Implementing Autotuning with the Autotuning Wizard

To use the Autotuning Wizard to improve your controller performance, you must first create your control application and determine PID parameters that produce stable control of the system. You can develop the control application using either the PID VI, the PID Gain Schedule VI, or the PID Autotuning VI. Because the PID Autotuning VI has inputs and outputs consistent with the other PID VIs, you can replace many PID VIs with it.

Note��The PID Autotuning VI cannot directly replace the PID Advanced VI or the more advanced autotuning VIs, such as PID Advanced Autotuning or PID Online Autotuning. These VIs provide advanced functionality that the PID Autotuning VI does not support.

Autotuning-Specific Inputs

The PID Autotuning VI has several inputs and outputs specific to the autotuning procedure, including the following inputs:

• autotuning parameters�A cluster of parameters that the PID Autotuning VI uses for the autotuning process. The Autotuning Wizard allows you to specify all of these parameters manually, so wiring this input is optional.
• autotune?�Specifies whether to invoke the Autotuning Wizard and begin autotuning. Wire a Boolean control, such as a button, to this input so a user can press the button to open the Autotuning Wizard. The Autotuning Wizard steps the user through the autotuning process.

  Note��Set the Boolean control mechanical action to Latch When Released so the Autotuning Wizard does not open repeatedly when the user presses the button.

Autotuning-Specific Outputs

The following outputs are specific to the autotuning procedure:

• tuning completed?�Indicates when the autotuning process is complete. You can use this output to determine when to update the PID gains values.
• PID gains out�Returns the tuned PID gains. Before autotuning completes, PID gains out returns the same values as the PID gains input. PID gains out updates only when autotuning completes and tuning completed? returns TRUE.