Agilent Technologies L4400 manual Long Execution Times, Verifying Switch State

Microwave Switch/Attenuator Driver 7

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. 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.

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 184). Additionally, the L4445A 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.

The state of all verified channels on a remote module is refreshed whenever any channel on that remote module is operated. This helps to ensure the front panel and web based interface have a valid state.

L4400 User’s Guide 149