## 6 Discussion
However, these technologies are still widely used in industrial practice, and one of this study's objectives was to evaluate their behaviour, interoperability, and limitations within the virtual commissioning process. Understanding the constraints of legacy systems is essential for assessing migration strategies and ensuring compatibility with contemporary automation solutions. Based on these findings, future work will focus on integrating the S7-1500 series PLCs, OPC UA, and SIMIT to develop and validate behavioural models in a more advanced and scalable automation environment. These upgrades will allow for a more precise representation of system behaviour and improve the interoperability of virtual commissioning tools with modern industrial applications. Despite its limitations, the future of industrial automation lies in digital enterprise and virtual commissioning. The benefits outweigh the challenges, as the objectives outlined above are achievable with continuous advancements in simulation and automation technologies. In this study, the assembly system was successfully replicated and functionally validated in Tecnomatix Process Simulate, demonstrating the potential of virtual commissioning. One key strategy for reducing time and costs is the adoption of \"Smart Components\" provided by suppliers, like the widespread availability of CAD models today. Standardizing behaviour models, kinematic models, and parameter customization would significantly improve simulation efficiency, aligning with Industry 4.0 standards. The results of this study should be interpreted in relation to previous research and established working hypotheses. The findings demonstrate that virtual commissioning effectively enhances the design, validation, and optimization of assembly systems, contributing to the broader field of digital manufacturing. However, further research is needed to refine kinematic modeming, real-time simulation accuracy, and seamless PLC integration. Future studies should focus on developing automated methods for kinematic model generation, improving real-time synchronization between simulation models and physical systems, and exploring the interoperability of different virtual commissioning tools. These advancements will drive the continuous evolution of smart manufacturing and further enhance the implementation of Industry 4.0 technologies. During the virtual commissioning process, we encountered several challenges that highlighted key areas for further research and optimization. One of the most significant findings was the impact of the integrator's experience level on digital twin preparation time. While experienced users were able to streamline the setup efficiently, less experienced users required significantly more time to achieve the same level of accuracy. This variability suggests that developing standardized workflows and automation tools could further enhance the efficiency of virtual commissioning. Additionally, we observed that not all signals used in real industrial projects are visually represented in the 3D model. Certain system components, such as communication signals, printer interactions, and safety protocols, do not have direct graphical counterparts but are still crucial for system functionality. Our study confirmed that virtual commissioning can effectively test both graphical and non-graphical signals, which broadens its applicability beyond visual simulation. To address these challenges, future research will explore advanced software tools such as WinMOD and SIMIT, which specialize in signal validation and system behaviour simulation beyond purely graphical models. Furthermore, a comparative study between Delmia and Process Simulate will be conducted to evaluate their suitability for different industrial applications.