Patent US 3,971,000

An industrial process control system including a digital computer arranged in a time-share configuration to perform calculations respecting a plurality of process conditions, and to produce corresponding command signals for respective process operators such as valves and the like. The system includes an operator's console unit having a CRT display controlled by a local memory controllable by a keyboard, and by the computer in response to action from the keyboard. Special process-oriented displays can be presented on the CRT, such as fill-in-the-blanks forms into which the operator can insert new values, or other information. The keyboard includes a number of distinctive function keys which serve, in cooperation with the special CRT displays, to present information to the computer for processing, to aid in controlling the process.