A simulation model based on a stochastic Petri net approach for dependability evaluation of Profibus-DP networks

The paper proposes a dependability model which enables the evaluation of Profibus-DP networks in scenarios of transient faults which affect data communications. The full behavior of Profibus-DP communication stack is modeled, including: cyclic process data exchange between master and slave stations; configuration, parameterization and diagnostics of slave stations. The model is based on a high level stochastic Petri net formalism referred as stochastic activity networks (SAN), supported by the Mobius tool. High modeling power, state-of-the-art analytical and simulation solutions, and a flexible and integrated environment are their main features. Dependability measures are established from the fulfillment of the real-time constraints (deadlines) defined on process data messages exchanged between master and slave stations. The reward concept is used to define the measures, which are obtained by means of a simulation approach. A case study is proposed to assess the model performance.