The overcurrent ("OC") error occurs when an axis draws more current than its maximum set value.

This error generally only occurs on our closed loop BLDC axes, which draw as much current as needed by the requested motion (i.e. if you try to move faster or increase the axis' load it will need more current to follow the target position). If an axis tries to move faster than possible but does not reach its maximum current a position lag error may occur instead.

Our open loop stepper controllers always draw the maximum set current for the motion situation (moving, idling, referencing,...), if they get overloaded an encoder error may occur indicating position lag.

If the error occurs when starting the motion or trying to move slowly the axis may be blocked or defective.

Troubleshooting

Axis does not move at all or only slightly

Symptoms (Overcurrent error occurs when):

when enabling the axes
when starting to move
when trying to move slowly

Check the following:

Check whether the axis is blocked by some obstacle
For linear rails without brake: Check whether the axis is easy to move when not powered (turn off the control cabinet or enable Zero Torque Mode)
For motors with a brake: Check whether the brake is released
- The LED at the brake relay should be lit
- Check whether voltage is applied to the brake
For igus ReBeL arms
- Do a firmware and parameter update
- If this does not help contact support, there may be a defect

Axis is able to move

If the axis is able to move further than just a few degrees or mm but fails during faster motion it likely is overloaded. Check the following:

Check whether the axis is blocked by some obstacle
For linear rails without brake:
- Check whether the axis is easy to move when not powered (turn off the control cabinet or enable Zero Torque Mode)
- Check whether the linear rails are properly aligned
Check whether the robot moves reliably without load at the tool (or without tool if it is heavy).
- Try lowering the weight
- Try decreasing the speed of the failing motion command
- Consider increasing the current limit if nothing else helps

In some cases an overloaded axis can be fixed by increasing the current limit. However, this is discouraged and should only be the last resort since it can damage components if not done carefully. The current of igus ReBeL axes should generally not be increased past the standard value.