Response time evaluation of industrial-scale distributed control systems by discrete event systems formalisms

Abstract

This research deals with the temporal performance analysis of distributed networked automation systems. It describes a new formal approach that estimates the maximum limit of response time in Networked Control Systems (NCS) that use a producer/consumer protocol. Two different tools of discrete event systems have been used: Timed Event Graphs (TEGs) and (Max,+) algebra. First, the contribution is to model all components of NCS with TEGs, and to represent the behaviour of these graphs by (Max,+) linear equations, and then to determine the upper bounds of the response time by an analytical formula. The main novelty of these results is to introduce a modular method capable of providing crucial validation elements regarding temporal performances for an industrial scale NCS that includes inter CPU communication. Moreover, the modular aspect of the presented approach remains in considering the end-to-end delays introduced by the network as model parameters, calculated from other models.