niswitch very slow with signal connected (PXI-2535)

[morngoose]

First time using a FET switch card, running basic vi where I connect a row and two columns and do a resistance measurement with a DMM.

I found that with the DMM connected, ie signal applied, the switch can take more than 5 seconds to close. (DMM ohm reading 26 ohms after 5 seconds, although the 'wait for debounce' vi reported all good)

If the DMM is not connected, it happens instantaniously.(disconnect DMM, perform switch action, connect DMM - instant closing)

Anyone experienced the same ?

[morngoose · Accepted solution]

Found the problem.

Seems the FET card goes into protection mode if you dont connect the DMM - signal to chassis GND.

After doing that, it worked fine.