIB bus must adhere to IEEE-488 specification.
Example
This example tests the state of the ATN line.
C #define ATNLINE = 0x40
int lines; iblines (board, &lines); if (lines & ATNLINE == 0)
printf "ATN line can not be monitored by this GPIB board"; else ( (lines >> 8) & ATNLINE ) == 0)
printf "ATN line is not asserted";
Programming Reference Manual 3-26 GPIB-488
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IBLN

Check that a device is present on the bus.
Syntax
C ibln (int board, int pad, int sad, short* listen)
Parameters
board is the board or device handle.
pad is the primary address of the GPIB device (0-30).
sad is the secondary address of the GPIB device (96-126 or 0x60-0x7e) or one of the constant
values NO_SAD or ALL_SAD.
listen is the variable that the result is returned to.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code if an error occurred.
Chapter 3 GPIB 488.1 Library Reference
listen will contain 0 if no listener is found. Contains non-zero if a listener is found.
Usage Notes
Set sad = NO_SAD (0) if the device does not have a secondary address.
Set
sad = ALL_SAD (-1) if you do not know the device’s secondary address and you want
all possible secondary addresses to be tested.
Example
This example tests for the presence of a device with a GPIB address of 4.
C int board, listen;
board = ibfind (“GPIB0”); ibln (board, 4, NO_SAD, &listen);
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Chapter 3 GPIB 488.1 Library Reference

IBLOC

Forces the specified board/device to go to local program mode.
Syntax
C ibloc (int boarddev)
Parameters
boarddev is an integer containing the device or board handle.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine is used to place boards or devices temporarily in local mode. If this routine specifies a device, the following GPIB commands are sent:
Talk address of the access board
Secondary address of the access board
Unlisten (UNL)
Listen address of the device
Secondary address of the device (as necessary)
Go to Local (GTL)
If this routine specifies a board, the board is placed in a local state by sending the Return to Local (RTL) message, if it is not locked in remote mode. The LOK bit of the status word indicates whether the board is in a lockout state. The front panel RTL switch if the computer is used as an instrument.
IBLOC function is used to simulate a
Example
Return GPIB board 1 to local state.
C int gpib1;
gpib1 = ibfind("GPIB1"); ibloc (gpib1);
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IBONL

Enables/Disables a device/interface board for operation.
Syntax
C ibonl (int boarddev, int online)
Parameters
boarddev is an integer containing the device/board handle.
online defines whether the device/board is to be enabled/disabled. If online is non-zero,
the device/board is enabled for operation (placed on-line). This restores the board/device to its default settings. Otherwise, the board/device is placed off-line.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When a device is placed off-line, it is "closed". This means that in order to perform any other operations with this device, you will need to re-open it by calling the routine.
Chapter 3 GPIB 488.1 Library Reference
ibfind or ibdev
Example
This example restores the configuration of a device at PAD 1.
C int Dev;
Dev = ibdev (0,1,0,13,1,0); ibonl (Dev, 1);
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IBPAD

Changes the primary address assigned to a device or interface board.
Syntax
C ibpad (int boarddev, int address)
Parameters
boarddev is an integer containing the board or device handle.
address specifies the new primary GPIB address. Valid primary addresses range from 0 to
30 (0 to 1E hex).
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code if an error occurred. Contains the previous primary address
if no error occurred.
Usage Notes
This routine temporarily changes the configuration setting. It remains in effect until ibonl or
ibfind is called, ibpad is called again, or the system is re-started.
EARG error occurs if address is out of range.
If a device is specified, its talk and listen addresses are assigned on the basis of Listen Address equals
address + 20 hex. Its Talk Address equals address + 40 hex. Thus,
address. Its
if a primary address of 0D hex was specified, the corresponding Listen Address would be 2D hex (MLA 13) and Talk Address would be 4D hex (MTA 13). If a board is specified, the board is assigned the primary address defined by
address. Refer also to ibsad and IBONL.
Be sure that the address specified agrees with the GPIB address of the device. (Set with hardware switches or by a software program. Refer to the device's documentation for more information.)
Example
This example changes the primary GPIB address associated with a DVM at PAD 4 to 1C hex.
C int dvm;
dvm = ibdev (0,4,0,13,1,0); ibpad (dvm, 0x1C);
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IBPCT

Passes control to another device.
Syntax
C ibpct (int device)
Parameters
device an integer containing the device handle.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This makes the specified device the Controller-In-Charge (CIC). The GPIB board goes to the Controller Idle state and releases the ATN line.
The device that control is passed to must have Controller capability.
Chapter 3 GPIB 488.1 Library Reference
Example
This example makes a device at PAD 1 the Controller-In-Charge.
C int Dev;
Dev = ibdev (0,1,0,13,1,0); ibpct(Dev);
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IBPPC

Enables/Disables parallel polling of the specified device.
Syntax
C ibppc (int boarddev, int command)
Parameters
boarddev is an integer containing the board or device handle. This value is obtained by
calling the
command is a valid parallel poll enable/disable message or 0. If command represents a PPE
message, then the device will use that message to respond to a parallel poll. Valid PPE
messages range from 60 to 6F hex. The PPE specifies the GPIB data line (DIO1 through DIO8) on which the device is to respond and whether that line is to be asserted or unasserted.
The PPE byte is of the format:
7 6 5 4 3 2 1 0
ibfind routine.
0 1 1 0 SENSE P2 P1 P0
Where
SENSE indicates the condition under which the data line is to be asserted. The device
compares the value of the sense bit to its IST (individual status) bit and responds appropriately. For example, if SENSE = 1, the device will drive the line TRUE if its IST = 1 or FALSE if IST = 0.
P2–P0 specify which GPIB data line should be used to respond to a parallel poll, as shown in
Table 3-5.
Table 3-5. Values for P2–P0
P2 P1 P0 GPIB Data Line
1 1 1 DIO8
1 1 0 DIO7
1 0 1 DIO6
1 0 0 DIO5
0 1 1 DIO4
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Chapter 3 GPIB 488.1 Library Reference
Table 3-5. Values for P2–P0
P2 P1 P0 GPIB Data Line
0 1 0 DIO3
0 0 1 DIO2
0 0 0 DIO1
For example, if the PPE byte 01101011 (hex 6B) is sent, the device will drive DIO4 true if its IST bit = 1, or false if its IST bit = 0.
If
command is 0 or represents a PPD (Parallel Poll Disable) message, the current PPE
(Parallel Poll Enable) configuration is cancelled. Valid PPD messages range from 70 to 7F hex. The PPD is of a similar format to the PPE byte, for example:
7 6 5 4 3 2 1 0
0 1 1 0 SENSE P2 P1 P0
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. Contains the previous value of command if no error occurs.
Usage Notes
If boarddev specifies a GPIB interface board, this routine sets the board's Local Poll Enable (LPE) message to
If
boarddev specifies a device, the GPIB Interface Board associated with the device
command.
addresses itself as a Talker, unlistens all devices (sends a UNL), addresses the specified device as a Listener, and sends the PPC command followed by a PPE or PPD command.
Example
This example configures a device at PAD 2 to send DIO7 true if its IST bit = 1.
C int dev2;
dev2 = ibdev (0,2,0,13,1,0); ibppc (dev2, 0x6B);
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IBRD

Reads data from a device/interface board into a string.
Syntax
C ibrd (int boarddev, char buf[], unsigned long
Parameters
boarddev is an integer containing the board or device handle.
bytecount)
buf is the storage buffer for the data. Up to 4 gigabytes-1 (2
size may be limited by the language you are using. Check documentation for your language.
bytecount specifies the maximum number of bytes to read.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code of the first error detected, if an error occurred. An EADR
results if the specified GPIB Interface Board is an Active Controller but has not been addressed to listen. An
ibcnt, ibcntl will contain the number of bytes that were read. ibcnt is a 16-bit integer. ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of
ibcnt.
Usage Notes
A read will terminate when one of the following occurs:
The allocated buffer becomes full.
An error is detected.
The time limit is exceeded.
A terminator (or EOI) is detected.
EABO error results if a timeout occurs.
32
-1 bytes) can be stored. String
If
boarddev specifies a device, the specified device is addressed to talk and its associated
access board is addressed to listen.
If
boarddev specifies a GPIB Interface board, you must have already addressed a device as
a talker and the board as a listener. If the board is the Active Controller, it will unassert ATN in order to receive data. This routine leaves the board in that state.
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Example
Chapter 3 GPIB 488.1 Library Reference
This example reads 90 characters of data from a device at PAD 5.
C int dev5;
char rd [90]; dev5 = ibdev (0,5,0,13,1,0); ibrd (dev5, rd, 90);
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Chapter 3 GPIB 488.1 Library Reference

IBRDA

Reads data asynchronously from a device/interface board into a string.
Syntax
C ibrda (int boarddev, char buf[], unsigned long
Parameters
boarddev is an integer containing the device/board handle.
bytecount)
buf is the storage buffer for the data. Up to 4 gigabytes-1 (2
size may be limited by the language you are using. Check documentation for your language.
bytecount specifies the maximum number of bytes to read.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code of the first error detected, if an error occurred. An EADR
results if the specified GPIB board is an Active Controller but has not been addressed to listen. An
EABO error results if a timeout occurs.
ibcnt, ibcntl will contain the number of bytes that were read. ibcnt is a 16-bit integer. ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of
ibcnt.
Usage Notes
Asynchronous I/O is not explicitly supported and will be treated as synchronous.
Example
In this example, ibwrt sends the command "DUMP" to a device. The device responds by sending back a large block of data. and the program continues on into the WHILE loop. The WHILE loop calls
MASK set to 0 to update IBSTA. The WHILE loop checks IBSTA to see if ibrda has
completed, or if an error has occurred. The program may do anything else within the WHILE loop except make other GPIB I/O calls.
C char *readbuffer[5000];
32
-1 bytes) can be stored. String
ibrda begins a transfer of 5000 bytes in the background
ibwrt (device, "DUMP"); ibrda (device, readbuffer, 5000); while ( (ibsta & CMPL+ERR) == 0)
ibwait (device, 0)
ibwait with
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IBRDF

Reads data from the GPIB into a file.
Syntax
C ibrdf (int boarddev, char filename [])
Parameters
boarddev is an integer containing the board or device handle.
filename is the name of the file (up to 250 characters, including drive/path) in which the data
is to be stored. Be certain to specify a drive and path if necessary. This file is automatically opened as a binary file. It is created if it does not already exist.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. An EFSO error is generated if the file
can not be opened, created, found, written to, or closed.
ibcnt, ibcntl will contain the number of bytes that were read. ibcnt is a 16-bit integer. ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of
ibcnt.
Chapter 3 GPIB 488.1 Library Reference
Usage Notes
A read terminates when one of the following occurs:
The allocated buffer becomes full.
An error is detected.
The time limit is exceeded.
A terminator (or EOI) is detected.
A DCL or SDC command is received from the Active Controller.
If
boarddev specifies a device, the specified device is addressed to talk and its associated
access board is addressed to listen.
If
boarddev specifies a GPIB Interface board, you must have already addressed a device as
a talker and the board as a listener. If the board is the Active Controller, it unasserts ATN in order to receive data. This routine leaves the board in that state.
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Example
This program sends the command "DUMP" to a device. The device responds by sending data back.
ibrdf reads the incoming data and stores it in the file called gpib.dat on the C drive.
C ibwrt (boarddev, "DUMP");
ibrdf (boarddev, "c:gpib.dat");
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IBRPP

Initiates a parallel poll.
Syntax
C ibrpp (int boarddev, char *command)
Parameters
boarddev is an integer containing the device or board handle.
Returns
command will contain the response to the parallel poll.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
If this routine is called specifying a GPIB Interface Board, the board parallel polls all previously configured devices. If the routine is called specifying a device, the GPIB Interface board associated with the device conducts the parallel poll. Note that if the GPIB Interface Board to conduct the parallel poll is not the Controller-In-Charge, an ECIC error is generated.
Chapter 3 GPIB 488.1 Library Reference
Before executing a parallel poll, the with
ibppc to specify how they should respond to the poll.
ibppc function should configure the connected devices
Example
This program configures two devices for a parallel poll. It then conducts the poll. It is assumed that voltmeter and scope have already been set by opening the devices with an board has been set by opening the board with an
ibfind.
Both devices indicate that they want service by setting their first bit to 1. The first specifies that the first device ( goes high. The second line high when its first bit goes high. The
voltmeter) should drive the DIO1 line high when its first line
ibppc specifies that the second device (scope) should drive the DIO2
ibrpp conducts the poll and checks DIO1 and DIO2
to see if either device is requesting service.
C int voltmeter, scope, board, pollbyte;
ibppc (voltmeter, 0x68) ibppc (scope, 0x69) ibrpp (board, &pollbyte) if (pollbyte & 1)
printf "Volt meter is requesting service"
if (pollbyte & 2)
printf "Oscilloscope is requesting service"
GPIB-488 3-39 Programming Reference Manual
ibfind and
ibppc
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IBRSC

Request/Release System Control.
Syntax
C ibrsc (int board, int control)
Parameters
board is an integer containing the board handle.
control indicates whether the GPIB Interface Board is to become the system controller or
to relinquish system control capability. If the system controller on the GPIB. If
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. If no error occurs, iberr equals 1 if
the specified interface board was previously the system controller or 0 if it was not.
Usage Notes
There may only be one system controller in a GPIB system.
control is non-zero, the specified board becomes
control is 0, the board is not the system controller.
Example
This example makes GPIB board 1 the system controller.
C int gpib1;
gpib1 = ibfind ("gpib1"); ibrsc (gpib1, 3);
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IBRSP

Serial polls a device.
Syntax
C ibrsp (int device, char *serialpollbyte)
Parameters
device is an integer containing the device handle.
Returns
serialpollbyte will contain the serial poll response byte of the device. The serial poll
response byte is device-specific with the exception of bit 6. If bit 6 (hex 40) is set, then the device is requesting service. Consult the device's documentation for more information.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
If the automatic serial polling feature is enabled, the specified device may have been automatically polled previously. If it has been polled and a positive response was obtained, the RQS bit of status byte. If the RQS bit of device. This routine is used to serial poll one device, and obtain its status byte or to obtain a previously stored status byte. If bit 6 (the hex 40 bit) of the response is set, the device is requesting service.
Chapter 3 GPIB 488.1 Library Reference
ibsta is set on that device. In this case ibrsp returns the previously acquired
ibsta is not set during an automatic poll, it serial polls the
When a serial poll occurs, the following sequence of events happens. The board sends an UNL (unlisten) command. It then addresses itself as a listener and sends a SPE (Serial Poll Enable) Byte. It then addresses a device as a talker. The board then reads the serial poll response byte from the device. The board then sends a serial poll disable (SPD) and untalks and unlistens all devices.
Example
Returns the serial response byte (into serialpollbyte) of a device at PAD 1.
C int dev1;
char serialpollbyte; dev1 = ibdev (0,1,0,13,1,0); ibrsp (dev1, &serialpollbyte);
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IBRSV

Changes the serial poll response byte.
Syntax
C ibrsv (int board, int statusbyte)
Parameters
board is an integer containing the board handle.
statusbyte represents the serial poll response byte of the GPIB Interface Board. The serial
poll response byte is system-specific, with the exception of bit 6 (hex 40). If bit 6 (hex 40) is set, then the SRQ line is asserted to indicate to the Controller-In-Charge that the board is requesting service.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. If no error occurs, iberr will contain
the previous value of
statusbyte.
Usage Notes
This routine is used when the specified GPIB Interface Board is not the Controller-In-Charge. It can be used to request service (set bit 6 of the serial response byte) from the Controller-In-Charge or to change the value of GPIB Interface Board's serial poll response byte.
Example
This example sets the GPIB Interface Board 1 serial poll status byte to 41 hex (assert SRQ) which indicates that the board requires service.
C int gpib1;
gpib1 = ibfind ("gpib1"); ibrsv (gpib1, 0x41);
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IBSAD

Assigns/unassigns a secondary address to a board or device.
Syntax
C ibsad (int boarddev, int address)
Parameters
boarddev is an integer containing device or board handle.
address represents the secondary address. If address = 0 or address = 7F hex, secondary
addressing is disabled. If secondary address is temporarily assigned to the board/device. The new secondary address is used until it is either redefined by calling calling
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurs. Contains the previously assigned
secondary address if no error occurs.
Chapter 3 GPIB 488.1 Library Reference
address is a legal secondary address (60 to 7E hex), the new
ibsad again, the device/board is re-initialized by
ibfind or ibonl, or the program is restarted.
Usage Notes
See also ibpad.
Example
This example assigns the secondary address 7 (MSA7, hex 67) to a device at PAD 5.
C int dev5;
dev5 = ibdev (0,5,0,13,1,0); ibsad (dev5, 0x67);
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IBSIC

Asserts IFC (Interface Clear) signal. This re-initializes the GPIB system.
Syntax
C ibsic (int board)
Parameters
board is an integer containing the board handle.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. The ESAC error is generated if the
specified GPIB Interface Board is not the system controller.
Usage Notes
This routine can only be used if the specified GPIB board is the system controller. When the routine is executed, the GPIB interface board asserts the least 100 µsec. This action results in the system controller regaining control of the GPIB (for example, becoming the Controller-In-Charge). When functions of the bus devices are reset.
IFC (Interface Clear) signal for at
IFC line is asserted, all GPIB interface
Example
This example resets the GPIB bus associated with the specified GPIB Interface Board and makes that board Controller-In-Charge.
C int gpib1;
gpib1 = ibfind("GPIB1"); ibsic (gpib1);
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IBSRE

Asserts/Unasserts the REN (Remote Enable) line.
Syntax
C ibsre (int board, int ren)
Parameters
board is an integer containing the board handle.
ren specifies whether the REN line is to be asserted or unasserted. If ren is zero, the REN line
is unasserted. Otherwise, the
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. The ESAC error is generated if the
specified GPIB interface board is not the system controller. Contains the previous if no error occurs.
Usage Notes
This routine can only be used if the specified GPIB interface board is the system controller.
Chapter 3 GPIB 488.1 Library Reference
REN line is asserted.
REN state
Even though the
REN line is asserted, the device(s) is not put into remote state until is
addressed to listen by the Active Controller. When the REN line is unasserted, all devices return to local control.
Example
This example puts the device at MLA 12 (2C hex, ASCII ,) and associated with GPIB Interface Board 1 in remote mode.
C int gpib1:
gpib1 = ibfind ("GPIB1"); ibsre (gpib1, 2); /* Use any non-zero
value */
ibcmd (gpib1,",", 1);
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IBSTOP

Terminate an asynchronous operation.
Syntax
C ibstop (int boarddev)
Parameters
boarddev is an integer containing the device or board handle.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA. If an operation
is terminated, the
iberr will contain an error code, if an error occurred. If an operation is terminated, an EABO
error is returned.
Usage Notes
If a device is specified, all unfinished asynchronous operations (read, write, or command) associated with that device is stopped. If a GPIB Interface Board is specified, all unfinished asynchronous operations associated with that board is stopped. Once the operation(s) have been terminated, the application is resynchronized with the driver.
ERR bit is set.
Example
This example starts a background write command and then immediately stops it.
C int dev;
dev = ibdev (0,2,0,13,1,0); ibwrta(dev, "datafile"); ibstop (dev);
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IBTMO

Changes timeout value.
Syntax
C int ibtmo (int boarddev, int timeout)
Parameters
boarddev is an integer containing the board or device handle.
timeout specifies the timeout. The timeout value determines how long I/O routines wait for
a response from a device. When the timeout period expires during an I/O operation, the I/O function returns an
Chapter 3 GPIB 488.1 Library Reference
EABO error. Valid timeout codes are shown in Table 3-6.

Table 3-6. Timeout Codes

Minimum
Code Val ue
TNONE 0 Disabled T100ms 9 100 msec
T10us 1 10 msec T300ms 10 300 msec
T30us 2 30 msec T1s 11 1 sec
T100us 3 100 msec T3s 12 3 sec
T300us 4 300 msec T10s 13 10 sec
T1ms 5 1 msec T30s 14 30 sec
T3ms 6 3msec T100s 15 100 sec
T10ms 7 10msec T300s 16 300 sec
T30ms 8 30 msec T1000s 17 1000 sec
timeout
Code Va lu e
Minimum
timeout
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. Contains the previous timeout code if
no error occurs.
Usage Notes
This routine is used to temporarily change the default timeout value assigned to the device/GPIB Interface board.
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The new timeout is used until it is redefined (by calling ibtmo again) the device/board is re-initialized (by calling
Example
This example changes the timeout (to 30 sec) for all calls specifying the "plotter" device at PAD 3 .
C int plotter;
ibfind or ibonl); or the system is restarted.
plotter = ibdev (0,3,0,13,1,0); ibtmo(plotter, T30us);
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IBTRG

Triggers the specified device.
Syntax
C ibtrg (int device)
Parameters
device is an integer containing device handle.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the GPIB Interface Board associated with the device is addressed to talk and all devices are unlistened. The specified device is then addressed to listen and a GET (Group Execute Trigger) command is sent.
Example
This example triggers the specified device.
C int plotter;
Chapter 3 GPIB 488.1 Library Reference
plotter = ibdev (0,6,0,13,1,0); ibtrg (plotter);
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IBWAIT

Forces application program to wait for a specified event(s) to occur.
Syntax
C ibwait (int boarddev, int mask)
Parameters
boarddev is an integer containing the board or device handle.
mask specifies the events that ibwait will wait for. Each bit in mask represents a different
event. These bits are the same as the bits in
Bit 15 14 13 12 11 10 9 8
Event ERR TIMO END SRQI RQS CMPL
Bit 7 6 5 4 3 2 1 0
ibsta positions.
Event LOK REM CIC AT N TAC S LACS DTAS DCAS
For more information regarding
ibsta, see Appendix B, IBSTA.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
Because the mnemonic for each bit of ibsta is defined as a constant within the header file, you can elect to use the mnemonic rather than the hex value. If if the event does not occur within the timeout period of the device.
If a GPIB interface board is specified, the
RQS bit is not applicable.
TIMO is set, ibwait returns
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Example
Chapter 3 GPIB 488.1 Library Reference
This example forces your program to wait indefinitely for the specified device to request service.
C int plotter;
plotter = ibdev (0,1,0,13,1,0); ibwait (plotter, RQS);
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IBWRT

Writes data from a string to the specified device or GPIB Interface Board.
Syntax
C ibwrt (int boarddev, char buf[], unsigned long
Parameters
boarddev is an integer containing the board or device handle.
bytecount)
buf is the string containing the data to be written. buf can contain up to 4 gigabytes-1 (2
bytes). String size may be limited by the language you are using. Check documentation for your language.
bytecount specifies the number of bytes to be written from the string.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code of the first error detected, if an error occurred. An EADR
results if
ibcnt, ibcntl will contain the number of bytes that were written. ibcnt is a 16-bit integer. ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of
ibcnt.
Usage Notes
This routine is used to send device-specific commands. A write terminates when one of the following occurs:
All bytes are transferred.
An error is detected.
The time limit is exceeded.
A DCL (Device Clear) or SDC (Selected DC) is received from the CIC.
All data is sent.
32
boarddev specifies a board and the board has not already been addressed to talk.
-1
If
boarddev specifies a device, the specified device is addressed to listen and its associated
access board is addressed to talk. If
boarddev specifies a GPIB Interface Board, the
Controller-In-Charge must have already addressed a device as a listener and the board as a talker. If the board is the Active Controller, it unasserts ATN in order to send data. This routine leaves the board in that state.
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Example
Chapter 3 GPIB 488.1 Library Reference
If you want to send an EOS character at the end of the data string, you must include it in the string.
This example sends five bytes terminated by a carriage return and line feed to the specified device.
C int ptr;
ptr = ibdev (0,7,0,13,1,0); ibwrt (ptr,"IP2X5\r\n", 7);
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IBWRTA

Writes data asynchronously from a string to the specified device or GPIB interface board.
Syntax
C ibwrta (int boarddev, char buf[], unsigned long
Parameters
boarddev is an integer containing the board or device handle.
bytecount)
buf is the storage buffer for the data. Up to 4 gigabytes-1 (2
size may be limited by the language you are using. Check documentation for your language.
bytecount specifies the number of bytes to be written.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code of the first error detected, if an error occurred. An EADR
results if
ibcnt, ibcntl will contain the number of bytes that were written. ibcnt is a 16-bit integer. ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of
ibcnt.
Usage Notes
Asynchronous I/O is not explicitly supported and will be treated as synchronous.
Example
In this example, ibwrt sends a command ("UPLOAD") to a device. The device expects a block of data to be sent immediately. program continues on into the WHILE loop. The WHILE loop calls to 0 to update error have occurred. The program may do anything else within the WHILE loop except make other GPIB I/O calls.
C char writebuffer[5000];
32
-1 bytes) can be stored. String
boarddev specifies a board and the board has not already been addressed to talk.
ibwrta begins a transfer of 5000 bytes in the background and
ibwait with MASK set
ibsta. The WHILE loop checks ibsta to see if ibwrta has completed or any
ibwrt (device, "UPLOAD") ibwrta (device, writebuffer, 5000); while ( (ibsta & CMPL+ERR) == 0)
ibwait (device, 0)
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IBWRTF

Writes data from a file to the specified device or GPIB Interface Board.
Syntax
C ibwrtf (int boarddev, char filename [])
Parameters
boarddev is an integer containing the board or device handle.
filename is the name of the file (up to 50 characters, including drive/path) to store the data.
Specify a drive and path if necessary. This file is automatically opened as a binary file.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred. An EFSO error is generated if the file
can not be found.
ibcnt, ibcntl will contain the number of bytes that were written. ibcnt is a 16-bit integer. ibcntl is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead
of
ibcnt.
Chapter 3 GPIB 488.1 Library Reference
Usage Notes
A write terminates when one of the following occurs:
An error is detected.
The time limit is exceeded.
A DCL or SDC is received from the Active Controller.
All data has been sent.
If
boarddev specifies a device, the specified device is addressed to talk and its associated
access board is addressed to listen. If
boarddev specifies a GPIB interface board, you must
have already addressed a device as a listener and the board as a talker. If the board is the CIC, it unasserts ATN in order to receive data. This routine leaves the board in that state.
Example
This program sends the command "UPLOAD" to a device and prepares the device to receive a large amount of data. The program then sends the data from a file to the device.
C int device;
ibwrt (device, "UPLOAD"); ibwrtf (device, "c:gpib.dat");
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GPIB 488.2 Library Reference
This chapter describes each of the 488.2 GPIB library routines. A short description of the routine, its syntax, parameters, any values that are returned, any special usage notes, and an example are included for each routine. The routines are listed in alphabetical order. The following table lists all of the 488.2 GPIB library routines. A full description of each routine follows the table.
Note 488.2 addresses contain two bytes packed into a word – the low byte is the primary
address and the high byte is the secondary address. If secondary addressing is not used, the high byte should be zero.

Table 4-1. 488.2 Address word

HIGH BYTE LOW BYTE
Secondary Address (0 or 96-126) Primary Address (0-30)
488.2 routines use a board index as the first argument (typically zero) – not a handle.
4
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AllSpoll

Performs a serial poll on specified devices.
Syntax
C AllSpoll (int board, short addresslist[],
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to be serial polled.
Returns
resultlist is an array which contains the results of the serial poll. Once a device has been
serial polled, the results of the serial poll are stored in the corresponding element of
resultlist.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
short resultlist[])
iberr will contain an error code, if an error occurred. If a device times out, iberr contains
Error 6 –
EABO (see Appendix C, IBERR), and ibcnt contains the index of the timed-out
device.
Usage Notes
To poll only one GPIB device, use ReadStatusByte.
Example
This example serial polls two devices (GPIB address 6 and 7) connected to GPIB board 0.
C short addresslist[3] = {6,7,NOADDR};
short resultlist[2]; AllSpoll (0, addresslist, resultlist);
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DevClear

Clears one device.
Syntax
C DevClear(int board, short address)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is the GPIB address of the device to clear.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine sends the GPIB Selected Device Clear (SDC) message to the specified device.
Chapter 4 GPIB 488.2 Library Reference
To clear multiple devices, use the
If
address is set to NOADDR, then all connected devices on the GPIB is cleared through the
Universal
Device Clear (UDC) message.
DevClearList routine.
Example
This example clears the device at GPIB primary address 4, secondary address 30 connected to GPIB board 0.
C DevClear(0, MakeAddr (4,30));
/* Use MakeAddr macro (in GPIB.H) to pack
primary and secondary address */
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DevClearList

Clears specified devices.
Syntax
C DevClearList(int board, short addresslist[])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to be cleared.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine sends the GPIB Selected Device Clear (SDC) to the devices specified by
addresslist.
To clear only one device, use
DevClear.
Example
This clears the devices at GPIB addresses 6 and 7, connected to GPIB board 0.
C short addresslist[3] = {6,7,NOADDR};
DevClearList(0, addresslist);
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EnableLocal

Places specified devices in local mode (Can be "programmed" from front panel controls.).
Syntax
C EnableLocal(int board, short addresslist[])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to enable locally.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the Controller addresses the specified GPIB devices as listeners and then sends the GPIB
Chapter 4 GPIB 488.2 Library Reference
Go To Local (GTL) command.
To put all devices in local mode, use an array containing only the unasserts the GPIB mode.
Remote Enable (REN) line, thereby placing all GPIB devices in local
NOADDR value. This
Example
Put the GPIB devices at addresses 6 and 7 (connected to board 0) in local mode.
C short addresslist[3] = {6,7,NOADDR};
EnableLocal(0, addresslist);
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EnableRemote

Allow remote programming (by sending messages over the GPIB line) of a device.
Syntax
C EnableRemote(int board, short addresslist[])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to be put in remote programming mode.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the system controller asserts the Remote Enable (REN) line and the Controller addresses the specified devices as listeners.
Example
Places devices at GPIB addresses 6 and 7 (connected to GPIB board) in remote mode.
C short addresslist[3] = {6,7,NOADDR};
EnableRemote(0, addresslist);
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FindLstn

Finds all listeners on the GPIB.
Syntax
C FindLstn(int board, short addresslist[], short
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR.
limit is an integer which specifies how many address entries can be placed into the resultlist array. Set to the size of the resultlist array.
Returns
resultlist will contain the addresses of all detected listeners. This array must be large
enough to hold all possible addresses.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
Chapter 4 GPIB 488.2 Library Reference
resultlist[], int limit)
iberr will contain an error code, if an error occurred. An ETAB (20) error indicates that more
listeners are present on the GPIB bus than limit will allow to be placed in this case,
ibcnt contains the number of addresses actually placed in resultlist.
resultlist. In
Usage Notes
The addresses specified by addresslist are tested to see if a listening device is present. If a listener is found at a primary address, its address is placed in
resultlist. If no listeners
are detected at a primary address, then all secondary addresses associated with that primary address are tested. If any listeners are detected, their addresses are placed in
resultlist.
You can use this routine to determine how many devices on the network are capable of listening. Once these devices are detected, they can be identified by their response to identification request messages.
Example
This example verifies if listening devices are present at GPIB primary addresses 6 and 7 on Board 0.
C short addresslist[3] = {6,7,NOADDR};
short resultlist[4]; FindLstn(0, addresslist, resultlist, 4);
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FindRQS

Identify the device requesting service.
Syntax
C FindRQS(int board, short addresslist[], short
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. The devices
located at these addresses are serial polled until the one asserting SRQ is located.
Returns
result will contain the returned status byte of the device asserting SRQ.
ibcnt will contain the index (in addresslist) identifying the device's address.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
*result)
iberr will contain an error code, if an error occurred. iberr contains the error code ETAB,
if no device is requesting service. In this case,
iberr will contain the error code EABO if a device times out while responding to its serial
poll. In this case,
ibcnt contains the index of the timed-out device.
ibcnt contains NOADDR's index.
Usage Notes
None.
Example
Identifies which of the devices at GPIB addresses 6 and 7 (connected to board 0) is requesting service.
C
short addresslist[3] = {6,7,NOADDR}; short result; FindRQS (0, addresslist, &result);
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PassControl

Makes another device the Active Controller.
Syntax
C PassControl(int board, short address)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is an integer representing the GPIB address of the device that is to become the
controller. The low byte of the integer contains the device's primary GPIB address. The high byte of the address contains the device's secondary GPIB address. If the device has no secondary address, the high byte of
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Chapter 4 GPIB 488.2 Library Reference
address is 0.
Usage Notes
When this routine is executed, the GPIB Take Control (TCT) command is issued. This forces the Active Controller to pass control to the device at the specified address. This device must have Controller capability.
Example
This example would make the device connected to Board 0 and whose GPIB address is 6 the Active Controller.
C PassControl(0, 6);
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Chapter 4 GPIB 488.2 Library Reference

Ppoll

Performs a parallel poll.
Syntax
C PPoll(int board, short *result)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
Returns
result will contain the eight-bit result of the parallel poll. Each bit of the poll result contains
one bit of status information from each device which has been configured for parallel polls. The value of each bit is dependent on the latest parallel poll configuration sent to the devices through
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
PPollConfig and the individual status of the devices.
Usage notes
None.
Example
Parallel polls devices connected to board 0.
C short result;
PPoll(0, &result);
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PPollConfig

Configures a device for parallel polls.
Syntax
C PPollConfig(int board, short address, int
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is the address of the GPIB device to be configured for a parallel poll.
dataline specifies which data line (1-8) the device uses to respond to a parallel poll.
sense can be 1 or 0, specifying the condition under which the data line is to be
asserted/unasserted. The device compares this value to its Individual Status Bit (IST) and then responds accordingly. For example, if if its IST bit = 0 and unassert the data line if its IST bit = 1.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
Chapter 4 GPIB 488.2 Library Reference
dataline, int sense)
sense = 0 and the device asserts the specified data line
iberr will contain an error code, if an error occurred.
Usage notes
Remember that if a device is locally configured for a parallel poll, the Controller's parallel poll configuration instruction is ignored.
Example
Configures the device connected to board 0 at address 6 to respond to parallel polls on line 7 with sense 1. The device asserts line 7 if its IST bit = 1, and unasserts line 7 if IST = 0.
C PPollConfig(0, 6, 7, 1)
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Chapter 4 GPIB 488.2 Library Reference

PPollUnconfig

Unconfigures devices for parallel polls.
Syntax
C PPollUnconfig(int board, short addresslist[])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices that do not respond to a parallel poll.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Example
Unconfigure the devices connected to board 0 and located at GPIB addresses 6 and 7.
C short addresslist[3] = {6, 7, NOADDR};
PPollUnconfig(0, addresslist);
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RcvRespMsg

Reads data from a previously addressed device.
Syntax
C RcvRespMsg(int board, char data[], long count,
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
count specifies the maximum number of data bytes which are to be read.
termination is the flag used to signal the end of data. If termination equals a value
between 0 and 00FF hex, the corresponding ASCII character is the termination character. The read is stopped when this character is detected. If defined in the header file), then the read is stopped when EOI is detected.
Returns
data is the string that receives the data.
Chapter 4 GPIB 488.2 Library Reference
int termination)
termination = STOPend (A constant
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
You must address the appropriate devices as Listeners/Talkers prior to calling this routine. The input data string is not terminated with a zero byte.
Example
A previously addressed Listener receives 50 bytes of data from a previously addressed Talker. The transmission is terminated when EOI is detected.
C char data[50];
RcvRespMsg(0, data, 50, STOPend)
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Chapter 4 GPIB 488.2 Library Reference

ReadStatusByte

Serial poll a single device and read its status byte.
Syntax
C ReadStatusByte(int board, int address, short
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is an integer representing the GPIB address of the device that is to be serial polled.
Returns
result will contain the status byte. The high byte of result is always 0.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
None.
*result)
Example
This example serial polls the device at address 2 and retrieves its status byte.
C short result;
ReadStatusByte (0, 2, &result);
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Receive

Reads data from a GPIB device.
Syntax
C Receive(int board, int address,char data[],
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is an integer representing the GPIB address of the device that is to be read from.
count specifies the maximum number of data bytes which are to be read.
termination is the flag used to signal the end of data. If termination equals a value
between 0 and 00FF hex, the corresponding ASCII character is the termination character. The read is stopped when this character is detected. If defined in the header file), then the read is stopped when EOI is detected.
Returns
data is the string that receives the data.
Chapter 4 GPIB 488.2 Library Reference
unsigned long count, int termination)
termination = STOPend (constant
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
The input data string is not terminated with a zero byte.
Example
Receive 50 bytes of data from the specified talker (device at address 2, connected to board). EOI signals the end of the message.
C char data[50];
Receive (0, 2, data, 50, STOPend);
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Chapter 4 GPIB 488.2 Library Reference

ReceiveSetup

Address a GPIB Interface Board as a Listener and a GPIB device as a Talker, in preparation for data transmission.
Syntax
C ReceiveSetup(int board, short address)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is an integer representing the GPIB address of the device to send the data.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
In order to actually transfer any data, you must call a routine such as RcvRespMsg following this routine.
This routine is useful in instances where you need to transfer multiple blocks of data between devices. For example, you could initially address the devices using make multiple calls of
For typical cases,
RcvRespMsg to transfer the data.
Receive is simpler to use, since it takes care of both the setup and the data
ReceiveSetup, then
transfer.
Example
This example instructs a GPIB device at address 5 to send data to GPIB Board 0. Up to 50 bytes of data is received and then stored in a string. The message is terminated with an EOI.
C char message[100];
ReceiveSetup(0, 5); RcvRespMsg (0, message, 50, STOPend);
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ResetSys

Initializes GPIB System.
Syntax
C ResetSys(int board, short addresslist[])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices on the system to be reset.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine initializes the GPIB bus and all specified devices. First, the system controller asserts the REN (Remote Enable) line and then the IFC (Interface Clear) line. This action unlistens and untalks all of the attached GPIB devices and causes the system controller to become the Controller-In-Charge (CIC).
Chapter 4 GPIB 488.2 Library Reference
The Device Clear (DCL) message is then sent to all of the connected devices. This forces the devices to return to their default states and ensures that they can receive the Reset (RST) message. A reset message (RST) is then sent to all of the devices specified by This resets the devices to specific parameters.
addresslist.
Example
This example resets the GPIB devices connected to GPIB board 0 and assigned GPIB bus addresses of 6 and 7.
C short addresslist[3] = {6, 7, NOADDR};
ResetSys(0, addresslist);
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Chapter 4 GPIB 488.2 Library Reference

Send

Sends data to one GPIB device.
Syntax
C Send (int board, short address,char data[],
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
address is an integer representing the GPIB address of the device to receive the data.
data is the string of data which is sent to the device.
count specifies the maximum number of data bytes which are to be sent to the device.
eotmode is the flag used to signal the end of data.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
long count, int eotmode)
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the specified GPIB board is addressed as a Talker, the designated GPIB device is addressed as a Listener and the number of bytes (specified by
count) in data is sent. Values for eotmode are:
NLend—Send NL (Line Feed) with EOI after last data byte.
DABend—Send EOI with the last data byte in the string.
NULLend—Do not mark the end of the transfer.
These constants are defined in the header file.
Example
In this example, GPIB board 0 sends an identification query to the GPIB device at address 3. End of data is signalled by an EOI.
C Send (0, 3, "*IDN?", DABend)
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SendCmds

Send GPIB commands.
Syntax
C SendCmds (int board, char commands[],
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
commands is a string containing the GPIB command bytes to be sent.
count specifies the maximum number of command bytes which are to be sent.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine is useful in situations where specialized GPIB command sequences are called for.
Chapter 4 GPIB 488.2 Library Reference
unsigned long count)
Example
The GPIB board (at 0) simultaneously triggers the GPIB devices at addresses 8 and 9 and quickly puts them in local mode.
C SendCmds0, "\x3F\x40\x28\x29\x04\x01",6);
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Chapter 4 GPIB 488.2 Library Reference

SendDataBytes

Sends data to previously addressed devices.
Syntax
C SendDataBytes(int board, char data[], long count,
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
data is the string that contains the data which is sent to the device.
count specifies the maximum number of data bytes which are to be sent to the device.
eotmode is the flag used to signal the end of data.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
int eotmode)
Usage Notes
This routine assumes that the desired GPIB listeners have already been addressed (by using
SendSetup, for example).
Val u es f o r
eotmode are as follows:
NLend—Send NL (Line Feed) with EOI after last data byte.
DABend—Send EOI with the last data byte in the string.
NULLend—Do not mark the end of the transfer.
These constants are defined in the header files.
Example
In this example, GPIB board 0 sends an identification query to all previously addressed listeners. End of data is signaled by an EOI.
C SendDataBytes (0, "*IDN?", 5, DABend)
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SendIFC

Clears the GPIB bus by asserting the IFC (Interface Clear) line.
Syntax
C SendIFC(int board)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine is used as part of the GPIB initialization procedure. When the system controller asserts the IFC line, it unlistens and untalks all GPIB devices, forcing them to an idle state. The system controller also becomes the Controller-In-Charge (CIC).
Chapter 4 GPIB 488.2 Library Reference
Example
Clears the GPIB bus from Board 0.
C SendIFC(0);
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SendList

Sends data to multiple GPIB devices.
Syntax
C SendList(int board, short addresslist[],
Parameters
board is an integer which identifies the GPIB board to use for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices on the system to reset.
data is the string containing the data to send.
count specifies the maximum number of data bytes to send to the device.
eotmode is the flag used to signal the end of data.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
char data[], long count, int eotmode)
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the specified GPIB board is addressed as a Talker and the designated GPIB devices as Listeners. The board then sends the given number of bytes of data from the data string to the listening GPIB devices.
NLend—Send NL (Line Feed) with EOI after last data byte.
DABend—Send EOI with the last data byte in the string.
NULLend—Do not mark the end of the transfer.
These constants are defined in the header files.
Example
In this example, GPIB board 0 sends an identification query to the GPIB devices at addresses 6 and 7. End of data is signalled by an EOI.
C short addresslist[3] = {6, 7, NOADDR};
SendList (0, addresslist, "*IDN?", 5, DABend)
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SendLLO

Sends Local Lockout (LLO) message to all GPIB devices.
Syntax
C SendLLO(int board)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, the specified GPIB board sends the GPIB Local Lockout (LLO) message to all devices. This means that once they have been addressed as listeners, the devices respond only to messages sent over the GPIB by the Controller. (In other words, they can not be locally programmed from front panel controls.) Only the Controller can return them to a local programming state.
Chapter 4 GPIB 488.2 Library Reference
Example
In this example, GPIB board 0 sends a Local Lockout to its connected GPIB devices.
C SendLLO (0);
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Chapter 4 GPIB 488.2 Library Reference

SendSetup

Addresses a GPIB board as a Talker and the specified GPIB devices as Listeners.
Syntax
C SendSetup(int board, short addresslist [])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to address as Listeners.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
Following this routine, you should call a routine such as SendDataBytes to actually transfer the data.
Example
This example prepares GPIB board 0 to send data to GPIB devices 6 and 7.
C short addresslist[3] = {6, 7, NOADDR};
SendSetup(0, addresslist);
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SetRWLS

Puts all devices in Remote state with Local Lockout and addresses specified devices as Listeners.
Syntax
C SetRWLS(int board, short addresslist [])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to be put in remote mode.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This routine puts the specified devices in remote mode with local lockout. The system controller asserts the REN (Remote Enable) line and addresses the specified devices as listeners. These devices can then be programmed by messages sent over the GPIB bus. (In other words, they can not be locally programmed from front panel controls.)
Chapter 4 GPIB 488.2 Library Reference
Example
This example puts all devices controlled by GPIB board 0 into Remote mode. Devices 6 and 7 are then addressed as Listeners by the Controller.
C short addresslist[3] = {6, 7, NOADDR};
SetRWLS(0, addresslist);
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Chapter 4 GPIB 488.2 Library Reference

TestS RQ

Evaluate state of SRQ line.
Syntax
C TestSRQ(int board, short *result)
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
Returns
result is equal to 1 if the GPIB SRQ line is asserted. result = 0 if the GPIB SRQ line is
unasserted.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
TestSRQ will not alter the state of the SRQ line.
Example
This example tests to see if SRQ is asserted.
C Short result;
TestSRQ (0, &result); if (result == 1)
{ /* SRQ is asserted */} else
{ /* No SRQ at this time */}
Programming Reference Manual 4-26 GPIB-488
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TestS ys

Activate self-test procedures of specified devices.
Syntax
C SendSetup(int board, short addresslist [],
Parameters
board is an integer which identifies the GPIB board to use for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to perform self-tests.
Returns
resultlist is an array which contains the results of each device's self-test procedure.
According to the IEEE-488.2 standard, a result code of 0 indicates the device passed its test. Any other value indicates an error.
ibcnt will contain the number of devices which failed their tests.
Chapter 4 GPIB 488.2 Library Reference
short resultlist[])
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this routine is executed, all of the devices identified within the addresslist array are concurrently sent a message which directs them to perform their self-test procedures. Each device returns an integer code indicating the results of its tests. This code is placed into the corresponding element of the
resultlist array.
Example
This example tells the devices at addresses 6 and 7 (from Board 0) to perform thier self-test procedures.
C short addresslist[3] = {6, 7, NOADDR};
short resultlist[2]; TestSys(0, addresslist, resultlist);
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Chapter 4 GPIB 488.2 Library Reference

Trigg er

Triggers one device.
Syntax
C Trigger(int board, short address)
Parameters
board is an integer which identifies the GPIB board to used for this operation. In most
applications, this value is 0.
address is an integer representing the GPIB address of the device to trigger. If address = NOADDR then all Listeners already addressed are triggered.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
When this call is executed, the GPIB GET (Group Execute Trigger) message is sent to the specified device.
To trigger several GPIB devices, use
TriggerList.
Example
This example triggers a device connected to board 0 whose primary GPIB address is 6 and secondary address is 12.
C Trigger (0, MakeAddr (6, 12));
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TriggerList

Triggers multiple GPIB devices
Syntax
C void TriggerList(int board, int addresslist[])
Parameters
board is an integer which identifies the GPIB board to be used for this operation. In most
applications, this value is 0.
addresslist is an array of GPIB addresses, terminated by the value NOADDR. These
addresses identify the devices to be triggered. If this array contains only previously addressed listeners are triggered.
Returns
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
Use Trigger to trigger only one device.
Chapter 4 GPIB 488.2 Library Reference
NOADDR, all
Example
This example triggers two devices simultanously. The devices are connected to board 0 and are at GPIB addresses 6 and 7.
C short addresslist[3] = {6, 7, NOADDR};
TriggerList(0, addresslist);
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Chapter 4 GPIB 488.2 Library Reference

WaitSRQ

Wait until a device asserts SRQ.
Syntax
C WaitSRQ(int board, short *result)
Parameters
board is an integer which identifies the GPIB board to use for this operation. In most
applications, this value is 0.
Returns
result indicates whether or not an SRQ occurred. If an SRQ occurs before the timeout
expires,
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA.
iberr will contain an error code, if an error occurred.
Usage Notes
This call suspends operation until a device requests service or a timeout occurs. Follow this call with a
result = 1. Otherwise, result = 0.
FindRQS call to determine which device needs service.
Example
Wait for a GPIB device to request service and then ascertain if device 6 or 7 requires service.
C short addresslist[3] = {6,7,NOADDR};
short resultlist[3]; short result; WaitSRQ (0,&result); if (result == 1)
{FindSRQ (0, addresslist, resultlist)}
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A
Multiline Interface Messages

Table A-1. Multiline Interface Messages (Hex 00-3F)

HEX DEC ASCII MSG HEX DEC ASCII MSG
00 0 NUL 20 32 SP MLA0
01 1 SOH GTL 21 33 ! MLA1
02 2 STX 22 34 MLA2
03 3 ETX 23 35 # MLA3
04 4 EOT SDC 24 36 $ MLA4
05 5 ENQ PPC 25 37 % MLA5
06 6 ACK 26 38 & MLA6
07 7 BEL 27 39 MLA7
08 8 BS GET 28 40 ( MLA8
09 9 HT TCT 29 41 ) MLA9
0A 10 LF 2A 42 * MLA10
0B 11 VT 2B 43 + MLA11
0C 12 FF 2C 44 MLA12
0D 13 CR 2D 45 - MLA13
0E 14 SO 2E 46 > MLA14
0F 15 SI 2F 47 / MLA15
10 16 DLE 30 48 0 MLA16
11 17 DC1 LLO 31 49 1 MLA17
12 18 DC2 32 50 2 MLA18
13 19 DC3 33 51 3 MLA19
14 20 DC4 DCL 34 52 4 MLA20
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Appendix A Multiline Interface Messages
Table A-1. Multiline Interface Messages (Hex 00-3F) (Continued)
HEX DEC ASCII MSG HEX DEC ASCII MSG
15 21 NAK PPU 35 53 5 MLA21
16 22 SYN 36 54 6 MLA22
17 23 ETB 37 55 7 MLA23
18 24 CAN SPE 38 56 8 MLA24
19 25 EM SPD39 39 57 9 MLA25
1A 26 SUB 3A 58 : MLA26
1B 27 ESC 3B 59 ; MLA27
1C 28 FS 3C 60 < MLA28
1D 29 GS 3D 61 = MLA29
1E 30 RS 3E 62 > MLA30
1F 31 US 3F 63 ? UNL

Table A-2. Multiline Interface Messages (Hex 40-7F)

HEX DEC ASCII MSG HEX DEC ASCII MSG
40 64 @ MTA0 60 96 MSA0,P
PE
41 65 A MTA1 61 97 a MSA1,P
PE
42 66 B MTA2 62 98 b MSA2,P
PE
43 67 C MTA3 63 99 c MSA3,P
PE
44 68 D MTA4 64 100 d MSA4,P
PE
45 69 E MTA5 65 101 e MSA5,P
PE
46 70 F MTA6 66 102 f MSA6,P
PE
Programming Reference Manual A-2 GPIB-488
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