Jags randomly stop working?

We’ve run into an issue where we would be running around all fine, then randomly one of our drive wheels stops completely responding. A full power cycle of robot brings it back online but why is it going into shut down? On the dashboard I would get a response from jag timeout error sometimes but the robot is still fully functional when I get this error. Also we are running a CIM with a 12:1 banebot transmission and 8" wheel. Monitoring the current(through CAN interface) it only averages about 20 amps with peaks up to 40-50. Previously we had a 4:1 transmission and it averaged 40 amps with 80 amp peaks and there seemed to have been an issue of tripping breakers and that would also make the jag stop responding. But with this new setup we arn’t drawing that much current. These are brand new JAGs direct from VEX so there’s no crap inside of them.

We have decided we can’t afford to risk losing a wheel during competiton so we have removed the jags from drive functions and replaced them with Victor 888s.

This is truly a disappointment I had such high hopes for these things.

I have tried swapping jags around and replacing all of them and this issue still arises. It’s predominantly one wheel that always goes out but the other ones sometimes do it too.


In the past (2010, 2011) we had some pretty significant errors using CAN with the Jaguars. If the connectors came loose at all they would shut down. Sometimes waiting 45-60 seconds would bring them back, sometimes it would take power cycling the robot. As a result we don’t use CAN any more (even though it has many features we would like). I do know a couple of mentors whose teams use CAN successfully. They use tape and/or zip ties to secure the connections so that the cables cannot be jarred loose.