Simulink Control Design™ - MathWorks

Here, the blocks marked Read plant output from hardware and Write plant

input to hardware represent hardware interfaces that read data from or write data to

your physical plant. When you are ready for tuning, you run this model in external

simulation mode.

Bumpless Transfer for Open-Loop Tuning

When you use the Open-Loop PID Autotuner, if your controller includes integrator action,

consider implementing signal tracking to avoid integrator windup during the tuning

experiment. Signal tracking enables the PID controller to continue to track the real plant

input while it is out of the loop. Without it, your system can experience a bump when the

control loop is closed at the end of the tuning process.

If your PID controller is a Simulink PID Controller block, you can use the Enable

tracking mode parameter of the controller block to avoid this bump. The following

diagram illustrates a module containing an Open-Loop PID Autotuner block and a PID

Controller block with tracking mode configured. The plant input feeds into the tracking

input of the controller block.

For external-mode tuning, you configure the start-stop signal as described in “PID

Autotuning for a Plant Modeled in Simulink” on page 8-9. The models illustrated here use

a simple switch with a binary signal to start and stop the experiment manually.

8 PID Autotuning