Siemens SINAMICS G120 Operating Instructions Manual page 304

Advanced commissioning
6.21 Motor control
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. Set p0340 = 4. The inverter again calculates the speed controller parameters.
9. Switch on the motor.
10.Over the complete speed range check as to whether the speed control operates
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:
● Encoderless vector control - and vector control with encoder
– Increase p1452 (smoothing the speed actual value).
– Increase p1472 (integral time T
– If, after these measures, the speed controller does not operate with an adequate
● Additional settings for vector control with encoder
– Increase p1441 (smoothing the speed actual value): p1441 = 2 ... 4 ms.
302
dynamic performance, then increase p1470 (gain K
Initially, the speed actual value follows the speed setpoint with
some delay, and then overshoots the speed setpoint.
● Increase p0342
Initially, the speed actual value increases faster than the speed
setpoint. The setpoint passes the actual value before reaching its
final value. Finally, the actual value approaches the setpoint with‐
out any overshoot.
● Reduce p0342
): T ≥ 4 · p1452
I I
Operating Instructions, 04/2018, FW V4.7 SP10, A5E31759476B AG
) step-by-step.
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Converter with the CU250S-2 Control Units