Machine identification concepts of path sensitizing fault diagnosis

The automata roots of path sensitizing fault diagnosis are discussed. It is demonstrated that the path sensitizing diagnosis method is equivalent to a Moore type "machine identification" experiment for a machine class which contains good and faulty copies of a transmission path submachine of a complete machine. The maximum length of a complete set of path sensitizing tests for a machine is proporational to n, the number of states in the complete machine, rather than n2 as required by direct use of the Moore "machine identification" method without partitioning of the complete machine into a set of submachines. For memoryless irredundant machines the fault resolution power of a complete set of path sensitizing tests is, nevertheless, the maximum which is possible if no submachine with a fault is used as a sensitizing vehicle. The use of the path sensitizing method in irredundant sequential machines with memory, on the other hand, may not yield the maximum fault resolution power since those faults which have been grouped together in the faulty copy of a particular transmission path submachine may be distinguishable from each other.