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Appendix B
ESTB (15)
ESTB occurs only during the ibrsp function. ESTB indicates that auto
polling was not done for a device whose serial poll response queue was full.
Several older status bytes are available; however, the oldest is being
returned by the ibrsp call.
Solutions
1.
Call ibrsp more frequently to empty the queue.
2.
Disable autopolling with the ibconfig function or the ibconf
utility.
ESRQ (16)
ESRQ occurs only during the WaitSRQ routine or ibwait function.
ESRQ indicates that the GPIB SRQ line is stuck on. This situation can be
caused by the following events:
•
Usually, a device unknown to the software is asserting SRQ. Because
the software does not know of this device, it can never serial poll the
device and unassert SRQ.
•
A GPIB bus tester or similar equipment might be forcing the SRQ line
to be asserted.
•
A cable problem, involving the SRQ line, might exist.
•
The serial poll response queue of a device that is asserting the SRQ line
is full.
Although the occurrence of ESRQ warns you of a definite GPIB problem, it
does not affect GPIB operations, except that you cannot depend on the RQS
bit while the condition lasts.
Solutions
1.
Check to see whether other devices not used by your application are
asserting SRQ. Disconnect them from the GPIB if necessary.
2.
Call ibrsp for the device whose serial poll queue is full.
© National Instruments Corp.
Error Codes and Solutions
B-9
NI-488.2M SRM for OS/2
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