A GEMMA-GRAFCET Methodology to enable Digital Twin based on Real-Time Coupling

Digital Twin (DT) represents the next wave in modelling, simulation and optimization technology. A key enabling technology of the DT is the real-time coupling of the digital models with the controllers of the physical plant. To implement the DT through real-time coupling, common approaches and vocabularies are desirable for the automation software to facilitate the exchange of information between the PLCs and the digital models. However, the scarce adoption of guidelines and standards within the industrial practice of PLC programming complicates this context. To face this challenge, this paper proposes a methodology for PLC code to standardize the vocabulary and the management of the operational modes of industrial automation systems. The methodology consists of a GEMMA-GRAFCET representation and a Hierarchical Design Pattern. By implementing the approach to a case study, it is demonstrated that the methodology generates a standard interface for the communication between PLCs and digital models within a DT architecture.