Allen-bradley Company, LLC

Donald S Pieronek

Mark A Lucak

Jonathan R Engdahl

David J Gee

John J Hodorowski

Hassan A Chami

A highly distributed industrial control system employs a number of separate control modules communicating together on a shared communications medium. Each module 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 defines message identifiers of other parts whose production messages are received by the control module 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 showing connections of terminals on symbols of the parts such as would represent actual wiring of the emulated parts. This schematic is analyzed to determine the immediate upstream neighbors of each part and the message identifiers of those parts in the control modules form the connection lists. In this way the program is divided to run concurrently on the various modules.

Industrial controller with highly distributed processing

Each message carried by a communication network has a packet that contains data, a tag, and a generation count wherein duplicate packets sent in different messages have identical generation counts. A station includes a modem that connects to the communication network in order to receive messages. A fixed screener circuit has a first memory that stores a set of tag values and a fixed screener determines when a packet tag matches a tag value in the first memory. The station also has an interface through which tag values are received from an external device, such as a host computer. A general purpose screener includes a second memory with a plurality of storage locations in which to store tag values from the interface and a generation count associated with each tag value. A first comparator in the general purpose screener determines when a tag contained in a packet matches a tag value in the second memory, and a second comparator determines when a generation count in the packet matches the generation count in the second memory that is associated with the matching tag value. A control circuit produces a signal when the first comparator indicates a tag match and the second comparator indicates that the generation counts do not match. The station ignores the packet in the absence of the signal.

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Waukesha County, WI, United States of America

Donald S Pieronek