Abstract: A method and system for processing signals in a protection system involves executing operations on signals that are complimentary to each other, such that the results of the operations determines whether the operations can be continued. Logic operations are performed and controlled variables, and complimentary operations are performed and controlled by state machines which trigger one another, to configure the system as a "house of cards" architecture, such that the entire correct functioning of the system of cooperating state machines is disabled when something goes wrong with one of the state machines.