Process Control System Dec28

Process Control System...

Process Control System A process is broadly defined as an operation that uses resources to transform inputs into outputs. It is the resource that provides the needed energy to the process for the transformation to occur. In the context of an industry the term ‘process’ as used in the term ‘process control’ refers to the methods of changing and refining of raw materials that remain in a solid, liquid, gaseous, fluid or slurry state  to create end products of specified properties. The raw materials during the process are transferred, measured, mixed, heated or cooled, filtered, stored or handled in a way so that the desired output is obtained. During the process the raw materials undergo physical and chemical changes for their conversion into the end products. Normally an industry operates a number of processes where each process exhibits a particular dynamic (time varying) behaviour that governs the transformation. The dynamic behaviour is determined by the physical and chemical properties of the inputs, the resource and the process itself. Process control refers to the methods that are employed for controlling the variables of the process or processes used in the manufacturing of a product. It is the act of controlling a final control element to change manipulated variable to maintain the process variable at a desired set point. These variables can be in process inputs, in process parameters and in process output. Control of the process is done to reduce its variability for getting aimed product quality, improving the production rates, increasing the efficiency of the process, facilitating protection of the environment and ensuring safety of the men and equipment employed for the process. A corollary to the process control is that a controllable process must behave in a predictable manner. For a given change...