Programmable Logic Controllers (PLCs) are currently being used to control increasingly complex processes. A new standard for PLC programming languages, IEC 1131-3, is helping to improve PLC software implementation. However, there are few widely adopted PLC software design methods. Poor software design can result in long testing and commissioning periods and costly downtime. In mainstream software engineering, object oriented analysis and design methods are becoming widely accepted. This paper reports the merging of the two technologies by showing a mapping between an object-oriented analysis and design method and its realization in accordance with IEC 1131-3. The mapping is illustrated by a Pedestrian Crossing example.
- object-oriented PLC