NI Switch Relay Position Confirmation Technique

Updated May 15, 2019

Reported In


  • PXI-2530B



Issue Details

How does the PXI-2530B switch block detect the switch was successful in the multiplexer's connection?


The PXI-2530B does not have a built-in method to confirm the channel connection was successful. Nevertheless, National Instruments (NI) runs every switch module through extensive continuity tests before leaving manufacturing and is confident of the switches expected lifetime, assuming the device is operated within its specifications.

NI Switch Health Center

NI Switch Health Center is a feature compatible with NI's recent and future switch modules and helps determine the current health of the switch relays. While this feature is not available with the PXI-2530B, this feature is available with some of NI's newer SwitchBlock modules

Switch Relay Life

The Reed Relay Lifetime Nomograph is available in most NI Switch specification sheets. Comparing the Relay Count on the eeprom with the expected timeline in the device's nomograph is helpful in building confidence that the switch module is behaving appropriately.

Recommended Switch Relay Connection Confirmation 

Finally NI's standard recommendation is to implement code in such a way that the channels containing potentially dangerous voltages and currents are intentionally checked at various points along the test. This will help ensure dangerous voltages and currents are drained appropriately before continuing with the switch test.