Hi jbebko,
Thanks for your question! Unfortunately, there is not a software method of detecting relay failure on your cards through NI-SWITCH or NI-Switch Executive. In order to detect relay failures we have to send a digital signal through every relay on the module and detect if it is working or not. This extra circuitry is not present on any modules other than NI SwitchBlock as well as the NI PXIe-2737, 2738, 2739, 2524, 2525, & 2526 via the Switch Health Center. It is also important to realize this Switch Health Center testing can only be done when signals are disconnected (because we do not want to send voltage into a DUT, or read a DUT's signal instead of our desired digital signal), so even with NI SwitchBlock it is not a programmatic function that can be called during testing.
Below is the link to the description of NI Switch Health Center just to give some background in case that might be something that would interest you:
http://www.ni.com/white-paper/11971/en/
Cheers,
Hannah
National Instruments
