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ibconf—Interface Bus Configuration Utility
Chapter 7
Primary GPIB Address
All devices and boards must be assigned a unique primary address in the range
hex 00 to hex 1E (0 to 30 decimal). The default primary address of all GPIB
boards is 0.
The GPIB primary address of any device is set within the device, either with
hardware switches or a software program. The address set within the device
must correspond to the address in the memory-resident driver. In the NI-488.2M
driver for OS/2, the default primary addresses of dev1 through dev32 are 1
through 32, respectively. Refer to the device documentation for instructions
about setting the device address. GPIB boards do not have hardware switches to
select the GPIB address.
The primary GPIB address is used to compute the talk and listen addresses of
devices and boards. The NI-488.2M driver automatically forms a listen address
by adding hex 20 to the primary address and a talk address by adding hex 40 to
the primary address. For example, a primary address of hex 10 has a listen
address of hex 30 and a talk address of hex 50.
Secondary GPIB Address
Any device or board using extended addressing must be assigned a secondary
address in the range hex 60 to hex 7E (96 to 126 decimal), or the option NONE
may be selected to disable secondary addressing.
As with primary addressing, the secondary GPIB address of a device is set within
that device, either with hardware switches or a software program. The address
set within the device must correspond to the address in the memory-resident
driver. Refer to the device documentation for instructions about secondary
addressing. The default setting for this characteristic is NONE for all boards and
devices.
Timeout Setting
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, if the TIMO bit is set
in the event mask. For example, if the SRQI bit and TIMO bit in the event mask
are passed to the ibwait function and no SRQ is detected, the function
timeouts after the duration given by the timeout setting value. The default option
for this characteristic is 10 s.
NI-488.2M SRM for OS/2
7-10
© National Instruments Corp.
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