AUTOMATIC SAFETY ANALYSIS OF COMPUTER CONTROLLED PLANTS USING MODEL CHECKING

The paper describes an approach to apply the formal technique of model checking to the verification of logic controllers within the safety analysis of processing plants. In a first step the communication between the modules is represented graphically in a so-called Process Control Event Diagram (PCED), and the behaviour of each module is described in terms of logical expressions for the modules' input, state and output variables. Using a formal model specification, the method of model checking can be applied to algorithmically determine whether the system fulfils safety requirement, specifically if for a given controller the plant can reach dangerous states or not. Our approach is illustrated by application to an industrial computer-controlled tube reactor.