A Systematic Approach to OPC UA Information Model Design

Current trends in manufacturing focus on the use of Information and Communication Technologies (ICT). The physical world and its virtual representation are increasingly converging, which leads to Cyber-Physical Production Systems (CPPS) in the manufacturing environment. CPPS synergize conventional production technology as well as ICT, allowing machines and products to exchange information, trigger actions and control other components autonomously. Therefore, seamless communication between physical objects of the shop floor and various computer systems is required. The Reference Architecture Model Industrie 4.0 (RAMI4.0) provided by the Plattform Industrie 4.0 specifies requirements for CPPS consisting of Industrie 4.0-components. In such systems, a major goal is to enable communication of I4.0 components among each other via industrial networks. For this purpose, RAMI4.0 suggests that each component has a virtual representation and uses Service-Oriented Architecture (SOA) based communication with I4.0-semantics. This paper describes a systematic approach to OPC Unified Architecture (OPC UA) information model for representing the static and dynamic behavior of manufacturing systems. Moreover, the approach is generic in the sense that it can be used to define information models for multiple target technologies, such as OPC UA, MTConnect and others. It even allows to reuse large parts of the generated models for similar manufacturing utilities and various target technologies. Therefore, we first present a concept for system analysis and design by using the Unified Modeling Language (UML), which is widely accepted for interdisciplinary work. The information gathered is then transformed to OPC UA information models which serves as target technology in this paper. The purpose of this approach is to simplify the process of defining virtual representations of manufacturing systems. Applying the presented concept allows transformation of classic manufacturing systems into CPPS with SOA-based communication and semantically rich virtual representations of individual components. It is therefore well suited to meet the requirements specified by RAMI4.0.