Chapter 7
ibconf–Interface Bus Configuration Utility
© National Instruments Corp.
7-7
NI-488.2M UM for Windows NT
Set EOI with
Some devices expect the GPIB EOI line to be asserted when the EOS
EOS on Write byte is transferred. When this field is selected, the NI-488.2M software
asserts the GPIB EOI line whenever it sends the EOS byte. By default
this option is not selected.
8-bit EOS
When the GPIB board is configured to use the EOS byte, it can test
Compare
either seven or eight bits of the EOS byte for a match. When this item
is selected, the NI-488.2M software uses all eight bits of the EOS byte
when checking for a match. By default this option is not selected.
Send EOI at
Many GPIB devices require the GPIB EOI line to be asserted at the end
end of Write
of a data transfer. This signals the device that the transfer has ended.
When this item is selected, the NI-488.2M software will assert the EOI
line at the end of each data transfer. By default this option is selected.
EOS Byte
If one or more of the EOS modes are enabled, this value defines the
EOS byte. Use a decimal number in the range 0 to 255. The value is
used by the NI-488.2M software for all selected EOS operations.
System
The System Controller in a GPIB system is the device that maintains
Controller
ultimate control over the bus. When the NI-488.2M software is being
used to control a GPIB system, the GPIB interface board should
normally be the System Controller. Some situations, such as a network
of computers, require that the interface board not be the System
Controller. By default this option is selected.
I/O Timeout
Use this option to select the timeout value for all GPIB I/O operations.
The timeout value is the approximate length of time that GPIB
functions wait for data to be transferred or commands to be sent. It is
also the length of time that the
ibwait
function waits for an event
before returning. The default timeout period is 10 s.
Parallel Poll
Use this option to select the length of time the NI-488.2M software
Duration
waits when conducting a parallel poll. For a normal bus configuration
(the Controller and devices on the same bus) use the default duration of
2
µ
s. If you are using a GPIB bus extender in transparent parallel poll
mode, you should increase the poll duration to 10
µ
s or more so the bus
extender can operate transparently to your applications.
Enable Auto
Use this option to enable or disable the automatic serial polling of
Serial Polling
devices when the GPIB Service Request (SRQ) line is asserted.
Positive poll responses are stored by the NI-488.2M software and can
be retrieved with the
ibrsp
function. This feature usually does not
conflict with any device that conforms to the IEEE 488.1 standard. If a
conflict exists with a device, do not select this option. By default this
option is selected.
