Enabling Industry 4.0 Communication Protocol Interoperability: An OPC UA Case Study

Rapid advances in digitalization are leading the automation and manufacturing sector towards the fourth industrial revolution also known as Industry 4.0, whose main goal is to realize the changeable production processes, which is currently expensive and effort-intensive. The Open Platform Communications Unified Architecture (OPC UA) is an established and well-known communication protocol in the industrial domain. The Reference Architecture Model Industry4.0 (RAMI 4.0) proposes OPC UA as the core communication protocol among assets such as machines, robots, and appliances. Despite the key role of OPC UA in Industry 4.0, there is still a lack of technical guidance on how to integrate OPC UA with other communication protocols, especially with legacy devices that communicate through proprietary protocols. To address this challenge, we propose a solution that is characterized by a set of communication primitives, a platform-independent type system and an intermediate language. We also evaluate the overhead created through integration in terms of the round-trip time and message size imposed by metadata for abstraction. We have implemented the proposed approach in reference Industry 4.0 projects, and in this paper, we report our experiences in integrating OPC UA in a homogeneous communication system comprised of Create, Read, Update, Delete and Invoke primitives which improves the protocol interoperability and reduces integration effort.