The control error is a user defined software protection.

ERRMAX parameter represents the maximum accepted control error of the most outer loop of the controlled system (i.e. speed or position). If the difference (POSERR/SPDERR) between the reference (TPOS/TSPD) and the feedback (APOS/ASPD) exceeds this value for a time that is greater than the value specified by the TERRMAX parameter, then the controller error protection is triggered. By default the power stage of the drive is disabled and the user intervention is required.

The control error protection determines if:
– the feedback is completely lost (i.e. encoder wires disconnected or just loosen)
– the load is just too big and the motor (APOS) can’t keep up with the reference (TPOS) and the system is no longer in the desired precision range

If the control error protection is triggered but non of the above cases is present then it was caused, in most of the cases, by:
– the parameters for this protection are set to wrong values, so that the protection is triggered in fact in a false manner, on a situation which is not a real control error issue
– the tuning of the system – it might not be good enough to maintain the user imposed precision
– the number of encoder lines is not properly defined
– the load is too high and thus the motor can’t move enough during pole lock sequence (phase alignment)
– the encoder is not placed directly on the motor shaft and there’s a backlash between them causing a misalignment between the rotor and the magnetic field, followed by torque looses. If this is the case you’ll have to move the encoder on the motor shaft.
– the encoder pulses are subjected to spikes and therefore the drive is loosing encoder pulses.

To avoid this situation:
– shield and route separately the encoder and motor cables (if not already done)
– put a small capacitor (10uF@ 6.3V) on the encoder (between GND and +5V).