Open up the "Controller" subsystem. Notice that this model uses a Triggered Stateflow® Chart to do the "Enable" and "Setpoint" calculation. It uses a discrete PID Controller to compute the "Throttle Command".
You can generate PLC Structured Text code for this subsystem by right-clicking on the subsystem block and select PLC Code -> Generate Code for Subsystem Alternatively, you can use the following command generatedFiles = plcgeneratecode('plcdemo_cruise_control/Controller');
After the code generation, the Diagnostic Viewer window is displayed with hyperlinks to the generated code files. You can open the generated files by clicking on the links.