A safety controller for a control system configured to run a controlled process, the safety controller comprising: an interface circuit , configured to couple to input/output devices that are coupled to field devices including sensors and actuators that are coupled to processing equipment involved in said controlled process; a primary controller including a processor having an associated memory and a parallel connected secondary controller including a secondary processor having an associated secondary memory , each configured for implementing control loops that automatically take actions by sending control signals to said actuators; a mode-switching multi-key switch coupled to said processor ; a bus coupling said interface circuit and said mode-switching multi-key switch coupled to said processor, said multi-key switch comprising: a force, FRC, enable key-switch having a FRC enable On position, wherein said FRC enable On position is configured to allow said safety controller to enter a maintenance override mode to enable entry of maintenance overrides and the FRC enable key-switch having a FRC OFF position, wherein said FRC OFF position is configured to change a safety controller state back to a run mode, said FRC OFF position preventing changes to said maintenance override mode by prohibiting additional maintenance overrides until said FRC enable key-switch is set to said FRC On position again, and a FRC reset key-switch having a FRC reset position for removal of said maintenance overrides entered when in said maintenance override mode. an interface circuit , configured to couple to input/output devices that are coupled to field devices including sensors and actuators that are coupled to processing equipment involved in said controlled process; a primary controller including a processor having an associated memory and a parallel connected secondary controller including a secondary processor having an associated secondary memory , each configured for implementing control loops that automatically take actions by sending control signals to said actuators; a mode-switching multi-key switch coupled to said processor ; a bus coupling said interface circuit and said mode-switching multi-key switch coupled to said processor, said multi-key switch comprising: a force, FRC, enable key-switch having a FRC enable On position, wherein said FRC enable On position is configured to allow said safety controller to enter a maintenance override mode to enable entry of maintenance overrides and the FRC enable key-switch having a FRC OFF position, wherein said FRC OFF position is configured to change a safety controller state back to a run mode, said FRC OFF position preventing changes to said maintenance override mode by prohibiting additional maintenance overrides until said FRC enable key-switch is set to said FRC On position again, and a FRC reset key-switch having a FRC reset position for removal of said maintenance overrides entered when in said maintenance override mode. a force, FRC, enable key-switch having a FRC enable On position, wherein said FRC enable On position is configured to allow said safety controller to enter a maintenance override mode to enable entry of maintenance overrides and the FRC enable key-switch having a FRC OFF position, wherein said FRC OFF position is configured to change a safety controller state back to a run mode, said FRC OFF position preventing changes to said maintenance override mode by prohibiting additional maintenance overrides until said FRC enable key-switch is set to said FRC On position again, and a FRC reset key-switch having a FRC reset position for removal of said maintenance overrides entered when in said maintenance override mode. <EOS>