Main Content

Input/Output Data for Identification

Data Preparation

Identification of a plant model for PID tuning requires a single-input, single-output data set.

If you have measured data, use the data import dialogs to bring in identification data. Some common sources of identification data are transient tests such as bump test and impact test. For such data, PID Tuner provides dedicated dialogs that require you to specify data for only the output signal while characterizing the input by its shape. For an example, see Interactively Estimate Plant from Measured or Simulated Response Data.

If you want to obtain input/output data by simulating a Simulink® model, the PID Tuner interface lets you specify the shape of the input stimulus used to generate the response. For an example, see the Simulink Control Design™ example “Design a PID Controller Using Simulated I/O Data.”

Data Preprocessing

PID Tuner lets you preprocess your imported or simulated data. PID Tuner provides various options for detrending, scaling, and filtering the data.

It is strongly recommended to remove any equilibrium-related signal offsets from the input and output signals before proceeding with estimation. You can also filter the data to focus the signal contents to the frequency band of interest.

Some data processing actions can alter the nature of the data, which can result in transient data (step, impulse or wide pulse responses) to be treated as arbitrary input/output data. When that happens the identification plot does not show markers for adjusting the model time constants and damping coefficient.

For an example that includes a data-preprocessing step, see: Interactively Estimate Plant from Measured or Simulated Response Data.

For further information about data-preprocessing options, see Preprocess Data.