Exception handling for PLC-based process control software

Abstract This paper deals with the possibility of introducing exception handling mechanisms into the specification and code of industrial process control software. Although exception handling is a very important aspect of process control 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 programming languages for programmable logic controllers. A high degree of mastery of the development process can be achieved by applying an engineering process based upon life cycle and domain engineering concepts. The main result 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 construct is illustrated by a real application excerpt. It would be useful to include this exception handling construct into the Structured Text controller programming language.