Industrial process control system

Abstract

An industrial process control system in accordance with the present invention includes a plurality of device controllers connected together through a common buss with each device controller connected to an associated controlled device(s) that effect process control. A computer-aided system interface for controlling the overall system includes a visual display device in the form of a multi-color CRT and a graphic input device in the form of a transparent touch-responsive panel that overlies the CRT display screen. Computer generated symbols representing the controlled devices are displayed on the CRT screen to define touch-responsive target areas. When an appropriate target area is touched by a human operator, a signal, such as a command signal, is generated to cause the controlled device whose symbol is displayed in the designated target area to respond, with this response being then indicated by a change in the device symbol being displayed on the screen. Other features include generation of a 'hit' display to indicate the last coordinates on the display screen touched by the operator, a two-step execute command sequence for entering high priority commands into the system, and the changing of analog set point values as a function of the time that a selected target area is touched. The system advantageously eliminates some, if not all, input through a conventional keyboard so that the system operator interfaces with the system through easily comprehended and non-ambiguous visual symbols.