For a more detailed example of a Simulink model configured for open-loop PID
autotuning, see “Tune PID Controller in Real Time Using Open-Loop PID Autotuner
Block” on page 8-31.
Step 2. Configure Start/Stop Signal
To start and stop the autotuning process, use a signal at the start/stop port. When the
experiment is not running, the block passes signals unchanged from u to u+Δu. In this
state, the block has no impact on plant or controller behavior.
The frequency-response estimation experiment begins and ends when the block receives
a rising or falling signal at the start/stop port, respectively. In the systems illustrated
in “Step 1. Incorporate Autotuner into Model” on page 8-9, the start/stop signal is a
simple switch. While the model is running, you can use the switch to begin and end the
experiment. When you end the experiment, the algorithm generates the tuned PID gains
and the block returns them at the pid gains port.
As an alternative to a manual switch, you can configure the start/stop signal to begin
and end the experiment automatically at particular simulation times. For example, you
can use the sum of two Step blocks: Configure one Step block to step from 0 to 1 at the
PID Autotuning for a Plant Modeled in Simulink