# When Operation Technology Meets Information Technology: Challenges and Opportunities
## 4 A typical Use Case
### Case Study  
In the depicted scenario, a conveyor belt is composed of two convergent lines, each one associated with a subset of visual cameras. Each camera is connected to the industrial physical switch via Ethernet for data communication and for clock synchronization. On the whole, the cameras constitute a vision system that collects images of the packages streaming on the conveyor belt. The information provided by this vision system is then processed by the business logic, taking into account other factors related to the manufacturing plant in order to control the speed of the two lines and the non-uniform distribution of packages on the belts.  
Industrial cameras can be used to achieve visual recognition of objects and packages streaming on the conveyor belts--that is, when a package passes through an area, information regarding the speed of the belt can be processed by business logic. In this scenario, the two different belts in an ideal situation should run at the same speed; however, in a real-world situation, the speed depends on various factors such as the performance of the devices, the temperature of the belt, safety checks on the system, etc. In that case, the various cameras and the motors controlling the speed of the belt must be synchronized to recognize the various packages when they run on the conveyor. As pictured in Figure 2, the speed of the main line and of the other two lines must be continuously adjusted depending on the number of packages detected by the cameras.  
With two lines (Line 1 and Line 2) active at the same time, the capacity of the main line may be overloaded. In this case, one of the secondary lines must be adjusted or stopped and then restarted. Without this synchronization, the scenario described is difficult to manage: creating a packet scheduler between desynchronized devices can introduce problems in the management of the line. In our deployment, this goal is achieved by using \"smart\" cameras and motors connected by TSN. As stated in Section 3.2, PTP--the protocol employed by the  
Figure 1: PTP hierarchy. The clock symbol specifies which nodes are synchronized with each other using PTP.  
TSN stack to obtain time synchronization--is strictly dependent on a well-defined clock hierarchy. This hierarchy is usually decided using the intrinsic capabilities of the clocks (e.g., the precision or the mean skew) and can be reconfigured by Basyx, transparently to users and administrators. Orchestration can be used to select subsets of devices, creating \"isles\" of synchronization. This can be useful in the example of the cameras explained before: a camera can be isolated from the others, synchronizing just with its subset of neighbors. This flexibility is required when one of the belts must be repaired, where the shut-down operation for maintenance will isolate the other line and make it the only belt feeding the main one. In that case, the cameras and the motors must be synchronized only between the active devices of the system. The operator can remove the inactive line from PTP synchronization and operate on it.  
As described in Section 3, the AAS provides a common structure for representing the information and behavior of an asset, while OPC UA is a communication protocol that enables secure and reliable data exchange. By using the AAS and OPC UA together, it is possible to support various IIoT applications such as condition monitoring, predictive maintenance, and asset optimization. For instance, an AAS can be used to represent the digital twin of a camera, while OPC UA can be used to collect real-time data from the camera, independently from its model and type. These data gathered through OPC UA can be then processed to obtain information about the condition of the production line in order to predict when maintenance is required. Additionally, the combination of AAS and OPC UA can facilitate the integration of other systems and devices, such as control systems and supervisory systems, allowing for a more comprehensive view of the asset.