The cycle from one release of a software product to the next is becoming shorter and shorter. Especially for custom software products (nonstandard software), implementation productivity needs to be increased. The reuse of prefabricated software components and the implementation of reusable and extensible software are of great importance. The object-oriented programming paradigm has already proven to fulfill these demands in the area of graphical user interfaces or visualization in general, but its applicability undoubtedly extends beyond user interfaces. Thus we initiated a project with the aim to examine the impact object-oriented programming can have on the design and implementation of automation software. In this paper we present a framework for process automation software which was implemented on SUN SPARC stations using ET++ (a user interface application framework) and C++. In addition to the design of the framework, we describe the implementation of a process control software for a ladle furnace (part of a steel plant) using our framework.