Use of a dedicated computer (known as a process controller) to control a specific industrial or manufacturing process. Information (sensed) from that process is used as a source of data; computations made upon that data determine control signals to be sent to the process. The computations may involve some statistical properties (such as moving average) for statistical process control.
In general there are two forms of process control: continuous and discrete. Continuous process control is involved with the manufacturing of some form of continuous product, primarily chemicals, an example being the automatic control of a catalytic cracker for petroleum distillation. Although chemicals may be manufactured in batches, this is still considered a continuous process since the variables that control the process can be varied continuously. Discrete control is concerned with the manufacturing of individual (discrete) items, as in the welding of two parts to form a larger assembly. Discrete process control has strong connections with industrial robotics. See also numerical control, computer-aided manufacturing, computer-integrated manufacturing.