Error Messages; Command Timing; Sequential/Overlapped Commands; Query Response Timing - ILX Lightwave MPS-8033 Series User Manual

Error Messages

Error messages may appear on the 8033 display when error conditions occur which force the output
off or reflect hardware errors in the 8033. These errors are also held internally for retrieval via GPIB.
The error queue can be read by issuing the "ERR?" command. This command returns a string
containing up to ten error messages from the error message queue.
If "ERR?" is sent when the error queue is empty an ASCII zero (0) is returned. If the error queue is
NOT empty then bit #7 in the Status Byte is set to one (1).
Refer to Appendix A, Error Messages on page 83 for an explanation of the error messages that are
reported remotely by the 8033.

Command Timing

This section describes, for each device−dependent command, whether that command is performed
in an overlapped or sequential manner. In other words, it states whether the next command may
begin while this command is being executed, or if the next command must wait until this command is
completed before its execution begins. See Operation Complete Definition on page 30 for conditions
about setting the operation complete flag.

Sequential/Overlapped Commands

All device−dependent commands are executed in an overlapped manner: subsequent commands
may begin before the current command is completed. Some common commands are sequential; the
next command must wait until this command is completed. All device−dependent commands are
executed in an overlapped manner, except the "DELAY" command which is sequential. The
operation complete flag is set after the conditions outlined in the Operation Complete Definition have
been satisfied.
The *WAI (common command) is an example of a sequential command which forces the next
command to wait until the no−operation−pending flag is true. This is essentially the same as waiting
for the OPC flag to become true, because the no−operations−pending flag is used to set the OPC flag
(bit 0 of the Standard Event Status Register).
Commands which change the status of the instrument limits, or change its mode or current range,
step value, or status enable registers, will not have their OPC flag set until all current writing to non−
volatile memory has been completed. This ensures the OPC flag is never set prematurely.

Query Response Timing

Query responses are evaluated at the time the query request is parsed, and not at the time the
response message is sent. In most cases this does not create a problem since the time between
parsing a query and sending its response is small.

Input Buffer and Output Data

The Input buffer of the 8033 is 80 bytes. However, the <PROGRAM MESSAGE> may be longer.
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Error Messages
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C H A P T E R
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