Recall Device Errors - Fluke 8508A User Manual

8508A
Users Manual
A device-dependent error (DDE) is generated if the device detects an internal operating
fault (e.g., during self-test). The DDE bit (3) is set true in the Standard-defined Event
Status Byte, and the error code number is appended to the Device-Dependent Error
queue.
In remote operations, the error is reported by the mechanisms described in the section
which deals with status reporting, and the queue entries can be read destructively as LIFO
by the query command DDQ?. The remote user can ignore the queue, but it is good
practice to read the errors as they occur.
In local (front panel) operations, the DDE status is checked at the end of the operation
(e.g., Cal, Zero, Test). If true, an error has occurred, and the content of the last entry in
the queue is displayed on the front panel. The local user cannot continue until the queue
has been read.
If both bus and front panel users attempt to read the queue concurrently, the error data is
read out destructively on a first-come, first-served basis. Thus one of the users cannot
read the data on one interface as it has already been destroyed by reading on the other.
This difficulty should be solved by suitable application programming to avoid the
possibility of a double readout. Ideally the IEEE 488 interface should set the instrument
into
The code numbers for device dependent errors, with their associated descriptions, are
given in Appendix A.

Recall Device Errors

DDQ?
Recalls the last error from the queue of device-dependent errors (e.g., errors recorded
during a failed selftest). The queue is organized as a last-in - first-out stack, its individual
entries being destructively read. If there are no entries in the queue, then use of this
command generates a result of 0.
Read the queue until empty. To prevent unrelated history of errors being
retained, read the queue until empty on each occurrence of a device­
dependent error.
Response
(Nr1) The value returned is a specified integer value indicating the fault.
Recall Execution Errors
4-32
or to prevent confusion.
REMS RWLS
DDQ?

Recall Device Errors

Note
EXQ?
Recall Execution Error
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