On-Set Realization of Fail-Safe Sequential Machines

Fail-safe sequential machines can be constructed in such a way that if a failure happens in the sequential part, the ulterior functioning must carry on outside the code chosen to represent the set of states. This paper presents a study of the failures in the input combinational circuit and of the feasibility conditions of sequential machines with states coded by a k-out-of-n code. The electronic circuit is realized in a classical way (on-set realization) and must obey two hypotheses, 1) no failure on clock line C, and 2) single fault (stuck at 0 or stuck at 1) on other connections than C.