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Microcomputer based distributed control network

  • US 4,539,655 A
  • Filed: 03/16/1982
  • Issued: 09/03/1985
  • Est. Priority Date: 03/16/1982
  • Status: Expired due to Fees
First Claim
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1. A fault tolerant distributed network process control and communications network system for controlling and/or monitoring a plurality of work stations comprising:

  • (a) a plurality of nodes for selected work stations each adapted to monitor or control individual work stations inter-connected by communications network means, each node including;

    (i) processor means dedicated to network communication and process I/O;

    (ii) network control means for controlling inter-node protocol communications and further including clocking means and error detection and correction means;

    (iii) communications interface logic means for interfacing between the communications network and the network control means and further including clocking means and error correction and detection means for reshaping and resynchronizing the transmitted signal at each communication interface logic means;

    (b) said communications network means interconnecting said network node and said plurality of nodes;

    said network communication means having two primary channels (A and B) in a first communications media which operate to simultaneously transmit data between the said nodes in opposite directions and a third back-up channel (C) which is normally on standby;

    (c) said communications interface logic means upon failure of channel A or B being operable to switch to the other of channel A or B and channels A and B will fold back on themselves with data also being transmitted on the nonfailed channel A or B, whereby transmitted data will pass through all nodes in the network regardless of message destination;

    (d) said network control means and said communications interface logic means upon failure of channels A and B being operable to switch to channel C; and

    (e) said communications interface logic means including means continually monitoring channels A, B and C whereby upon fault correction, said error detection and correction means prioritize communications to channel A.

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