Christian Frei

Data communications standards: a case for the UML

This paper argues for the UML as a means to rigorously specify data models and communications services of industrial data communications standards. Such standards contain among others the syntactic and semantic description of the application data to be exchanged among devices and systems of different vendors. As a consequence of the growing number and complexity of types of application data and their resulting specific communications services, it becomes almost impossible to maintain specification consistency and avoid ambiguities on the basis of informal, textual notations. By means of example, this paper discusses the recently accepted IEC 61850 standard “Communications networks and systems in substations” and its shortcomings due to the lack of formal notations. It is shown how many of these shortcomings can be overcome and additional benefits provided through the use of UML models – models that could ultimately find their way into the normative parts of such standards.

Modelling and using IEC 61850-7-2 (ACSI) as an API

IEC 61850, a recently adopted standard for communications in substations, defines a large data model of the substation domain and a set of services that operate on that data. The latter is called ACSI (abstract communication system interface). It is specified in the standard in a text-and-table format. In this paper, we argue in favour of an ACSI API (application programming interface), which would largely facilitate development of software applications that need to support the IEC 61850 standard. We describe our work on the design of such an API and its usage in the development of a simple application.