INDUSTRIAL CONTROL SYSTEM

Industrial Control System

Industrial Control System

Literature Review

The control system is that means by which any quantity of interest in a machine, mechanism or other equipment is maintained or altered in accordance with a desired manner (Karen, et al 2012, pp. 151-153). Consider, for example, the driving system of an automobile. Speed of the automobile is a function of the position of its accelerator(David, et al. 2009, pp. 45-51). The desired speed can be maintained (or a desired change in speed can be achieved) by controlling pressure on the accelerator pedal. This automobile driving system (accelerator, carburettor and engine-vehicle) constitutes a control system (Karygiannis, 2011, pp. 133-136).

It is instructive to trace brief historical development of automatic control. Automatic control systems did not appear until the middle of eighteenth century. The first automatic control system, the fly-ball governor, to control the speed of steam engines, was invented by James Watt in 1770 (Franz, 2012, pp. 333-338). This device was usually prone to hunting. It was about hundred years later that Maxwell analyzed the dynamics of the fly-ball governor(Richard, et al. 2011, pp. 269-271). The importance of positioning heavy masses like ships and guns quickly and precisely was realized during the World War I(David, et al. 2009, pp. 45-51). In early 1920, Minorsky performed the classic work on the automatic steering of ships and positioning of guns on the shipboards (Karen, et al 2012, pp. 151-153). A date of significance in automatic control systems in that of Hazen's work in 1934. His work may possibly be considered as a first struggling attempt to develop some general theory for servomechanisms. The word 'servo' has originated with him (Franz, 2012, pp. 333-338). Prior to 1940 automatic control theory was not much developed and for most cases the design of control systems was indeed an art. During the decade of 1940's, mathematical and analytical methods were developed and practised and control engineering was established as an engineering discipline in its own rights (Karygiannis, 2011, pp. 133-136). During the World War II it became necessary to design and construct automatic aeroplane pilots, gun positioning systems, radar tracking systems and other military equipments based on feedback control principle. This gave a great impetus to the automatic control theory(Richard, et al. 2011, pp. 269-271).

It is important to note that the actual missile launching and guidance system is far more complex requiring control of gun's bearing as well as elevation. The simplified case discussed above illustrates the principle of feedback control (David, et al. 2009, pp. 45-51). The industrial use of automatic control has tremendously increased since the World War II. Modern industrial processes such as manufacture and treatment of chemicals and metals are now automatically controlled(Karen, et al 2012, pp. 151-153).

Critical infrastructures, such as electricity generation plants, transportation systems, oil refineries, chemical factories and manufacturing facilities are large, distributed complexes. Plant operators must continuously monitor and control many different sections of the plant to ensure its proper operation (Karygiannis, 2011, ...