Today’s production plants are not conceivable without automation systems. Due to the increasing complexity of production plants and therefore of automation systems, delays and interruptions in automation projects are observed. A design model for more efficient planning of industrial automation systems is introduced. It is based on a new and practical proceeding for the construction of a requirements model. Extended feature models as formal requirements representation enable to verify the consistency of requirements. New insights on the necessary capabilities of a formal reasoning system for planning the whole automation system are deduced from the design model.