The development of control programs is a complex task that needs to be systematised and automated in order to reduce costs. It is demonstrated within the software engineering discipline that the use of analysis and modelling methodologies helps to reduce the software costs by systematising its development. Several methodologies have been designed to analyse and model batch and real-time systems, but not discrete event sequential systems (DESS). This paper demonstrates that the DESS control programs development process can benefit, as batch and real-time systems do, From the improvements in the software engineering, by designing a new object-oriented methodology adapted to the DESS peculiarities.