# When Operation Technology Meets Information Technology: Challenges and Opportunities
## 3 State of the Art in I4.0
### BaSyx  
The BaSyx platform [32] is the result of the project BaSys 4.0 ([[https://www.basys40.de/](https://www.basys40.de/)]([https://www.basys40.de/](https://www.basys40.de/)), accessed on 29 December 2022), which is funded by the German Federal Ministry of Education and Research. The main benefits of employing BaSyx are as follows:  
* **End-to-end digitization**: Realized by providing logic communication objects to all connected devices through the Virtual Automation Bus (VAB), which bridges communication networks by mapping well-defined network operations to network-specific primitives [33]. * **Changeable production**: Changes in automation processes require developers to adapt Programmable Logic Controller (PLC) programs and require testing of all changes. In addition, every problem that occurs delays the restart of a production line, and is therefore highly expensive. The service-oriented architecture of BaSys, which encapsulates PLC programs as reusable services, acts as an enabler to realize changeable production [16]. As a result, a change in the production process is not reflected by a change in the PLC programs. Thus, architecture changes in production processes can be virtually tested, reducing downtime to a minimum. * **Integrating live process data from assets**: Digital twins are complete digital representations of physical assets; therefore, they must reflect the current state of an asset. Eclipse BaSyx connects digital twins to real-world assets with data provider components that communicate through a variety of IoT and IIoT protocols, such as OPC UA, MQTT, and HTTP/REST. * **Unified interfaces to assets**: Digital twins need to integrate different kinds of assets. Eclipse BaSyx implements bidirectional digital twins, i.e., a digital twin that both represents the current state of an asset and realizes a unified interface to that asset. Eclipse BaSyx uses the Asset Administration Shell ([[https://wiki.eclipse.org/BaSyx_/_Documentation_/_AssetAdministrationShell](https://wiki.eclipse.org/BaSyx_/_Documentation_/_AssetAdministrationShell)]([https://wiki.eclipse.org/BaSyx_/_Documentation_/_AssetAdministrationShell](https://wiki.eclipse.org/BaSyx_/_Documentation_/_AssetAdministrationShell)), accessed on 29 December 2022) (AAS) as the base technology for digital twins. Asset Administration Shells are one main component of Industry 4.0 for providing information exploit abstraction between higher levels and lower ones, hiding the complexity of the assets and creating an interface between the physical and virtual production steps. The AAS is a standardized data model and architecture for the representation and management of industrial assets. It is designed to enable interoperability and data exchange between different automation systems and devices in the industrial Internet of Things (IIoT). The AAS is the digital representation of an asset, where an asset can be anything valuable to an organization--such as a physical device, software component, worker, or product--but also includes the manufacturing process. Each AAS is identified by a unique identifier and composed of a header and a body: the former contains identifying details regarding the asset administration shell and the represented asset, while the latter comprises a certain number of submodels--both static or dynamic--that provide asset-specific information [34]. Static submodels contain data--e.g., describing offered services and how to reach them--and the physical properties of the represented asset. A static model, for example, describes an OPC UA server that provides live sensor data or access to device control functions. Dynamic submodels contain instead dynamic data, e.g., live-measured sensor data. A dynamic model also may offer callable services; thus, it can provide direct access to manage or even control assets. Asset Administration Shells must be registered in the Eclipse BaSyx AAS registry [35].