Manual Operation - C204A3 Error and Ramdom C153A1


We have a UR10 robot and it worked fine for 3 years with the same program. But now, when we have a complex movement with the shoulder and elbow combined, it fails when the elbow is extended. At this point, it shows error C204A3.

We can check the repetition of this failure in any position of the shoulder and only when the elbow is aligned or fully extended (attached image). This fault occurs when you move your shoulder and elbow together (manually or with a program). But if we move each axis independently or alone, it does not fail.

Added to this, sometimes the shoulder fails and gets stuck, showing error C153A1.

We already checked power supply, wiring, encoders (they don’t look bad) and motors (they don’t look bad either). How can we fix this error? Or what should we do to repair it?


That looks like singularity.

Yes, it is true, but that would be correct if we analyze it from the control approach through a specific program which may have interpretation errors or sign changes in the axes.

The problem is that this error does it using the manual commands indicated in the attached figure.

I mean you can still manually jog the robot into singularity, so I’m not exactly surprised that the error pops up.

Likely the “sudden stop” that’s throwing the fault is due to entering singularity.

Yes, we know about this problem and know about this singularity.

The problem we have is that this happens after 3 years of being working without having had any problem, so we have to assume that it is a failure or damage to the robot. But we don’t know how to proceed, since it behaves equal to this singularity.

I would contact your vendor/distributor, or submit a ticket with myUR. You can send the log file and they can pull information on it to determine if a joint is going bad, or a bad encoder, or whatever.