Generic OPC UA Server Framework

Piotr P Nikiel,Benjamin Farnham,Stefan Schlenker,Viatcheslav Filimonov

doi:10.1088/1742-6596/664/8/082039

Piotr P Nikiel, Benjamin Farnham + Show 2 more

Open Access

https://doi.org/10.1088/1742-6596/664/8/082039

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Abstract

This paper describes a new approach for generic design and efficient development of OPC UA servers. Development starts with creation of a design file, in XML format, describing an object-oriented information model of the target system or device. Using this model, the framework generates an executable OPC UA server application, which exposes the per-design OPC UA address space, without the developer writing a single line of code. Furthermore, the framework generates skeleton code into which the developer adds the necessary logic for integration to the target system or device.This approach allows both developers unfamiliar with the OPC UA standard, and advanced OPC UA developers, to create servers for the systems they are experts in while greatly reducing design and development effort as compared to developments based purely on COTS OPC UA toolkits. Higher level software may further benefit from the explicit OPC UA server model by using the XML design description as the basis for generating client connectivity configuration and server data representation. Moreover, having the XML design description at hand facilitates automatic generation of validation tools.In this contribution, the concept and implementation of this framework is detailed along with examples of actual production-level usage in the detector control system of the ATLAS experiment at CERN and beyond.

Highlights

Distributed control systems require middleware – software which transfers data between components of a distributed system.The ATLAS Detector Control System (DCS)[1] is an example of such a distributed control system
It is necessary to provide OPC Unified Architecture (UA) servers to numerous types of subsystems integrated into the DCS
Apart from obvious common functionality in which identical software parts were identified, it became evident that considerable saving of development efforts could be achieved if the data model of a given subsystems server was considered a parameter of a generalized OPC UA server

Summary

Introduction

Distributed control systems require middleware – software which transfers data between components of a distributed system. The ATLAS Detector Control System (DCS)[1] is an example of such a distributed control system. Being organized as a hierarchical mesh of often heterogeneous components, the middleware must be capable of handling various data models, while being portable and performant at the same time. For the ATLAS DCS, OPC Unified Architecture (UA)[2] has been selected as its new standard for middleware[3]. It is necessary to provide OPC UA servers to numerous types of subsystems integrated into the DCS. A common approach to create these OPC UA servers allows to reduce development and maintenance costs, and provides added value in reusable software components and technology

Present address

DESIGN FILE

Findings

Conclusions