Procedure
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):
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
nal value. Finally, the actual value approaches the setpoint with‐
out any overshoot.
• Reduce p0342
7. Switch o the motor.
8. Set p0340 = 4. The converter 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
(p1120and p1121) back to the value before optimization.
Mastering critical applications
The speed 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 p1452 (smoothing the speed actual value).
• Increase p1472 (integral time T
I
): T
I
≥ 4 · p1452
• If, after these measures, the speed controller does not operate with an adequate dynamic
performance, then increase p1470 (gain K
P
) step-by-step.
Advanced commissioning
7.20Motor control
SINAMICS G115D Wall Mounted distributed drive
292 Operating Instructions, 07/2023, FW V4.7 SP14, A5E52808211A AA
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