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Abstract

A method and apparatus for providing an active standby control system comprising the steps of providing a first programmable logic controller and a second programmable logic controller, each controller having an operating state. A sub-network is formed by operably connecting the programmable logic controllers to an IO module with a fiber optic cable and a network connector. Data is transmitted over the sub-network at a rate of at least 100 Mb/s. A network identifier, i.e., Internet Protocol or Media Access Control address, is associated with each programmable logic controller. The network identifier of each controller is determined in response to the operating state of the respective programmable logic controller. The network connector can be a switch or a hub to assist in avoiding signal collisions and maintaining determinism on the sub-network.

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First Claim