On a Novel Approach of Fault Detection in an Easily Testable Sequential Machine with Extra Inputs and Extra Outputs

By augmenting a given sequential machine M with two extra input symbols Ie1 and Ie2 and with one extra output terminal Z´, a method is developed in this paper for designing an efficient checking experiment for the machine M and for its fault diagnosis to cover the types of faults which may result in an increase in the number of states of the original machine M. The method is an extension of the works of Fujiwara et al.[6], and the scheme of modification never alters the modified machine M´ from its easily testable nature as defined by Fujiwara et al [16]. The checking sequences exhibit remarkable savings of the number of input symbols for many sequential machines having a large number of states as compared to that of Fujiwara et al [16].