XR Expansion SPDT 32-Relay Controller not responding


I am using an “ProXR Industrial Relay Controller Board 32-Channel SPDT + UXP Expansion Port” with a quantity of 3 “XR Expansion SPDT 32-Relay Controllers”. I am also using the RS-485 Serial Communications Module.

I have an issue where the last expansion board in my chain isn’t responding to any commands. All others are working fine. I am also using the 6″ XR Expansion Cable that is provided on every unit.

Any ideas on what could be the issue here?


Hi Dane,

Sometimes it’s possible for one of the driver chips on the board to become damaged. Try rearranging the boards in the chain to see if the issue is still with the same bank of relays, also check to see if relays after that bank still function.

Let me know what you find.

Thank you,
Travis Elliott

I did a few tests rearranging the order of the boards.
Looks like the expansion out port of the previous board is not working.
I can just move this one to the end of the chain and everything should work out for me.



I am having a similar issue;
I have a gen3 eth-ser controller board and 4 XR245 expansion boards.
Only the 3 banks on the controller board are working.
Tried with each of the expansion alone, then chained.
Never could get the expansion relays to flip.
Tested with different xr cables, and isolated 12.3v power supply.

Is there a pinout for the XR port that I can use to check for any serial data coming out at all?
Could it be the bank 3 shift reg chip is bad on controller board?

Skyler C.