Control System is a set of mechanical or electronic devices that regulates other devices or systems by way of control loops. The Control System compares the value or status of the process variable (PV) being controlled with the desired value or set point (SP), and applies the difference as a control signal to bring the process variable output of the Plant to the same value as the set point. The major types of Control Systems are as follows; Open Loop Control System, Closed Loop Control System, Linear Control System, Non-Linear Control System, Time Variant Control System, Time In-Variant Control System, Continuous-Time Control System, Discrete-Time Control System and Feed Control System. Control Systems are used to continually regulate the behaviour of devices in a repeatable and predicted way. They may be simple electronic or electrical devices or very sophisticated computer-controlled systems.