Safety network for industrial controller providing redundant connections on single media
AssigneeRockwell Automation Technologies, Inc.
InventorsKerry W. Vandesteeg, David A. Vasko, Joseph A. Lenner, Kenwood H. Hall
Life of this patent
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Abstract
A highly reliable industrial control system is produced by opening multiple connections on a connected messaging network running a standard serial protocol. The two connections are used to transmit redundant data and include a reply message to the message producer. Errors in the messages or media failure may be detected using standard error detection codes, retry counters and deadman timers. Comparison of the data of the two messages can reveal other types of failure not apparent by these former techniques.
Claims23
A method of establishing high reliability communication among components of an industrial controller some of which receive control signals from a controlled process, the components communicating over a standard network, the method comprising the steps of:
- (a) establishing at least two redundant logical message producers associated with a given received control signal;
- (b) opening a logical connection between each of the two logical message producers and two corresponding logical message consumers;
- (c) transmitting data including a given received control signal on the connections from the logical message producers to the logical message consumers;
- (d) after receipt of the uncorrupted data at each logical message consumer, transmitting reply data including the given received control signal on the connection to the logical message producers;
- and
- (e) responding at the logical message producers to an absence of an uncorrupted receipt of a transmission of reply data subsequent to step (c) on the connection by entering a predetermined safety state.
A method of establishing high reliability communication among components of an industrial controller some of which output control signals to a controlled process, the components communicating over a standard network, the method comprising the steps of:
- (a) establishing at least two redundant logical message producers associated with a given received control signal;
- (b) opening a logical connection between each of the two logical message producers and two corresponding logical message consumers;
- (c) transmitting data including a given output control signal on the connections from the logical message producers to the logical message consumers;
- (d) after detection at the logical message consumers of uncorrupted data including the given output control signal transmitting reply data including the given output control signal on the connection to the logical message producers;
- and
- (e) responding at the logical message consumers to an absence of an uncorrupted receipt of the data subsequent to step (d) within a periodic interval by entering a predetermined safety state.
Dependencies are inferred from the claim text.