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Network independent safety protocol for industrial controller

  • US 6,891,850 B1
  • Filed: 09/18/2000
  • Issued: 05/10/2005
  • Est. Priority Date: 12/22/1999
  • Status: Expired due to Term
First Claim
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1. A network-independent, high-reliability communications system for an industrial controller using a standard serial communications network, the communications system comprising:

  • a first I/O communications circuit receiving I/O data for control of an industrial process;

    a first network-independent protocol device receiving the I/O data and formatting it for transmission under a network-independent protocol to produce high-reliability formatted data formatted to reduce undetected transmission loop errors, the formatting including at least one of a cyclic redundancy code related to the I/O data and a sequence count related to the local order of transmission of the I/O data with respect to other I/O data being transmitted;

    a first standard network protocol device receiving the high-reliability formatted data and further formatting it for transmission under a protocol of the standard serial communications network, to produce doubly-formatted data for transmission on the standard serial communications network, the protocol of the standard serial communications network also formatting data to reduce undetected transmission loop errors, the formatting including at least one of a cyclic redundancy code related to the I/O data and a sequence count related to the local order of transmission of the I/O data with respect to other I/O data being transmitted, the cyclic redundancy code and sequence count being redundant with the cyclic redundancy code and sequence count of the first network independent protocol device;

    a second standard network-protocol device receiving the doubly-formatted data from the standard serial communications network and extracting the high-reliability formatted data according to the protocol of the standard serial communications network;

    a second network-independent protocol device receiving the high-reliability formatted data and extracting the I/O data; and

    a second I/O communications circuit receiving I/O data for control of an industrial process from the second network-independent protocol device;

    whereby high-reliability transmissions may be simply obtained on an arbitrary standard serial communications network protocol.

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