OPC UA integration for field devices

In industrial automation systems, deploying the well-established automation pyramid model is best practice. However, the trend to massively distributed systems, which are foreseen to co-operate using standardized protocols and common semantics, shows the limits of these traditional approaches. In order to enable for Industry 4.0 compliant solutions, appropriate means for scalable internetworking have to be developed and utilized. New modelling technologies have been developed to represent such distributed automation systems, incorporating a multidimensional layered approach. At higher hierarchy levels of these automation models, standardization approaches are quite common. However, at the field layer there are still many different field busses, which in most cases do not allow common semantics, but come along with their own object models. In contrast, the use of OPC UA at the field level, with its standardized protocol stack and semantic annotations, would allow for enabling field devives to fully participate in large scaled systems as Industry 4.0 components. This paper evaluates the potentials and limits of integrating OPC UA into legacy field devices with limited communication and calculation resources and provides quantitative measurement results of selected test scenarios.