Communication interface specification in OPC UA

Due to its modeling capabilities, platform independence, and extendability, Open Platform Communications Unified Architecture (OPC UA) is considered to be the main candidate for a so-called enabling technology for industry 4.0. However, the engineering effort for OPC UA applications, in particular the server, is very high as the process of information modeling and linking the resulting model to real-world data is complex and time-consuming. This significantly limits the spread of OPC UA in manufacturing and other domains. This paper presents an approach towards extending OPC UA in a way such that information necessary for the OPC UA server application to access the underlying system can be specified in the information model. This is achieved by defining communication interfaces for all nodes of the information model that represent readable or writable data. The handling of the interfaces needs to be implemented in code only once and from then on they can be modeled, rather than implemented for each node individually. Thus, the implementation effort of OPC UA servers is reduced. Different modeling approaches for communication interfaces are presented and compared.