Corrected from:
- i700 servo inverter V01.07.05.10577
Response of the new version:
As a matter of principle, it is not possible to avoid a certain time offset between the actual values detected and the corresponding setpoints. The time offset can at best be reduced to a theoretically smallest possible value.
The timing behaviour of the tasks in the i700 servo inverter has now been optimised. Now, the time offset of actual position and actual speed corresponds to the theoretically smallest value:
New: Toffset = (2* Tbus cycle) - 250µs
What happens?
Due to the task and timing framework used in the i700, the actual values are not determined by means of the values from the last cycle, but by means of the values from the last but one cycle.
This is why the actual values transmitted via PDO to the higher-level control system are 250µs older than optimally possible.
As a result, the resulting time offset between setpoints and actual values has been:
So far: Toffset = (2* Tbus cycle)
When does this behaviour occur?
Permanently.
Which products are affected?
- i700 servo inverter
Short-term measures:
None.
Evaluation/recommendations:
How does the optimised timing described affect applications:
Position control within the controller (major part):
- No significant effects have to be expected.
Position- and/or speed-control loop within the higher-level control system (if required for applicative reasons):
- The control characteristics will be basically better than before because the reduced time offset in the actual value detection has a positive effect on the stability of the control loop.
- In existing applications, the optimised timing may lead to a slightly different drive behaviour. In this case, better results will be achieved.
