This paper contributes to a formal framework for the automation of production systems. Automatic control systems deal currently with theoretical modelling techniques aiming to formally define the behaviour of a control system when process behaviours and system requirements are well defined. Our approach aims to facilitate a common and consensual understanding of an automated system at the early stage of a systems engineering process. This approach is based on the use UML stereotypes, based on a systemic approach, to globally formalise a production system.