A control system is an interconnection of components forming a system configuration that will provide a desired system response. Control may also be called as measurement of desired system or any quantity of interest to be set at constant or desired level and system means the collection or aggregation of the part, mechanism or sub system working together to perform a desired task.
The basis for analysis of a system is the foundation provided by linear system, which assumes a cause effect relationship for the components of system. A component or process to be controlled can be represented by a block diagram as shown in figure below,
|Control System -Block Diagram|