A typical proportional, integral, and derivative (PID)
controller consists of a stand-alone regulator (which adjusts the
control variable of a process), a front end where the controller
constants are manually entered, and a processor (or a computer)
where the control algorithm is implemented. When a controller
observes deviations in a process output from predefined reference
values, the regulator automatically adjusts the process parameter
to compensate for such deviations. The regulator is a mechanical,
electrical, or an electromechanical system that implements...