25 Years Ago

The thought of using digital computers for process control emerged in the 1950s. The aerospace company, TRW, and the oil company, Texaco, made a feasibility study for computer control of a polymerization unit at the Port Arthur refinery in Texas. A computer-controlled system was designed based on the computer RW-300. A special-purpose digital computer for process control, the IBM 1700, was developed by IBM. This computer was installed at American Oil in Indiana, at Standard Oil of California, and at Du Pont in 1961.The installations at the oil companies were operated for many years. A new standard computer for process control, the IBM 1710, was announced in early 1961. The pioneering work done was observed by many process industries and computer manufacturers who saw potential productivity increases and new markets for computers.The paper revisits the early development of computer controlled systems in process control. To discuss the dramatic developments that followed, it is useful to introduce three periods: the pioneering period, the direct digital control (DDC) period, and the microcomputer period.