Instrument Control (GPIB, Serial, VISA, IVI)

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Does CloseDev issue GTL ?

I am using the CVI GPIB library and the CloseDev command.  Does CloseDev issue a go-to-local 488.1 command to the device being closed?

If I issue a go-to-local (GTL) command prior to the CloseDev command, I get a -1 returned value from CloseDev.

The CloseDev help says it takes the device "off line".  What does that mean?

Thanks.
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Using NI-Spy, you can confirm that it does called ibloc(), which, if you look in the NI-488.2 help, places the device in local mode.  So, yes, it's sending a GTL when you call CloseDev.  Taking the device offline usually just means closing out the handle to it in the driver (and not doing anything to the device itself).  CloseDev sends GTL as well.

Scott B.
GPIB Software
National Instruments

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