Transformation of GRAFCET to PLC code including hierarchical structures

GRAFCET is an advantageous modelling language for the specification of controllers in discrete event systems. It allows for hierarchically structuring a control program's specification based on the elements enclosing steps, partial-Grafcets and forcing orders. A method is already available for the automatic transformation of Grafcets1 into PLC code but this method cannot keep the hierarchical structures due to limitations of the PLC language SFC. In this contribution a systematic approach to automatically transform Grafcets into PLC code while retaining the hierarchical structures is described.