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Remote Operation
Getting Started
Remote command buffering
The OSA accepts serial data via HP-IB, testing each byte. Once a complete
command is received and interpreted, the HP-IB handshake is held until the
command operation is completed. Once completed, the next command byte is
read by the analyzer. If several commands are included in a single output
statement, the computer will not be able to complete the controller output
operation until the OSA has executed all of the commands. This process can
hold the HP-IB interface, or program control, past a timeout cycle.
For this reason, send individual commands rather than combining them. After
the command is correctly interpreted, the bus is held until the command exe-
cution is complete. If there are no other commands pending, the interface bus
is released and the controller can perform other tasks while the OSA is com-
pleting the operation.
Command buffering provides an automatic synchronization between the pro-
gram sending the commands and the analyzer operation. Each command will
be executed before another command is recognized. There is no danger of
reading or interpreting trace data in an indeterminate state, such as before a
sweep has completed.
Controlling the sweep
Placing the optical spectrum analyzer in remote mode and sending the
DISP:WIND:TRAC:ALL:SCAL:AUTO command finds the largest signal and
optimizes the analyzer settings. This command also sets single sweep mode on
the analyzer. If the DISP:WIND:TRAC:ALL:SCAL:AUTO command is not used,
single sweep can be set using the INIT:CONT OFF command. The trace data
present in the analyzer must be updated by taking a sweep when appropriate
using the INIT:IMM command. Use this command to update the sweep after
changing settings.
This mode of operation allows the program to control the sweep and ensure
that data read from, or operated on in the analyzer, is updated correctly. Con-
trolling the sweep also minimizes the amount of time the analyzer spends
sweeping. At high sensitivity and high resolution settings, sweeps can take a
significant amount of time. Controlling the sweep ensures that the amount of
time spent acquiring data is optimized and that the data being displayed is
valid for the current settings.
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