Siemens SINAMICS S120 - Page 601

Function modules
8.14 Advanced Position Control (including Active Vibration Suppression)
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
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It only makes sense to measure the closed APC circuit if a direct measuring system is being
used. See also the examples in Chapter "APC with acceleration feedback (Page 609)".
The effect of the functions on the frequency response is very similar in both cases.
Red:
APC inactive: The closed-loop control is at the limit of its stability. The position control gain is too high.
Yellow: APC active, p3761 = 3 ms: The oscillation is dampened. The position control gain can be kept - or even in-
creased slightly.
Figure 8-34 Reference frequency response, position controller, control on a direct measuring system
If a direct measuring system exists, then the APC can be set well by measuring the
reference frequency response of the position controller. In the example the damping effect
as a result of APC can be seen for an oscillation frequency of 22 Hz.