## 2 State of the Art
### ABB RobotStudio
One of the many challenges posed by this new technology is the software integration of the DT simulation models into a simulation that contains the entire PLM system. Functional Mock-Up Interface [24] is a technology that makes this integration possible by creating a standard for exchanging models for functional simulation. This is introduced as a functional model unit (FMU). FMUs represent a uniform interface through which model integration and pure co-simulation with a common reservoir of equations are allowed. Once an event detection function is implemented, variable value jumps can also be detected. In order to increase the accuracy of the simulation, these areas can be simulated with a higher temporal resolution. This standard can accept behavioral models for both time and control in closed and open loops. For example, Stateflow and Simulink can be integrated, as well as simulation models containing multiple bodies. In conclusion, it can be used for the integration of DT [24]. In order to guarantee the protection of the contained intellectual property, the encapsulation of the simulation models in UMF is employed. However, if enough effort is made, the protection in question can be avoided. If DT hitch models are used, they are based on sensitive algorithms [25] and their protection must be guaranteed. In summary, while these protective algorithms are not initially included in the DT transmission, they become essential during execution, requiring integration with simulation models, and subsequently, they operate on servers. Following the technical integration of the DT, it becomes imperative to synchronize the altered data for these models [26]. In practice, the IMF may encounter challenges during data exchange between models, leading to potential failures, despite its ability to operate independently of tools. This includes the simulation of the installation, among other functionalities [27]. Therefore, DTs need to ensure that the provision of relevant data is understood by other DTs in the same way. Therefore, the meaning that a data value will take will be clearly different. It is necessary to understand the data in as much detail as possible. Virtual Universe Pro is a simulation software for automation items. It is employed to simulate, view, and interact with another system. From a customizable object library or by importing a full model from a main CAD system (SolidEdge, Catia, SolidWorks [28], Inventor), based on the 3D file format--3D, 3 DXML, OBJ, etc.--a simulation can be created. The entire simulation is capable of running in real-time, controlled by a PLC in a built-in virtual controller, and connected to the PC or software that uses an IP connection [29; 30]. TwinCAT 3 CAD Simulation Interface is another computer software tool that can use a link between 3D CAD offline simulation systems, such as RS and TwinCAT. The conclusion is that this connection is a software-in-the-loop (SIL) simulation of the sequences that will be implemented on automated equipment to help the real operation. From the hardware point of view, the PLC represents an element that is part of the control process and changes real signals. At the same time, the component is integrated into the virtual environment of RS, to write and read the virtual signals that control the virtual environment [31]  
[PERSON] et al., 2024 [32] provided experimental results of the proposed architecture integrating the digital twin with the manufacturing execution system (MES), demonstrating that the system improves interoperability across various control subsystems, enlightening the management and the analysis of processes through manufacturing devices. Moreover, the DT enables the detection and diagnosis of issues during process execution. In industrial settings, disturbances--both internal and external--can lead to production line downtime, but the advantages of DTs allow for quicker identification of these errors compared to conventional systems, significantly reducing the downtime.