INDUSTRIAL CONTROLLER EMPLOYING THE NETWORK RING TOPOLOGY

摘要

A network for an industrial control system employs a ring topology that is normally opened by a ring supervisor at the ring supervisor. Upon failure of the network, the ring supervisor reconnects the ring to provide an alternative transmission path around the failure point. High speed operation is reconciled with the ability to use commercial switching integrated circuits through a dual communication channel of communicating a network state as either closed or open using both high-speed hardware handled beacon frames and low-speed software processed announce frames.