What happens? When changing the CiA operating mode, an unexpected rise occurs in the following error characteristic.
When does the problem occur?
The rise in the following error characteristic occurs at the time the CiA operating mode (0x6060) is changed, e.g. when changing from cst to csp.
When changing the operating mode, the source of the speed setpoint changes as well (in the example from 0x2946 to 0x60B1). For a jerk-free changeover, the new speed setpoint must become effective immediately. Only in that case the setpoints for speed and position will be consistent.
The unexpected rise of the following error is due to the influence of the interpolation function existing in every signal path. So far, this has led to a ramp-wise speed setpoint characteristic if old and new setpoint are different. In particular, when changing over from cst to csp, the setpoints typically deviate extremely from each other:
With the torque mode (cst), the speed controller is used for speed limitation. In this case, the setpoint speed serves as speed threshold for the limitation and is set to correspondingly high values.
With the position mode (csp), the speed controller is acutally used as a speed controller. When changing the operating mode at standstill, the setpoint speed is zero here.
Which products are affected?
- i700 servo inverter ≤ V01.06.03.9953
Short-term measures/recommendations:
As an applicative solution, adapt the speed setpoints (new and old) before changing the operating mode.
When changing over from cst to csp, you can set the limit values for speed limitation to zero (0x2946:1 and 0x2946:2) one cycle before changing the operating mode (assumption: changeover at standstill) and set them to their previous value after changing the operating mode.
Evaluation:
On request, there is an applicative solution available as a remedy.
