Monitoring of Timed Discrete Events Systems With Interrupts

A framework is introduced for monitoring the interrupting faults in the timed discrete events systems. We introduce the notion of acceptable behavior of the system subjected to these faults: permanent or intermittent. The acceptable behavior of a system is modeled by a stopwatch automaton. The timed sub-spaces in the locations of the automaton delimit exactly the range of the acceptable behavior. They are synthesized using the techniques of reachability analysis of stopwatch automata in a way to detect the system faults as early as possible. Note to Practitioners-The final monitoring system is a stopwatch automaton. This automaton can be translated into a Sequential Function Chart (SFC), an industrially recognized and used tool of programming logic controllers (PLCs). Consequently, we can implement the proposed monitoring system by the PLC, used extensively in the industrial environment.