## Incremental controller development

When developing a controller, it is often best to start with just a small part of the system.

You first develop a controller for that small part, and verify and validate it to make sure it works properly. Then, you extend the controller to work for a larger part of the system, and you keep repeating this until the controller controls the entire system. That is, you go through the entire development process (including among others specification, synthesis, verification/validation, implementation) each time. And then you increase the part of the system covered by the plants and requirements for each iteration. Typically, for low-level controllers you should start with no more than a few sensors and actuators, with their corresponding events.

This incremental development approach makes it easier to for instance figure out why your controller doesn’t behave as expected, which of your requirements are conflicting, or for what other reason a supervisor can’t be synthesized.