Siemens SINAMICS G120C Operating Instructions Manual page 208

Advanced commissioning
6.5 Motor control
Procedure
To optimize the speed controller, proceed as follows:
1. Switch on the motor.
2. Enter a speed setpoint of approximately 40 % of the rated speed.
3. Wait until the actual speed has stabilized.
4. Increase the setpoint up to a maximum of 60 % of the rated speed.
5. Monitor the associated characteristic of the setpoint and actual speed.
6. Optimize the controller by adapting the ratio of the moments of inertia of the load and
motor (p0342):
7. Switch off the motor.
8. Start a new calculation of the speed controller: p0340 = 4.
9. Switch on the motor.
10.Over the complete speed range check whether the speed control responds satisfactorily
with the optimized settings.
You have optimized the speed controller.
When necessary, set the ramp-up and ramp-down times of the ramp-function generator
(p1120 and p1121) back to the value before optimization.
Mastering critical applications
The drive control can become unstable for drives with a high load moment of inertia and
gearbox backlash or a coupling between the motor and load that can possibly oscillate. In
this case, we recommend the following settings:
● Increase the smoothing of speed actual value p1452.
● Increase the integral time: T
● If the closed-loop speed control no longer has an adequate dynamic performance after
these measures, then increase the P gain K
204
Initially, the actual speed follows the setpoint speed; however, it
then overshoots the setpoint speed.
Increase p0342
•
Initially, the actual speed exceeds the setpoint speed; however,
it does not overshoot but instead approaches the setpoint speed
"from below".
Reduce p0342
•
≥ 4 × p1452.
I
step-by-step.
P
Operating Instructions, 07/2015, FW V4.7 SP3, A5E34263257B AC
SINAMICS G120C converter