Unknown package command error

Technical Questions Robot Communication
1

I am using the RTDE python client to communicate with our UR3e in a machine tending application. Intermittently I receive an “unknown package command” (logged to stderr). I believe this is due to a corrupted packet received across a potentially communication link (point-to-point ethernet cable in our case). Currently this error locks our client application and I need to shut it down and restart. I’d like to catch the error (as an RTDEException?) and gracefully recover from the error by essentially ignoring it and continuing with our synchronization loop.

I traced the error to the __on_packet function which is an internal method in the RTDE class object. The error arose during a call to the receive method. When the error condition arises, a message is logged but there does not appear to be any exception thrown: __on_packet returns “None” and I couldn’t find any downstream code that would check for this. I’d like to be able to catch this error as an exception and gracefully recover - essentially ignoring it and continuing with our synchronization loop.

Is there an exception that does get thrown by the receive() in response to this error that I could catch?

Thanks,

Chet

2

Have you resolved this problem or found any solution?

We are experiencing the same problem, but it occurs very rarely for us. We also need to restart the app when it happens.

3

We never resolved it, but as with your case, it rarely occurs.