Exception handling for PLC-based process control software

This paper deals with the possibility of introducing exception handling mec hanisms into the specification and code of industrial process control softw are. Although exception handling is a very important aspect of process cont rol applications, in most cases it is treated in an ad hoc and unstructured manner - which is mainly caused by the lack of appropriate constructs in p rogramming languages for programmable logic controllers. A high degree of m astery of the development process can be achieved by applying an engineerin g process based upon life cycle and domain engineering concepts. The main r esult of domain engineering is a conceptual model of the domain in question . One of the elements of the conceptual model is the specification language with a defined exception handling construct. The exception handling constr uct is illustrated by a real application excerpt. It would be useful to inc lude this exception handling construct into the Structured Text controller programming language. (C) 2000 Elsevier Science B.V. All rights reserved.