PID controller

Before explaining about the PID controller, it is good to know that the controller is basically responsible for comparing the actual value of the process with the desired value or set point, as well as issuing a command to the actuator to perform this setting. For example, in simple controllers such as thermostats, the sensor that is responsible for measuring temperature is usually composed of a bimetal, and in fact this bimetal is inclined to one side due to temperature increase or decrease with proper adjustment for the desired temperature of the controller output. The same command is issued to turn off or on the heat source. Temperatures that the use of simple controllers cause constant temperature fluctuations.