Simulink Control Design™ - MathWorks

(^4) Depending on the quality and features of your response data, you might want to
perform some preprocessing on the data to improve the estimated plant results. The
Preprocess menu gives you several options for preprocessing response data, such as
removing offsets, filtering, or extracting on a subset of the data. In particular, when
the response data has an offset, it is important for good identification results to
remove the offset.
In the Plant Identification tab, click Preprocess and select the preprocessing
option you want to use. A tab opens with a figure that displays the original and
preprocessed data. Use the options in the tab to specify preprocessing parameters.
7 PID Controller Tuning