Due to the rapid advances in technology, all industrial processing systems, factories, machinery, test facilities, etc. turned from mechanization to automation. A mechanization system needs human intervention to operate the manual operated machinery. As new and efficient control technologies evolved, computerized automation control is being driven by the need for high accuracy, quality, precision and performance of industrial processes.Automation is step beyond the mechanization which makes use of high control capability devices for an efficient manufacturing or production processes.

The word ‘Automation’ is derived from ancient Greek words of Auto (means self) Matos (means moving). Thus, a mechanism move by itself or self dictated is called automation. As compared with manual systems, automation systems provides superior performance in terms of precision, power and speed of operation. Industrial automation is the use of control devices such as PC/PLCs/PACs etc. to control industrial processes and machinery by replacing as much as possible labour intervention and dangerous assembly operations with automated ones.

In industrial control a wide number of process variables such as temperature, flow, pressure, distance, and liquid levels can be sensed simultaneously. All these variables are acquired, processed and controlled by complex microprocessor systems or PC based data processing controllers.

Control systems are the essential parts of an automation system. The various types of closed loop control techniques ensure the process variables to follow the set points. In addition to this basic function, automation system employs different other functions such as computing set points for control systems, plant start up or shutdown, monitoring system performance, equipment scheduling, etc. The control systems along with monitoring adapted to the operating environment in an industry for flexible, efficient and reliable production system.