The application of the hierarchy system to on-line process control

With the acceptance of a computer for the control of separate on-line processes, consideration must now be given to extending such a control system to complete plants. The use of a single composite computer unit for this purpose is not generally practical, and an alternative approach to the problem is discussed. This uses a number of self-contained control units which are interconnected to form a hierarchy system. The pattern of control so formed is analogous to a conventional management structure. To illustrate the principles involved and demonstrate their application an integrated control and data handling system for a steel works is described.