Siemens SINAMICS S120, Function Manual

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Function modules
8.14 Advanced Position Control (including Active Vibration Suppression)
Drive functions
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Function Manual, 11/2017, 6SL3097-4AB00-0BP5
8.14.8 Measuring frequency responses
This chapter describes which measuring functions are available to measure the relevant
frequency responses, and how these can be executed.
Are you As APC has its own control loop, it is always recommended, when starting
optimization, to measure the open circuit once with a high bandwidth (e.g. 4000 Hz for a
speed controller clock cycle of 125 µs). This measurement can be used as basis to derive
whether and which filtering is required to stabilize the control loop. This is especially
important for APC using a direct measuring system.
However, to optimize APC further it is better to perform the measurements with a lower
bandwidth (e.g. 400 Hz - the lower the oscillation frequency, the lower the measurement
bandwidth), as the frequency resolution of the measurement increases.
Use case SINUMERIK
There are several predefined measurement functions in HMI Operate to measure APC
control loops. Measurement functions "APC open circuit" and "APC closed circuit" are
available in the menu "Commissioning > Optimization/test > Speed control loop".
Note
These measurement functions are only displayed if a value > 0 is entered in the parameter
p3761! When activated for the first time, APC should still be inactive (p3700.0 = 0).
The encoder combination function can be measured using predefined measurement
functions "Speed-controlled system", "Open speed control loop" or "Speed controller
reference frequency response". The differential position feedback function can be measured
using "Open speed control loop" or "Speed controller reference frequency response".
All APC functions can be measured at the reference frequency response of the position
control loop (in menu "Commissioning > Optimization/test > Position control loop" select
measurement "Position controller reference frequency response").