The purpose of this communication is to show an additional advantage of the well known guide for start and stop modes, GEMMA, that should motivate its use as well as to introduce the consideration of the human operator as an integral part of the automation procedure. The inclusion of the human operator as well as his interplay with the automation device needs some guidelines that can be drawn from joining the GEMMA structured approach and some concepts borrowed from cognitive ergonomic theory and human-computer interaction. Finally, this paper shows some examples of humanmachine interfaces (industrial panel, interface display screen).