You always have to run the network analyzer application to get
the LCA functionality. Therefore if you only run the network
analyzer and NOT the LCA SCPI interface, the USB device port
is taken by the network analyzer SCPI talker/listener. When
you first connect your PC with a USB cable to the LCA
(combined instrument), you get the Network Analyzer
identification string if you send the *IDN? query.
If you start the LCA SCPI interface and configure it to run on
the USB device port, you will get theidentification string for
the LCA instrument when
you send the *IDN? SCPI query.
However, if you run the LCA SCPI interface on the socket port
and have connected your PC via USB with the LCA instrument,
the network analyzer
identification string will still be returned.
After a system reboot, the USB device port is always taken by
the network analyzer SCPI interface by default. The LCA SCPI
interface has to be started manually. If you run the LCA SCPI
interface on the USB device port and want to switch to the
socket port, you have to stop the LCA SCPI interface first, then
change the configuration to socket port and save it. This action
will restart the network analyzer application automatically, to
reclaim the USB device port for the network analyzer. Now the
LCA SCPI interface can be restarted with the new
configuration.
GPIB port
The LCA SCPI interface doesn’t support the GPIB port.
However you may control the network analyzer application
through SCPI over the GPIB port.
This gives you the possibility to control the instrument
independent of LAN by controlling the LCA application
through SCPI over USB and the
network analyzer application through SCPI over GPIB.
Remote Operation
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Keysight N437x Series Lightwave Component Analyzer, Programmer’s Guide