Documenting and Comparing OPC UA Information Models

Since its release as an IEC standard series, the OPC Unified Architecture (OPC UA) has become a widely adopted platform for both vertical and horizontal communications as well as data exchange in cyber-physical systems (CPS). A key benefit of OPC UA is its extensible object model, which offers the possibility to define custom information models, which may represent a specific production domain. As these generally represent interfaces for other applications, comprehensible documentation is an essential requirement in most cases.In this paper, we describe an approach to document, maintain and compare versions of OPC UA information models generated from existing code artifacts in the domain of serial machinery engineering. Base for the contribution of this work is the prototype of a documentation and model comparison tool (NodeDoc). We will describe its usage context and requirements as well as its main features. In addition, we discuss encountered challenges and provide insights into proposed solutions along with relevant lessons learned during the development of NodeDoc.