Expansion Hub Randomly Stops Responding

Our expansion hub has been giving us this error for the whole season and we have replaced it multiple times. Sometimes our motors plugged into it will just go haywire.
Below are our log files from today:
Log Files

Do you have 2 RS485 wires plugged in between the Control Hub and the Expansion Hub? It provides redundancy and may help with your intermittent issue.

I agree with @jvanier, the 3-wire data cable is the usual suspect for this kind of failure, if there is an intermittent short in the cable you get this exact scenario. I would replace the 3-wire data cable between the Control and Expansion hubs, and even add a second one as a redundancy - the two RS485 data ports on the hubs are redundant, so you can add a second cable that will be used in case either stop communicating. That doesn’t mean a command might not get garbled if one cable goes bad mid-match, but you won’t lose communications and the system will recover quickly.


Is this redundancy in the RS485 pathways documented? It’s not clear if the dual pathway would cause any signal integrity issues? I know the RS485 is a continuous bus pathway, but with the potential in slight differences in length causing an issue with signal I’m not sure if doubling up on the wires is proper.