A Digital Twin Framework for Programmable Logic Controllers in Industrial Automation Systems

The integration of industrial automation systems, particularly programmable logic controllers, has proven to be complex due to heterogeneous hardware, proprietary programming environments, and interoperability challenges. To address these issues, this work presents a digital twin framework for PLCs, enabling live monitoring, control, programming, and simulation. The framework is designed to comply with the IEC 61131-3 norm and utilizing standardized communication protocols such as OPC UA, ensuring interoperability and reducing integration costs. By incorporating Virtual Reality interfaces, the system facilitates interaction with automation environments, allowing engineers to visualize, configure, and validate PLC control logic before deployment. The utilization of a structured Asset Administration Shell model ensures a standardized representation of PLC data, enabling real-time synchronization between digital and physical counterparts. The framework also supports bidirectional communication, allowing live adjustment of control logic and system states. A prototypical implementation demonstrates the feasibility of the approach, with experimental validation showcasing the successful integration of PLC digital twins within a MotionDeviceSystem , as defined in the OPC UA Companion Specification for Robotics.