Popular industrial processes are chemical, petrochemical, fertilizer, power, metallurgical, food processing, pharmaceutical, etc. In any ‘process’, productivity with assured quality is the most important aspect. Automation techniques are increasingly being incorporated in various processes to increase productivity with desired quality. To operate an industrial process in a desired manner, control of its operation is needed at every possible step. Control engineering, as one of the cornerstones of automation, enables automation tasks to be accomplished physically. In modern industrial automation networks, usually a five-layered communication hierarchy model is used. It describes the equipment required, network architecture, communication modes between equipment, and the nature of information flow and its control. Based on the integration level and flexibility, the industrial automation systems may be classified into three basic categories: fixed automation, programmable automation, and flexible automation.