Is this possible?

[DeMoNA]

Hello. 

I have a PXI-4070 mux'd with a PXI-2503. I am trying to create multiple VI's to read the DMM (for example, one VI for voltages on a range of channels, one for resisrtance on another range, etc). Is this possible? There appears to be only one IVI instrument handle for each PXI device and whenever a new VI is run it wipes out the VI that was already running.

Thanks.

[crossrulz]

The DMM can only be doing 1 thing at a time. If you want it to do multiple things, then you need an application/VI that your other applications/VIs can talk with. That lone VI does all of the interfacing with the DMM, acting as a mutex as needed.

[jerrymarlowe45]

Hello,

You can absolutely read different measurements from your PXI-4070, but since IVI drivers only allow one session per instrument, the best approach is to use a single shared handle or a master VI to  manage all measurements.

[TobiasG]

This page may be helpful: https://www.ni.com/docs/en-US/bundle/ni-dmm/page/programming-flow.html

When you call niDMM Initialize [With Options].vi, it reserves the instrument's resources as represented by the session wire. This session wire should be passed into all further calls on the instrument until you are ready to release the instrument's resource, at which point you call niDMM Close.vi.

The NI-DMM examples should be instructive here, although few if any use nested subVIs, being programming usage examples.