Measurement Computing Corporation 488 GPIB Interface Programming Reference Manual
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GPIB-488
GPIB-488 Programming Reference Manual
Programming Reference Manual
July 2006
371930C-01
© Copyright 1996-2006 by Measurement Computing Corporation’s licensor(s). All rights reserved.
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bold
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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 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
GPIB terms used within this manual are:
GPIB General Purpose Interface Bus
System controller
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.
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
Active controller
Device
Listener
Talker 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.
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.
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.
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.
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.
Contents
Chapter 1
GPIB Software Overview
Chapter 2
Programming with the GPIB Library
Chapter 3
GPIB 488.1 Library Reference
IBEOS ............................................................................................................................3-18
GPIB-488 v
Contents
IBPAD ........................................................................................................................... 3-30
Chapter 4
GPIB 488.2 Library Reference
vi GPIB-488
Contents
Appendix A
Multiline Interface Messages
Appendix B
IBSTA
Appendix C
IBERR
GPIB-488 vii
1
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 " ib
". The 488.1 library routines refer 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 " ib
". The 488.2 library routines refer to devices on the GPIB 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.
Table 1-1. Programming Languages
Programming Languages
Delphi
C
VB
GPIB-488 1-1
Chapter 1 GPIB Software Overview
GPIB Library Utility Programs
The following utility programs are installed with the GPIB library software.
Utility program
GPIBDIAGNOSTIC.EXE
GPIBINTERACTIVECONTROL.EXE
GPIBCONFIGURATION.EXE
Description
Hardware test program (Win32)
Interactive control program (Win32)
Configuration utility program (Win 32)
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 gpib-32.DLL
.
ibnotify
The GPIB library does not support ibnotify
. Applications that utilize the ibnotify
function will not run properly.
1-2 GPIB-488
2
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 " ib
". This library uses a concept of device names and handles rather 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 same program can run on different buses where the addresses of each device are different.
• The program can refer to each device with an intelligible name rather than a number (the GPIB address).
488.2 library—This library consists of all the routines that do not begin with the letters " ib
". These routines refer to all devices on the bus by their
GPIB addresses rather than by names. The
section does not apply to the 488.2 library.
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
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
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,
.
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
2-2 GPIB-488
Chapter 2 Programming with the GPIB Library
Board l/O
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
(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 ibfind
. This 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
Chapter 2 Programming with the GPIB Library
Global Variables
The following global variables are used in all programming languages: ibsta iberr
Status Word
Error Codes ibcnt
, ibcntl
Count Variables (short/long)
The iberr
variables are briefly explained here. For additional information about 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
.
ibcnt and ibcntl—Count Variables
These variables contain an integer which describes how many bytes were actually transferred during a read or write operation. ibcnt
is an integer value (16-bits wide) and ibcntl
is a long integer value (32-bits wide).
2-4 GPIB-488
3
GPIB 488.1 Library Reference
Name
ibask ibeot ibfind ibgts ibist iblines ibln ibloc ibonl ibcac ibclr ibcmd ibcmda ibconfig ibdev ibdma ibeos
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
Description
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
Place device online/offline
GPIB-488 3-1
Name
ibpad ibrsv ibsad ibsic ibsre ibstop ibtmo ibtrg ibwait ibpct ibppc ibrd ibrda ibrdf ibrpp ibrsc ibrsp ibwrt ibwrta ibwrtf
Chapter 3 GPIB 488.1 Library Reference
Table 3-1. 488.1 Library routines (Continued)
Description
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
Wait for event
Write data from a string
Write data asynchronously from a string
Write data from file
3-2 GPIB-488
Chapter 3 GPIB 488.1 Library Reference
IBASK
Returns software configuration information.
Syntax
C ibask (int boarddev, int option, unsigned int
*value)
Parameters
boarddev option value
IbaPAD
Option
IbaSAD
IbaTMO
IbaEOT
IbaPPC
IbaREADDR
IbaAUTOPOLL
IbaCICPROT
IbaSC
IbaSRE
Valid for
bd/dev bd/dev bd/dev bd/dev bd dev bd bd bd bd
A board handle or device handle
Specifies which configuration item to return; see Table.
Current value of specified item returned here
Table 3-2. ibask Options
Information returned
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
Chapter 3 GPIB 488.1 Library Reference
IbaEOSrd
IbaEOSwrt
IbaEOScmp
IbaEOSchar
IbaPP2
IbaTiming
IbaDMA
IbaSendLLO
IbaSPollTime
IbaPPollTime bd
IbaEndBitIsNormal bd
IbaUnAddr
IbaIST
IbaBNA
Option
bd/dev bd bd bd bd dev dev bd dev
Table 3-2. ibask Options (Continued)
Valid for
bd/dev bd/dev bd/dev
Information returned
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
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
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
The individual status (ist) bit of the interface
Device’s access board
3-4 GPIB-488
Returns
Usage notes
Example
C
Chapter 3 GPIB 488.1 Library Reference
ibsta
will contain a 16-bit status word; refer to Appendix B,
.
iberr
will contain an error code if an error occurred value
will contain the current value of selected configuration item
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, ibtmo
, ibeos
, etc.). In that case, ibask
returns the modified version.
Returns the ist
bit of a device at PAD 3.
int dev, istbit; dev = ibdev (0,3,0,13,1,0); ibask (dev, IbaIST, &istbit);
GPIB-488 3-5
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 ibrd
or ibwrt
operation is in progress, the synchronous take control may not occur if a timeout or other error occurs during the ibrd
/ ibwrt
.
In comparison, if the board is to take control asynchronously, it takes control immediately, without waiting for any data transfers to be completed.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
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);
3-6 GPIB-488
Chapter 3 GPIB 488.1 Library Reference
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,
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
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
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,
bytecount
is the number of command bytes to be transferred.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
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. ibcntl
is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead of ibcnt
.
Usage Notes
This routine passes only GPIB commands. It cannot be used to transmit programming instructions (data) to devices. Use the ibrd
and ibwrt
routines for this purpose.
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.
3-8 GPIB-488
Chapter 3 GPIB 488.1 Library Reference
Example
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
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,
. 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,
.
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. ibcntl
is a 32-bit integer. If the requested count was greater than 64 K, use ibcntl instead of 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. ibcmda
executes in the background and the program continues into the WHILE loop. This loop calls ibwait
to update ibsta
and checks ibsta
to see if ibcmda
has 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" ibcmda (board, command, 6); while ( (ibsta & CMPL+ERR) == 0) ibwait (board, 0);
3-10 GPIB-488
Chapter 3 GPIB 488.1 Library Reference
IBCONFIG
Changes configuration parameters.
Syntax
C ibconfig (int boarddev, unsigned int option, unsigned int value)
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.
IbcPAD
Option
IbcSAD
IbcTMO
IbcEOT
IbcPPC
IbcREADDR
Table 3-3. ibconfig Options
Valid for
bd or dev bd or dev bd or dev bd or dev bd dev
Description
New Primary Address. Available primary addresses range from 0 to 30. value
can be from 0 to 30 decimal.
(See ibpad
.)
New Secondary Address. There are 31 secondary addresses available. value
can be 0 or from 96 to 126 decimal. (See 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
Chapter 3 GPIB 488.1 Library Reference
IbcAUTOPOLL
IbcCICPROT
IbcIRQ
IbcSC
Option
IbcSRE
IbcEOSrd
IbcEOSwrt
IbcEOScmp
IbcEOSchar
IbcPP2 bd
Valid for
bd bd bd bd
Table 3-3. ibconfig Options (Continued) bd or dev bd or dev bd or dev bd or dev
Description
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.
7/8-bit Comparison. If value
is zero, compare the low-order 7 bits of the EOS character. Otherwise, compare 8-bits.
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.
3-12 GPIB-488
Chapter 3 GPIB 488.1 Library Reference
Option
IbcTIMING
IbcDMA
IbcSendLLO
IbcSPollTime
IbcUnAddr bd bd
Table 3-3. ibconfig Options (Continued) bd
Valid for
bd or dev
IbcEndBitIsNormal bd or dev
IbcPPollTime bd dev
Description
Handshake Timing. If value
is 1, normal timing (> 2
*sec.) is used. If value
is 2, high-speed timing (> 500 nsec.) is used. If 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,
.
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
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,
iberr
will contain an error code, if an error occurred.
Usage Notes
None.
GPIB-488 3-13
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);
3-14 GPIB-488
Chapter 3 GPIB 488.1 Library Reference
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, int timeout, int eot, int eos)
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,
. 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,
timeouts and corresponding values.
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
, 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
EARG
error is returned if illegal values are given for pad
, sad
, timeout
, eot
, eos
.
iberr
will contain an error code, if an error occurred.
Usage Notes
This routine returns the device handle of the first available user-configurable device it finds in the device list.
GPIB-488 3-15
Chapter 3 GPIB 488.1 Library Reference
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);
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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 dma
is non-zero, all read and write operations between the GPIB board and 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,
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 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 ibdma
call is made.
• ibonl
or ibfind
is called.
• The program is re-started.
• The maximum DMA transfer length in Windows is 64 K bytes.
Example
C
This example enables DMA transfers for GPIB Interface Board 1. It assumes that the DMA channel was previously selected in your configuration program.
int board, ibsta; board = ibfind ("gpib1"); ibsta = ibdma (board, 1);
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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.
A
Method
B
C
Table 3-4. Selecting EOS
Description
Terminate read when EOS is detected. Can be used alone or in combination with Method C. (Constant =
REOS)
Set EOI with EOS on write function. Can be used alone or in combination with Method C. (Constant = XEOS)
Compare all 8 bits of EOS byte rather than low 7 bits for all read and write functions. (Constant = BIN)
eos
High Byte Low Byte
00000100 EOS character
00001000
00010000
EOS character
EOS character
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
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.
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This call remains in effect until one of the following occurs:
• Another ibeos
call is made.
• ibonl
or ibfind
is called.
• The system is re-started.
See also ibeot
Example
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,
used (
XEOS
).
C int device; ibeos (device, XEOS + '\n');
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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 ibfind
routine.
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 eot
is 0, then EOI is not asserted.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
iberr
will contain an error code, if an error occurred.
Usage Notes
This call is used to temporarily change the default EOT setting.
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,
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 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 dmm
. If the device name is not found, the program will jump to an error routine.
C Board = ibfind("GPIB0"); if (Board < 0) error();
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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
Not Ready For Data
(NRFD) handshake 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
END
message and holds off subsequent transfers. Using this mechanism, the GPIB board can take control synchronously on a subsequent operation like ibcmd
or ibrpp
.
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,
.
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). ibgts
is 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+".
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Chapter 3 GPIB 488.1 Library Reference
int gpib1; gpib1 = ibfind ("GPIB1"); ibcmd (gpib1, "?Z+", 3); ibgts (gpib1, 1);
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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 statusbit
= 0, the IST bit is cleared.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
iberr
will contain an error code, if an error occurred. If an error does not occur, the previous
IST value is stored in iberr
.
Usage Notes
This routine is used when the GPIB Interface is not the Active Controller.
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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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:
15
EOI
7
14
ATN
6
13
SRQ
5
12
REN
4
High
11
IFC
3
Low (Mask)
10
NRFD
2
9
NDAC
1
8
DAV
0
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,
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";
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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,
iberr
will contain an error code if an error occurred.
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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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,
.
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
IBLOC
function is used to simulate a front panel RTL switch if the computer is used as an instrument.
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,
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 ibfind
or ibdev routine.
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,
.
iberr
will contain an error code if an error occurred. Contains the previous primary address if no error occurred.
EARG
error occurs if address is out of range.
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.
If a device is specified, its talk and listen addresses are assigned on the basis of address
. Its
Listen Address equals address
+ 20 hex. Its Talk Address equals address
+ 40 hex. Thus, 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
.
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,
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.
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 ibfind
routine.
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:
1
1
1
1
0
7
0
6
1
5
1
4
0
3
SENSE
2
P2
1
P1
0
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
P2
1
1
0
0
1
Table 3-5. Values for P2–P0
P1 P0
1
0
1
0
1
GPIB Data Line
DIO8
DIO7
DIO6
DIO5
DIO4
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0
0
0
P2
1
0
0
Table 3-5. Values for P2–P0
P1 P0
0
1
0
GPIB Data Line
DIO3
DIO2
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
0
6
1
5
1
4
0
3
SENSE
2
P2
1
P1
0
P0
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
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 command
.
If boarddev
specifies a device, the GPIB Interface Board associated with the device 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 bytecount)
Parameters
boarddev
is an integer containing the board or device handle.
buf
is the storage buffer for the data. Up to 4 gigabytes-1 (2
32
-1 bytes) can be stored. String 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,
.
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
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
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.
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
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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IBRDA
Reads data asynchronously from a device/interface board into a string.
Syntax
C ibrda (int boarddev, char buf[], unsigned long bytecount)
Parameters
boarddev
is an integer containing the device/board handle.
buf
is the storage buffer for the data. Up to 4 gigabytes-1 (2
32
-1 bytes) can be stored. String 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,
.
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. ibrda
begins a transfer of 5000 bytes in the background and the program continues on into the WHILE loop. The WHILE loop calls ibwait
with
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]; ibwrt (device, "DUMP"); ibrda (device, readbuffer, 5000); while ( (ibsta & CMPL+ERR) == 0) ibwait (device, 0)
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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,
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
.
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,
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.
Before executing a parallel poll, the ibppc
function should configure the connected devices with ibppc
to specify how they should respond to the poll.
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 ibfind
and 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 ibppc specifies that the first device ( voltmeter
) should drive the DIO1 line high when its first line goes high. The second ibppc
specifies that the second device ( scope
) should drive the DIO2 line high when its first bit goes high. The 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"
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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 control
is non-zero, the specified board becomes the system controller on the GPIB. If control
is 0, the board is not the system controller.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
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.
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,
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 ibsta
is set on that device. In this case ibrsp
returns the previously acquired status byte. If the RQS bit of ibsta
is not set during an automatic poll, it serial polls the 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.
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,
.
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 address
is a legal secondary address (60 to 7E hex), the new secondary address is temporarily assigned to the board/device. The new secondary address is used until it is either redefined by calling ibsad
again, the device/board is re-initialized by calling ibfind
or ibonl
, or the program is restarted.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
iberr
will contain an error code, if an error occurs. Contains the previously assigned secondary address if no error occurs.
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,
.
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
IFC
(Interface Clear) signal for at least 100 µsec. This action results in the system controller regaining control of the GPIB (for example, becoming the Controller-In-Charge). When
IFC
line is asserted, all GPIB interface functions of the bus devices are reset.
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
REN
line is asserted.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
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
REN
state if no error occurs.
Usage Notes
This routine can only be used if the specified GPIB interface board is the system controller.
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,
. If an operation is terminated, the
ERR
bit is set.
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.
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
EABO
error. Valid timeout codes are shown in Table 3-6.
Code
TNONE
T10us
T30us
T100us
T300us
T1ms
T3ms
T10ms
T30ms
5
6
3
4
7
8
0
1
2
Value
Table 3-6. Timeout Codes
Minimum timeout
Disabled
10 msec
30 msec
100 msec
300 msec
1 msec
3msec
10msec
30 msec
Code
T100ms
T300ms
T1s
T3s
T10s
T30s
T100s
T300s
T1000s
12
13
14
15
9
10
11
16
17
Value
Minimum timeout
100 msec
300 msec
1 sec
3 sec
10 sec
30 sec
100 sec
300 sec
1000 sec
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
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 ibfind
or ibonl
); or the system is restarted.
Example
This example changes the timeout (to 30 sec) for all calls specifying the "plotter" device at
PAD 3.
C int plotter; 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,
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; 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 ibsta
positions.
Bit
Event
15
ERR
14
TIMO
13
END
12
SRQI
11
RQS
10 9 8
CMPL
Bit
Event
7
LOK
6
REM CIC
5 4
ATN
3
TACS
2
LACS
1
DTAS
0
DCAS
For more information regarding ibsta
.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
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
TIMO
is set, ibwait
returns 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.
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Example
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 bytecount)
Parameters
boarddev
is an integer containing the board or device handle.
buf
is the string containing the data to be written. buf
can contain up to 4 gigabytes-1 (2
32
-1 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,
.
iberr
will contain an error code of the first error detected, if an error occurred. An
EADR results if boarddev
specifies a board and the board has not already been addressed to talk.
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.
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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If you want to send an EOS character at the end of the data string, you must include it in the string.
Example
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 bytecount)
Parameters
boarddev
is an integer containing the board or device handle.
buf
is the storage buffer for the data. Up to 4 gigabytes-1 (2
32
-1 bytes) can be stored. 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.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
.
iberr
will contain an error code of the first error detected, if an error occurred. An
EADR results if boarddev
specifies a board and the board has not already been addressed to talk.
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. ibwrta
begins a transfer of 5000 bytes in the background and program continues on into the WHILE loop. The WHILE loop calls ibwait
with MASK set to 0 to update ibsta
. The WHILE loop checks ibsta
to see if ibwrta
has completed or any error have occurred. The program may do anything else within the WHILE loop except make other GPIB I/O calls.
C char writebuffer[5000]; 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,
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
.
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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4
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.
HIGH BYTE
Secondary Address (0 or 96-126)
Table 4-1. 488.2 Address word
LOW BYTE
Primary Address (0-30)
488.2 routines use a board index as the first argument (typically zero) – not a handle.
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AllSpoll
Performs a serial poll on specified devices.
Syntax
C AllSpoll (int board, short addresslist[], short resultlist[])
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,
.
iberr
will contain an error code, if an error occurred. If a device times out, iberr
contains
Error 6 –
EABO
), 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,
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.
To clear multiple devices, use the
DevClearList
routine.
If address
is set to
NOADDR
, then all connected devices on the GPIB is cleared through the
Universal
Device Clear
(UDC) message.
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,
.
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,
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
Go To Local
(GTL) command.
To put all devices in local mode, use an array containing only the
NOADDR
value. This unasserts the GPIB
Remote Enable
(REN) line, thereby placing all GPIB devices in local mode.
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,
.
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 resultlist[], int limit)
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,
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 resultlist
. In this case, ibcnt
contains the number of addresses actually placed in resultlist
.
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
*result)
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,
.
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, ibcn t contains
NOADDR
's index.
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.
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 address
is 0.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
iberr
will contain an error code, if an error occurred.
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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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
PPollConfig
and the individual status of the devices.
ibsta
will contain a 16-bit status word as described in Appendix B,
.
iberr
will contain an error code, if an error occurred.
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 dataline, int sense)
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 sense
= 0 and the device asserts the specified data line 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,
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,
.
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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Chapter 4 GPIB 488.2 Library Reference
RcvRespMsg
Reads data from a previously addressed device.
Syntax
C RcvRespMsg(int board, char data[], long count, int termination)
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 termination
=
STOPend
(A constant defined in the header file), then the read is stopped when EOI is detected.
Returns
data
is the string that receives the data. ibsta
will contain a 16-bit status word as described in Appendix B,
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)
GPIB-488 4-13
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
*result)
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,
.
iberr
will contain an error code, if an error occurred.
Usage Notes
None.
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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Chapter 4 GPIB 488.2 Library Reference
Receive
Reads data from a GPIB device.
Syntax
C Receive(int board, int address,char data[], unsigned long count, int termination)
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 termination
=
STOPend
(constant defined in the header file), then the read is stopped when EOI is detected.
Returns
data
is the string that receives the data.
ibsta
will contain a 16-bit status word as described in Appendix B,
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);
GPIB-488 4-15
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,
.
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
ReceiveSetup
, then make multiple calls of
RcvRespMsg
to transfer the data.
For typical cases,
Receive
is simpler to use, since it takes care of both the setup and the data 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);
4-16 GPIB-488
Chapter 4 GPIB 488.2 Library Reference
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,
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).
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 addresslist
.
This resets the devices to specific parameters.
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[], long count, int eotmode)
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,
.
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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Chapter 4 GPIB 488.2 Library Reference
SendCmds
Send GPIB commands.
Syntax
C SendCmds (int board, char commands[], unsigned 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.
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,
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.
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, int eotmode)
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,
.
iberr
will contain an error code, if an error occurred.
Usage Notes
This routine assumes that the desired GPIB listeners have already been addressed (by using
SendSetup
, for example).
Values for 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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Chapter 4 GPIB 488.2 Library Reference
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,
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).
Example
Clears the GPIB bus from Board 0.
C SendIFC(0);
GPIB-488 4-21
Chapter 4 GPIB 488.2 Library Reference
SendList
Sends data to multiple GPIB devices.
Syntax
C SendList(int board, short addresslist[], char data[], long count, int eotmode)
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,
.
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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Chapter 4 GPIB 488.2 Library Reference
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,
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.
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,
.
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);
4-24 GPIB-488
Chapter 4 GPIB 488.2 Library Reference
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,
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.)
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);
GPIB-488 4-25
Chapter 4 GPIB 488.2 Library Reference
TestSRQ
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,
.
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 */}
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Chapter 4 GPIB 488.2 Library Reference
TestSys
Activate self-test procedures of specified devices.
Syntax
C SendSetup(int board, short addresslist [], short resultlist[])
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.
ibsta
will contain a 16-bit status word as described in Appendix B,
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);
GPIB-488 4-27
Chapter 4 GPIB 488.2 Library Reference
Trigger
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,
.
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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Chapter 4 GPIB 488.2 Library Reference
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
NOADDR
, all previously addressed listeners are triggered.
Returns
ibsta
will contain a 16-bit status word as described in Appendix B,
iberr
will contain an error code, if an error occurred.
Usage Notes
Use
Trigger
to trigger only one device.
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);
GPIB-488 4-29
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, result
= 1. Otherwise, result
= 0. ibsta
will contain a 16-bit status word as described in Appendix B,
.
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
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)}
4-30 GPIB-488
A
Multiline Interface Messages
11
12
13
14
7
8
9
10
5
6
3
4
0
1
2
DEC
15
16
17
18
19
20
0B
0C
0D
0E
07
08
09
0A
03
04
05
06
00
HEX
01
02
0F
10
11
12
13
14
Table A-1. Multiline Interface Messages (Hex 00-3F)
ASCII
NUL
SOH
STX
SI
DLE
DC1
DC2
DC3
DC4
VT
FF
CR
SO
BEL
BS
HT
LF
ETX
EOT
ENQ
ACK
MSG
GTL
SDC
PPC
GET
TCT
LLO
DCL
2B
2C
2D
2E
27
28
29
2A
23
24
25
26
20
HEX
21
22
2F
30
31
32
33
34
43
44
45
46
39
40
41
42
35
36
37
38
32
DEC
33
34
47
48
49
50
51
52
1
2
/
0
3
4
-
>
+
‘
)
*
‘
(
%
&
#
$
!
“
ASCII
SP
MLA7
MLA8
MLA9
MLA10
MLA11
MLA12
MLA13
MLA14
MSG
MLA0
MLA1
MLA2
MLA3
MLA4
MLA5
MLA6
MLA15
MLA16
MLA17
MLA18
MLA19
MLA20
GPIB-488 A-1
Appendix A Multiline Interface Messages
1A
1B
1C
1D
1E
1F
15
HEX
16
17
18
19
26
27
28
29
30
31
21
DEC
22
23
24
25
Table A-1. Multiline Interface Messages (Hex 00-3F) (Continued)
ASCII
NAK
SUB
ESC
FS
GS
RS
US
SYN
ETB
CAN
EM
MSG
PPU
SPE
SPD39
35
36
37
38
39
3F
HEX
3A
3B
3C
3D
3E
58
59
60
61
62
63
53
DEC
54
55
56
57
<
=
;
:
>
?
8
9
6
7
5
ASCII MSG
MLA21
MLA22
MLA23
MLA24
MLA25
MLA26
MLA27
MLA28
MLA29
MLA30
UNL
40
HEX
41
42
43
44
45
46
64
DEC
65
66
67
68
69
70
Table A-2. Multiline Interface Messages (Hex 40-7F)
ASCII
@
MSG
MTA0 60
HEX
96
DEC
‘
ASCII
A
B
C
D
E
F
MTA1
MTA2
MTA3
MTA4
MTA5
MTA6
61
62
63
64
65
66
97
98
99
100
101
102 a b c d e f
MSG
MSA0,P
PE
MSA1,P
PE
MSA2,P
PE
MSA3,P
PE
MSA4,P
PE
MSA5,P
PE
MSA6,P
PE
A-2 GPIB-488
Appendix A Multiline Interface Messages
47
HEX
48
49
4A
4B
4C
4D
4E
4F
50
51
52
53
54
55
56
71
DEC
Table A-2. Multiline Interface Messages (Hex 40-7F) (Continued)
G
ASCII MSG
MTA7 67
HEX DEC
103 g
ASCII
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
MTA8
MTA9
MTA10
MTA11
MTA12
MTA13
MTA14
MTA15
MTA16
MTA17
MTA18
MTA19
MTA20
MTA21
MTA22
68
69
6A
6B
6C
6D
6E
6F
70
71
72
73
74
75
76
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118 t l j i h k m n o p q r s u v
MSA18,
PPD
MSA19,
PPD
MSA20,
PPD
MSA21,
PPD
MSA22,
PPD
MSA14,
PPE
MSA15,
PPE
MSA16,
PPD
MSA17,
PPD
MSG
MSA7,P
PE
MSA8,P
PE
MSA9,P
PE
MSA10,
PPE
MSA11,
PPE
MSA12,
PPE
MSA13,
PPE
GPIB-488 A-3
Appendix A Multiline Interface Messages
57
HEX
58
59
5A
5B
5C
5D
5E
5F
87
DEC
Table A-2. Multiline Interface Messages (Hex 40-7F) (Continued)
ASCII
W
MSG
MTA23 77
HEX DEC
119 w
ASCII
88
89
90
91
92
93
94
95
\
X
Y
Z
[
]
^
_
MTA24
MTA25
MTA26
MTA27
MTA28
MTA29
MTA30
UNT
78
79
7A
7B
7C
7D
7E
7F
120
121
122
123
124
125
126
127
| x y z
{
}
~
DEL
MSG
MSA23,
PPD
MSA24,
PPD
MSA25,
PPD
MSA26,
PPD
MSA27,
PPD
MSA28,
PPD
MSA29,
PPD
MSA30
MSA0
DCL
GET
GTL
LLO
MLA
MSA
Device Clear
Group Execute
Trigger
Go To Local
Local Lockout
My Listen
Address n
My Secondary
Address
Table A-3. Message definitions (MSG column)
MTA
PPC
PPD
PPE
PPU
SDC
My Talk Address
Parallel Port
Configure
Parallel Poll
Disable
Parallel Port
Enable
Parallel Port
Unconfigure
Selected Device
Clear
SPD
SPE
TCT
UNL
UNT
Serial Poll Disable
Serial Port Enable
Take Control
UnListen
UnTalk
A-4 GPIB-488
B
IBSTA
Bit
Hex
Value
15
ERR
8000
Every GPIB library routine returns a 16-bit status word to the variable ibsta
. This status word describes the current condition of the GPIB bus lines and the GPIB Interface Board. By examining the status word, the programmer may determine what path the application program is to take.
Note that the mnemonics used to describe each bit of the status word are defined within the header file for each language.
The status word contains 16-bits. If a bit equals 1 (set), the corresponding condition is true. Likewise, if a bit equals 0, then the corresponding condition has not occurred. The status word is of the following format:
14
TIMO
4000
13
END
2000
12
SRQI
1000
11
RQS
800
10 9 8
CMPL
100
Bit
Hex
Value
7
LOK
80
6
REM
40
5
CIC
20
4
ATN
10
3
TACS
8
2
LACS
4
1
DTAS
2
0
DCAS
1
GPIB-488 B-1
Appendix B IBSTA
ERR
TIMO
Bit
END (END)
SRQI
Table B-1. Bit Definitions
Description
GPIB Error. If this bit = 1, an error has occurred during the call. An error code describing the exact error is returned to the iberr
variable. See
for more information. ERR is cleared following any call
that does not result in an error.
Check for errors after each call. If an undetected error occurs early in your program, it may not be apparent until later in the program, when it is more difficult to isolate.
Timeout Error. If this bit = 1, a time-out has occurred. Some of the conditions which may result in this are:
A synchronous I/O function exceeds the programmed timeout.
An ibwait
has exceeded the time limit value.
This bit is cleared (set to 0) during all other operations.
Different timeout periods may be set for each device. You can set the timeout values either by using the configuration utility or in your program by using the ibtmo
function.
END or EOS Detected. If this bit = 1, EOI has been asserted or an EOS byte has been detected. If the GPIB Interface board has been programmed through an ibgts
to perform shadow handshaking, any other routine can set this bit to one.
This bit is cleared (set to 0) whenever an I/O operation is initiated.
SRQ Interrupt Received. If this bit = 1, a device or Controller is requesting service. This bit is set upon the following conditions:
• The GPIB Interface Board is the Active
Controller.
• The GPIB SRQ line is asserted.
• Automatic serial poll capability is disabled.
This bit is cleared (= 0) upon the following conditions:
• The GPIB Interface Board is no longer the Active
Controller.
• The GPIB SRQ line is unasserted.
B-2 GPIB-488
RQS
Bit
CMPL
LOK
REM
CIC
ATN
Appendix B IBSTA
Table B-1. Bit Definitions (Continued)
Description
Device Requesting Service. If this bit = 1, a device is requesting service. RQS is set in the status word whenever the hex 40 bit is asserted in the serial poll status byte of the device. The serial poll that obtained the status byte may have been the result of an ibrsp
or the poll may have been automatically performed if automatic serial polling is enabled. RQS is cleared when an ibrsp
reads the serial poll status byte that caused the RQS. An ibwait
on RQS should only be done on devices that respond to serial polls.
I/O Completed. When set, this bit indicates that all I/O operations have been completed. CMPL is cleared while I/O is in progress.
Lockout State. Indicates whether the board is in a lockout state. While LOK is set, the
EnableLocal
routine or ibloc
function is inoperative for that board.
LOK is set whenever the GPIB board detects the Local Lockout (LLO) message has been sent either by the GPIB board or another Controller. LOK is cleared when the Remote Enable (REN) GPIB line becomes unasserted by the system controller.
Remote State. If this bit = 1, the GPIB Interface Board is in the remote state
(i.e, the REN line has been asserted and the Board has been addressed as a listener.). This bit is cleared when one of the following occurs:
• REN is unasserted.
• The GPIB Interface Board has been addressed as a
Listener and receives a GTL (Go to Local) command.
•
IBLOC
is called while the LOK bit = 0.
Controller-In-Charge. If this bit = 1, it indicates that the GPIB Interface Board is the Active Controller. This bit is set upon the following conditions:
• If the board is the system controller and ibsic
or
SendIFC
is executed.
• Control is passed to the GPIB Interface Board.
• This bit is cleared whenever the GPIB board detects Interface Clear (IFC) from the system controller, or when the GPIB board passes control to another device.
Attention. If this bit = 1, ATN is asserted. Likewise, if this bit = 0, the ATN line is unasserted.
GPIB-488 B-3
Appendix B IBSTA
TACS
Bit
LACS
DTAS
DCAS
Table B-1. Bit Definitions (Continued)
Description
Talker. If this bit = 1, the GPIB Interface Board has been addressed as a talker.
This bit is cleared when one of the following occurs:
• The UNT command is sent.
• The GPIB Interface Board is sent its listen address.
• Another talker is addressed.
• IFC is asserted.
Listener. If this bit = 1, the GPIB Interface Board has been addressed as a
Listener. It can also be set if the GPIB Interface Board shadow handshakes (as a result of an ibgts
). This bit is cleared whenever one of the following occurs:
• The GPIB Interface Board receives an UNL
(Unlisten) command.
• The GPIB Interface Board is addressed as a talker.
• ibgts
is called disabling shadow handshaking.
Device Trigger Status. If this bit = 1, a GET (Group Execute Trigger) command has been detected. This bit is cleared in the status word on any call immediately following an ibwait
if the DTAS bit is set in the ibwait
mask parameter.
Device Clear State. If this bit = 1, a DCL (Device Clear) or SDC (Selected
Device Clear) command has been received by the GPIB Interface Board. The bit is cleared on any call immediately following an ibwait
call if the DCAS bit was set in the ibwait
mask parameter, or on any call immediately following a read or write.
Some of the status word bits can also be cleared under the following circumstances:
• If ibonl
is called, the
END
,
LOK
,
REM
,
CIC
,
TACS
,
LACS
,
DTAS
, and
DCAS
bits are cleared.
• If an
ENEB
or
EDVR
error is returned (See
for more information.), all of the status word bits except ERR are cleared.
B-4 GPIB-488
C
IBERR
If the ERR bit in the status word ( ibsta
) has been set (= 1), an error code describing the exact error is returned to the iberr
the possible GPIB error codes, the corresponding mnemonic, and a brief explanation. Note that the mnemonics are defined within the header files for each language. This allows you to use the mnemonic in place of the error code value. Detailed explanations of each error and possible solutions are listed after the table.
Table C-1. Error codes
12
14
15
16
6
7
10
11
4
5
2
3
0
1
Error Code
Decimal Mnemonic
EDVR
ECIC
ENOL
EADR
EARG
ESAC
EABO
ENEB
EOIP
ECAP
EFSO
EBUS
ESTB
ESRQ
Description
System error
Function requires GPIB board to be CIC
Write function detected no Listeners
Interface board not addressed correctly
Invalid argument to function call
Function requires GPIB board to be SAC
I/O operation aborted
Non-existent interface board
I/O operation started before previous operation completed
No capability for intended operation
File system operation error
Command error during device call
Serial poll status byte lost
SRQ remains asserted
GPIB-488 C-1
Appendix C IBERR
Table C-1. Error codes (Continued)
20
23
Error Code
Decimal Mnemonic
ETAB
EHDL
The return buffer is full.
The input handle is invalid
Description
Cause:
Solution:
EDVR—Driver error
A board or device is not installed or configured properly. This error is returned when a device or board that is passed to ibfind
cannot be found, or when a board index passed to ibdev
cannot be found. ibcntl
will contain an error code to help further identify the problem.
• Call ibdev
to open a device without using its symbolic name.
• Configure each board and device.
• Include the unit descriptor that is returned from ibfind or ibdev
as the first parameter in the function. Verify that the value of the variable before the failing function is not corrupted.
Cause:
Solution:
ECIC—Specified GPIB interface board is not CIC
Many routines require that the GPIB interface board is the
Controller-In-Charge. These include: ibcmd
, ibln
, ibrpp
,
Send
,
Receive
, for example, as well as any routines which manipulate the
GPIB ATN, EOI, or REN lines.
Make sure that the GPIB interface board is the Controller-In-Charge.
C-2 GPIB-488
Cause:
Solution:
Cause:
Solution:
Cause:
Solution:
Cause:
Solution:
Appendix C IBERR
ENOL—No listening device(s)
The routine detected no listeners.
Verify the following:
• Make sure that a device has been addressed properly.
• Check that at least two-thirds of the devices on the GPIB bus are turned on, including the specified device.
• Make sure that all connections are secure.
• Verify the device(s) GPIB address.
• Make sure that the device was properly configured.
EADR—GPIB interface board not addressed
The GPIB interface board has not been addressed.
Call ibcmd
and address the board.
If you are calling ibgts
, with shadow handshaking enabled, call ibcac
.
EARG—Invalid argument
An invalid parameter has been provided to a routine.
Check syntax and range of parameters. See Chapter 3,
ESAC—Board is not the system controller
Routine requires that the GPIB interface board is the system controller.
Configure the board to be the system controller.
GPIB-488 C-3
Appendix C IBERR
Cause:
Solution:
Cause:
Solution:
Cause:
Solution:
Cause:
Solution:
EABO—I/O operation aborted
I/O operation aborted. (time-out)
Check that the device is powered on.
Verify proper cable connections.
ENEB—Non-existent GPIB board
GPIB board is not recognized.
Make sure that GPIB board settings and configuration setup parameters agree.
EOIP—Function not allowed while I/O is in progress
An illegal call is made during an asynchronous I/O operation.
Only ibstop
, ibwait
, and ibonl
calls are allowed during asynchronous I/O operations. The driver must be resynchronized by calling one of the following:
• ibwait
(mask contains
CMPL
)—The driver and application are synchronized.
• ibstop
—The asynchronous I/O is canceled, and the driver and application are synchronized.
• ibonl
—The asynchronous I/O is canceled, the interface is reset, and the driver and application are synchronized.
Re-synchronization is successful if a CMPL is returned to ibsta
.
ECAP—No capability for operation
A call attempts to use a capability which is not supported by the
GPIB board.
Don't use the call.
C-4 GPIB-488
Cause:
Solution:
Cause:
Solution:
Cause:
Solution:
Appendix C IBERR
EFSO—File system error
A problem was encountered while performing a file operation.
Verify the following:
• Make sure that you specified the correct filename.
• Check the spelling and the path.
• If you need more room on the disk, delete some files.
• Verify that you did not assign a name to a device which is already used by a file.
EBUS—Command byte transfer error
A GPIB bus error occurs during a device function.
• Determine which device, if any, is abnormally slow to accept commands and fix the problem with the device.
• Lengthen the assigned time limit using ibtmo
or ibconfig
.
ESTB—Serial poll status byte(s) lost
One or more serial poll status bytes received during an automatic serial poll was lost.
Call ibrsp
more frequently to read the status bytes. Ignore the
ESTB error.
Note: This error occurs only during ibrsp
functions.
GPIB-488 C-5
Appendix C IBERR
Cause:
Solution:
Cause:
Solution:
Cause:
Solution:
ESRQ—SRQ in "ON" position
A wait for an RQS can not occur because the GPIB SRQ line is ON.
Verify the following:
• Ignore the ESRQ until all devices are found.
• Make sure ibdev
is called to open all devices on the bus capable of asserting SRQ.
• Test that each device is unasserting SRQ.
• Check the cabling. Make sure that all devices are attached and the connectors are seated properly.
ETAB—Table problem
There was a problem with a table used in a
FindLstn
or
FindRQS
.
• If the error occurs during a
FindLstn
, this is a warning and not an error. Ignore the warning or make the buffer larger.
• If the error occurs during a
FindRQS
, then none of the specified devices are requesting services. Verify that the device list contains the addresses of all online devices.
EHDL—Invalid handle
EHDL results when an invalid handle is passed to a function call.
• Do not use a device descriptor in a board function or vice-versa.
• Make sure that the board index passed to the call is valid.
C-6 GPIB-488
Index
Numerics
488.1
library reference (table), 3-1
library routines
IBASK, 3-3 options (table), 3-3
IBCONFIG, 3-11 options (table), 3-11
IBEOS, 3-18 selecting EOS (table), 3-18
IBPAD, 3-30
IBPPC, 3-32 values for P2-P0 (table), 3-32
GPIB-488 I-1
IBTMO, 3-47 timeout codes (table), 3-47
488.2
library reference (table), 4-1
library routines
Index
A
B
C
conventions used in the manual, iii
count variables (ibcnt and ibcntl), 2-4
D
device handles (programming), 2-3
device I/O (programming), 2-2 device versus I/O (programming), 2-2
documentation
conventions used in the manual, iii
E
F
I-2
G
GPIB
488.1 library reference (table), 3-1
488.2 library reference (table), 4-1
library utility programs, 1-2 ibnotify, 1-2 support for VISA calls, 1-2
GPIB-32.DLL function support, 1-2
I
IBASK, 3-3 options (table), 3-3
IBCONFIG, 3-11 options (table), 3-11
IBEOS, 3-18 selecting EOS (table), 3-18
IBPAD, 3-30
GPIB-488
IBPPC, 3-32 values for P2-P0 (table), 3-32
IBTMO, 3-47 timeout codes (table), 3-47
L
languages supported (table), 1-1
library reference (GPIB 488.1, table), 3-1
library reference (GPIB 488.2, table), 4-1
library utility programs
M
multiline interface messages
message definitions (MSG column),
GPIB-488 I-3
P
programming
board I/O, 2-3 device handles, 2-3
device I/O, 2-2 device versus board I/O, 2-2 general concepts, 2-2
ibcnt and ibcntl (count variables), 2-4 iberr (error variable), 2-4
languages supported (table), 1-1
R
S
software
GPIB-32.DLL function support, 1-2
overview, 1-1 supported languages (table), 1-1
Index
Index
supported languages (table), 1-1
T
U
W
I-4 GPIB-488
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