Solution
The PXI-2520 is probably overloaded and getting welded closed. Many power supplies have a lot of capacitance or inductance on their output. These cause a lot of arcing, which leads to relay damage when hot switching.
Although the device handles 150V and 2A, the maximum switching power is limited to 60W. This means the device could not switch both max voltage and max current at the same time. Setting the switching voltage to 100V and the switching current to 800mV will be 80W switching power.
Below is some suggestion to use the PXI Relay Module correctly.
-
Reduce the switching voltage and current provided to the relay so that it would not exceed the maximum switching power of 60W.
-
Set the switching voltage to zero, as giving switching voltage during toggling will cause current spikes. This will eventually shorten the relay lifetime.
Note: NI PXI relay modules in fact do not require any voltage or current to be flowing through theirs relays in order for them to properly switch.
-
Put some high power resistors in series with the power supply to reduce the switching current.
If you are suspecting the PXI Relay Module is damaged, you may try the below troubleshooting steps to confirm:
- Make sure the switching voltage, current, and power do not exceed their own limitations and perform the relay switching using NI Switch Executive to check whether the module is working properly.
- Change the PXI relay channel and retest the switching function.
- Change the PXI Relay Module to isolate if the issue lies on hardware or software.
- Perform self-reset and self-calibration in NI MAX to confirm if the tests are passed.
- Reset NI MAX database.
If you confirm the PXI Relay Module can no longer control the basic functionality of the relay, please proceed for RMA by asking for help at ni.com/ask.