Control System - Elements

Example: Auto switch off motor when tank is full.

Example: PWM based controller for controlling rpm of a motor.

It is device that produces a control signal consisting of two terms: one is proportional to error signal and the other is proportional to integral of error signal.

A PD controller is used to make a simple system track some reference point.

Example:

In the car suspension system, the spring and damper work together to hold the car at some desired height. The spring exerts a force proportional to its deflection, while the damper opposes motion (the derivative of deflection).

PID controller is an instrument used in industrial control applications to regulate temperature, flow, pressure, speed and other process variables.

They are the most accurate and stable controller.

Example:

PID temperature controller, has a temperature sensor (thermocouple) as input and compare the actual temperature to the desired control temperature. It will then provide an output to a control element.