So I have an odd issue. I am useing the IVI scope driver to control my scope over GPIB. My routine initializes the scope and then loops waiting for what to do. The first time I call the subvi to setup for a capture it works great. Sets all the aquasition info like trigger level, channel, type.. all that stuff. Subsequent calls don't do anything though. No error codes, just does nothing. The initiate command does continue to work. I just cannot change any of the aquasition settings like trigger level or channel or anything. Please help.

OK, found the "problem". The driver is too smart. If you command it to say trigger on CH1, it remembers this. So if later you ask it to trigger on CH1 again it doesn't actually set the scope; it assumes it is still set to CH1. Not good it someone manually changed this setting in the interm. There is a function to invalidate all parameters that fixes this. If you call this first, it clears the history and it will always try to set the parameters. Perhaps I am paranoid, but I do not trust that someone will not hit something mid-test.

Instrument Control (GPIB, Serial, VISA, IVI)

ivi scope only sets aquasition first time

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Mis-read your post. Makes sense now. Thanks.

@Dennis_Knutson wrote:
That is exactly what i told you about the state caching feature of IVI. Instruments can be behind a locked door. Operators can be punished for touching an instrument.

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Instrument Control (GPIB, Serial, VISA, IVI)

ivi scope only sets aquasition first time

Re: ivi scope only sets aquasition first time