Siemens SINAMICS S120 Function Manual page 119

● Do not change the Kp (speed controller gain).
● Activate the torque precontrol.
Automatic pre-assignment
When the "Online tuning" function is activated, settings are made that ensure the safe operation
of the online tuning.
Current setpoint filter
The natural frequency of the first PT2 filter behaves proportional to the current controller and
speed controller cycles. The faster the sampling, the higher the positive feedback frequency
and therefore the higher the frequency must be set for the current setpoint filter.
A lower dynamic response via p5272 makes the control loop less sensitive to resonance from
the drive train.
A higher dynamic response via p5272 makes the control loop more sensitive to resonance from
the drive train.
The instability of the control loop through resonance can also be avoided through the
parameterization of additional band-stop filters in the current setpoint.
Speed actual value filter
An actual speed value filter is required, for example, when the resolution of the encoder is
relatively poor. Depending on the encoder resolution and the motor moment of inertia, an actual
speed value filter (p1441) is calculated. The time constant of the actual speed value filter is
taken into account in the calculation of the controller parameters.
Adaptive resonance filter
The limit frequencies for the adaptive resonance filter are pre-assigned according to the set
sampling time. These can be changed manually.
Additional settings and displays
● Set the dynamic response factor (p5272) for the entire P gain of the speed controller.
● Set the estimated load moment of inertia component for the P gain of the speed controller
with the load dynamic response factor (p5273).
● Display the estimated dynamic response (r5274) of the speed control loop as PT1 time
constant.
● Set the same time constants for the dynamic response time constant (p5275) so that the
interpolating drives receive a defined dynamic response via the precontrol. However, this
does not always ensure positioning without overshoot.
● The estimated Kv factor is displayed (r5276). This value can be used for a higher-level
control system, to set the position controller gain. Precondition: DSC is active in the drive.
● The estimated precontrol symmetrizing time is displayed (r5277). This value can be used for
a higher-level control system, to symmetrize the position controller precontrol. Precondition:
DSC is active in the drive.
Drive functions
Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Servo control
5.9 Autotuning
117