Command Timing; Sequential / Overlapped Commands; Query Response Timing - ILX Lightwave LDX-36000 Series User Manual

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 the first is being executed, or if
it must wait until the first command is completed before its execution begins. See
the Operation Complete Definition earlier in this chapter 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 has completed.
Some common commands are sequential; the next command must wait until this
command has 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 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,
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.
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R E M O T E O P E R A T I O N
Command Timing
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C H A P T E R
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LDX-36000 Series
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