In this paper, an algorithm is proposed for on-line real-time diagnosi
s of faults that cannot be diagnosed by conventional algorithms. Pulse
-type failures or failures involving oscillating state variables, for
example, can be diagnosed, and with far less memory than by a multista
ge algorithm in which the number of stages increases with fault prolif
eration. Through the use of a cause-effect matrix, possible fault prol
iferation paths can be rapidly calculated by a Boolean.