A modular PLC simulation method for virtual replication of a cost-effective industrial automation laboratory

Access to hands-on PLC training is often limited by the cost and complexity of physical automation laboratories, while existing simulation tools typically lack alignment with real hardware configurations, reducing their effectiveness for education. To address this, we present a modular PLC simulation method that enables accurate virtual replication of a cost-effective, scalable industrial automation laboratory used for traffic light control, elevator operation, and automated filling systems. Built in Unity, the method integrates a custom ladder logic execution engine with interactive 3D models that mirror the exact input/output structure and operational behavior of the physical laboratory. Users can program, test, and debug logic in a realistic environment and receive immediate visual feedback—without requiring hardware. The method was validated by comparing its outputs against the physical system across 4 representative automation tasks; in every case, the virtual and physical setups produced I/O sequences matching within ±10ms and control outcomes, confirming functional equivalence. • Introduces a modular simulation framework that faithfully replicates the application scope of a physical low-cost PLC training laboratory. • Combines a custom ladder logic interpreter with real-time 3D visualization in Unity to enable program testing and debugging. • Validates functional equivalence through direct behavioral comparison with physical hardware across 4 standard automation tasks.