Patent ID: 8769158

Claim:
A backplane for an industrial control system comprising: an adapter base module having a first port, a second port, a switching node and a network adapter, the switching node coupled between the first port and the second port and in communication with the network adapter, the network adapter operable to communicate over a control network; a plurality of I/O base modules, each I/O base module having a first port, a second port and a bus slot, the bus slot for releasably receiving a function card having a switching node, wherein each I/O base module couples the first port and the second port to the switching node when the function card is installed in the bus slot, and each I/O base module couples the first port to the second port when the function card is absent from the bus slot; and at least one I/O base module having a function card installed in the bus slot; wherein the second port of the adapter base module is coupled to the first port of an I/O base module, and the second port of each I/O base module is coupled to the first port of the next I/O base module, except the last I/O base module, and the adapter base module and the plurality of I/O base modules each have a third port and a fourth port that are coupled together, wherein the second port of the last I/O base module is coupled to the third port of the last I/O base module, and the fourth port of each I/O base module is coupled to the third port of the previous I/O base module, except the first I/O base module having the fourth port coupled to the third port of the adapter base module, the fourth port of the adapter base module coupled to the first port of the adapter base module to form the network ring.