Fault-tree structures of override control systems

The development of a systematic fault-tree synthesis procedure for the override control systems is presented in this paper. The unique configuration of the digraph model under study is first described and then analyzed in detail. On the basis of qualitative simulation of the fault propagation patterns, the corresponding generalized fault-tree structures are then established. It can be observed clearly from the simulation results that none of the existing techniques are capable of producing the correct fault-trees. To demonstrate the correctness of our analysis, successful application of the proposed structure to furnace operation is also presented.