Industrial communications network with mastership determined by need
December 12, 1999. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3445822 Modularly addressable units coupled in a data processing system over a common bus Memory unit for connection to central processor unit and interconnecting bus Polling and data communication system having a pulse position to binary address conversion circuit Communications bus monitor Apparatus for selective control of information between close and remote stations Digital output control circuit Patent #: 4172280 InventorsAssigneeApplicationNo. 06/102970 filed on 12/12/1979US Classes:710/109, Bus polling700/2, Plural processors700/9Supervisory controlExaminersPrimary: Zache, Raulfe B.Attorney, Agent or FirmInternational ClassesG05B 19/05 (20060101)G06F 13/36 (20060101) G06F 13/20 (20060101) G06F 13/22 (20060101) G06F 13/372 (20060101) G06F 13/368 (20060101) AbstractAn industrial communications network includes microprocessor-based interface circuits which each connect a controller such as a programmable controller to a high speed serial data link. Each interface circuit connects to the data link and its associated controller, and each is operable to receive messages on the data link directed to its associated controller. In addition, each interface circuit can assume mastership of the communications network when the existing master generates a poll command indicating it is ready to relinquish mastership. As a result, the communications network will continue to function even though one or more controller or their associated interface circuits become inoperable.Other References
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