Reflection-based Prototyping Framework for OPC UA Servers for Companion Specifications

Domain-specific Companion Specifications (CS) define OPC UA information models for specific use cases, devices, or industries and define how to use OPC UA in specific environments. A sample OPC UA server is required to evaluate an OPC UA CS and develop clients. Such a server needs to be easily changed on updates of the CS and must ensure that all instances comply with the specified OPC UA types. This paper introduces an OPC UA server prototyping framework that maps OPC UA instances to $\mathbf{C++}$ data types using reflection. Using OPC UA types for instantiation, all created instances comply with the CS. The mapping to $\mathbf{C++}$ data structures provides a simplified API for handling sample instances by enabling users with limited knowledge about OPC UA to build CS-conformant servers. Four use cases show the usefulness of the approach: OPC UA Events, OPC UA PubSub and creating CS compliant servers.