Calling OpenDev from within IVI device driver

[pblase]

I need to perform a GPIB serial poll from within an IVI device driver (I'm writing in LabWindows/CVI) in order to figure out which one of several possible instruments set the SRQ line. VISA doesn't have a serial poll command, so I have to use the raw GPIB functions from the Library/GPIB menu. The GPIB serial poll command wants the device handle from OpenDev(); OpenDev wants a device descriptor. How do I get the device descriptor from IVI? It's got to be in there somewhere, but I can't find an attribute that carrys it or a function that returns it. I think that I successfully installed the GPIB SRQ handler, at least it seems to work ok.

Paul

[Makoto]

> VISA doesn't have a serial poll command,

VISA does have the serial poll function -- viReadSTB().

> How do I get the device descriptor from IVI?

The NI-488.2 device (or unit) descriptor is isolated from VISA, so there is no way to acquire from your app through the VISA API.

[pblase]

Ah, thanks. I was looking for it to be along with the rest of the GPIB functions.

Paul