Backward Time Analysis for the diagnosis of discrete event systems

This paper deals with the diagnosis problem of discrete–event systems The proposed method is based on the model-checking technique, thanks to the time analysis of the dynamic model. A dynamic model with temporal transitions is proposed in order to found the origin of all possible faults. By “dynamical model”, we mean an extension of timed automata for which the faulty states are identified. The model of the studied system contains the faultless functioning states and all the faulty states. Our method is based on the backward exploitation of the dynamic model, where all possible reverse paths are searched. The diagnosis method is based on the coherence between the occurrence time of the fault and the reverse path length. A simple real-world batch process is used to demonstrate the modeling steps and the proposed backward time analysis method to reach the diagnosis results.