Industrial controllers with highly distributed processing and method of programming same

摘要

A highly distributed industrial control system employs a number of separate control modules (12) communicating together on a shared communications medium (14). Each module (12) emulates one or more basic electrical parts having electrical terminals, such as switches and relays, and transmits production messages indicating the state of the parts, such as conducting current or not. A connection list for each part in each control module (12) defines message identifiers of other parts whose production messages are received by the control module (12) and interpreted as current flow to one or more of its parts. The control system is programmed by generating a schematic on a programming terminal (20) showing connections of terminals on symbols of the parts such as would represent actual wiring of the emulated parts. A parts layout diagram is used in conjunction with the schematic to identify each part to a physical module. In this way the program is divided to run concurrently on the various modules (12) without explicit instructions by the programmer.