National Instruments NI-488.2 - Manual (Page 112)

Appendix C Error Codes and Solutions
NI-488.2 User Manual C-8 ni.com
• Make sure that the access mode of the file is correct.
• Make sure there is enough room on the disk to hold the file.
EBUS (14)
EBUS results when certain GPIB bus errors occur during device functions.
All device functions send command bytes to perform addressing and other
bus management. Devices are expected to accept these command bytes
within the time limit specified by the default configuration or the
IbcTMO
option in the ibconfig function. EBUS results if a timeout occurred while
sending these command bytes.
EBUS can occur if there are no functioning devices present on the GPIB.
Solutions
Possible solutions for this error are as follows:
• Verify that the instrument is operating correctly.
• Check your cable connections and make sure at least two-thirds of
your devices are powered on.
• If the timeout period is too short for the driver to send command bytes,
increase the timeout period.
ESRQ (16)
ESRQ can only be returned by a device-level ibwait call with RQS set in
the mask. ESRQ indicates that a wait for RQS is not possible because 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 might exist involving the SRQ line.
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
Ibsta RQS bit while the condition lasts.