Universal Robots Forum

C4A1 error when jogging manually on UR10 CB3.0 above 3.11


Since upgrading both our UR10 CB3.0 to 3.12 and up till 3.14 we have had constant C4A1 errors while jogging the bots manually. They run flawlessly for days when running programs, but when stopped and moving manually or moving to a waypoint with the automove tab, the bots will consistently throw a C4A1 error after some minutes. Same issue on 2 different robots.

This makes it very impractical or impossible to use with sensitive payloads as we risk crashing expensive tooling while calibrating or programming moves while close to static objects and surfaces.

The only workaround has been to downgrade to 3.11 where the issue has disappeared completely. We obviously would prefer to be on 3.12 and above due to the safety alert fixes.

Please contact your distributor/integrator for a better investigation of this issue.

Hi, I am already in touch with our local distributor. I thought it would be useful to post here in case others are seeing the same behavior and might have found solutions. We initially thought that the common behavior seen on both robots could be an electrical noise issue, but this was also observed on other locations with the same robots, and totally disappeared since going back to 3.11.

I will report back here once we have found a solution.

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Hi! Did you end up finding a solution? I think Iā€™m having the same issue on 3.12.


Unfortunately not yet. Only solution was downgrading to 3.11 which completely eliminated the problem. I really hope we figure this out so we can upgrade again to 3.14.x and above. I will post here if we find any solution, but for now our 2 UR10 are on 3.11 and working fine.

Btw, if you also downgrade to 3.11 and it also eliminate the issue please report here as that would be an independent confirmation that this is indeed an issue not locally isolated to us, thanks.

I just downgraded and it fixed it for me as well. Before this I was getting the C4A1 error every few minutes.

Interesting. Is it also a CB3.0 controller? UR10? Are you in touch with UR directly? might be good to raise the issue with them directly, good to know we are not alone!

Can you run programs ok? we only see the issue when jogging manually, running programs is fine.