Sweep a Keithley 2440 - initial ok but error on restart +803

[clonsway]

I have a vi to sweep a keithley 2440 (GPIB comm with an HP 82357B usb to GPIB)).  It works fine repeatably on start up.   When I shutdown labview and then restart the vi to run - the Keithley errors - +803 - not permitted with output off.  Then the instrument does not respond to any communication.  If I then power off/on the Keithley, with my vi still open - the vi works fine and communication is restored.  Obviously this is not desirable.

[cymrieg]

Could be any number of things causing this. Run NI-Spy first and monitor what gets sent to the instrument when you shutdown the vi and then restart it. The error is indicating that a command is being received like "read data" when the source output if off.

I wouldn't suspect the USB to GPIB convertor yet.