User`s guide

218 34980A User’s Guide
8 Microwave Switch/Attenuator Driver
Long Execution Times
When configuring long channel pulse drive times and/or power supply
recovery times, be aware that the results may be long execution times in
the mainframe. For example, you can set a channel pulse width of 255 ms
and a recovery time of 255 ms. This channel will require 510 ms to open
or close. If you set such parameters across all the channels on a remote
module then the execution time will be over 30 seconds. The mainframe
will display the message
LONG OPERATION SLOT n BUSY on the display
when this is happening.
Be aware, all channel states are driven when the remote module is reset.
So, this lengthy execution can occur following a power on,
*RST,
SYSTem:CPON, SYSTem:PRESet, or ROUTe:RMODule:DRIVe:SOURce command.
Verifying Switch State
Many switches and attenuators have a built- in switch position indicator.
This indicator can be used to drive LED position indicators (some position
indicator circuits are shown beginning on page 254). Additionally, the
34945A checks the position indicators against the SCPI command last sent
to provide verification of switch states.
By default, verification is disabled and the switch state is assumed to be
the last open/close state driven. Verification is enabled using the
ROUTe:CHANnel:VERify:ENABle command. Enabling verification can cause
multiple errors to be generated if the system is incorrectly configured.
If a switch operation appears to have failed, an error is generated at the
time the
ROUTe:CLOSe or ROUTe:OPEN command is executed. If you send a
ROUTe:CLOSe or ROUTe:OPEN command with a channel list (i.e., multiple
channels), the verification is performed after all open/close operations
have been completed. An error is generated for each channel operation
that did not properly verify.
The verification process will affect the operation of the
ROUTe:CLOSe? and
ROUTe:OPEN? commands. If verification is enabled, these commands will
check the actual hardware state of the specified channels, rather than just
reporting the presumed state.
When verification is enabled and a remote module is reset, a series of
errors will be consolidated and reported as one error.
Verification will slow switching performance on any remote module with
one or more verified channels. Additionally, if you have enabled the
command overlap function (using the
ROUTe:OPERation:OVERlap:ENABle
command), the verification will be performed at the end of each
close/open operation, before processing the next command.