Patent ID: 7290170

Claim:
A method for providing arbitration for redundant controllers comprising: providing logic for automatically determining which controller of redundant controllers is active controller, wherein outputs controlled by the redundant controllers are electrically connected together and provided as input to at least one device; providing an independent hardware interlock device coupled to the outputs of the redundant controllers to ensure that output controlled by only the active controller is enabled as input to the at least one device, the independent, hardware interlock device being separate from and external to the redundant controllers; wherein providing the independent, hardware interlock device includes providing a hardware state machine to enable/disable outputs controlled by each controller of the redundant controllers and ensure that output of only the active controller is enabled as input to the at least one device; further comprising employing a watch dog timer for each controller of the redundant controllers, and providing status of watch dog timer signals of the redundant controllers to the hardware state machine as input, wherein the hardware state machine employs the status of the watch dog timer signals of the redundant controllers to determine which controller of the redundant controllers to have output enabled for input to the at least one device; and wherein providing the independent, hardware interlock device includes providing the hardware state machine for each controller of the redundant controllers, and wherein each hardware state machine further employs as input a unique identification of the associated controller.