Methodology for developing programmes to implement in programmable logic controllers (PLCs). MEPUS

The aim of this paper is to present a methodology for the development of the user program to which we have called MEPUS (Methodology for Structuring the User Program by Jumping, in Spanish). This methodology eliminates the randomness of programming, while considerably the time of the reading cycle or scan, especially in the sequential processes. Furthermore, it is independent of the design method used to represent the secuencialization model of the process to automate, be it Petri net, Grafcet, Binodal Theory, etc. It is not a new method of design of scheduled automations. It is a graphical tool for the drafting of the user program. Also, and even it is a minor advantage, the PLC's internal resources are optimized (timers, counters, etc.), as this methodology allows them to be reused in the same program. Based on the results obtained during more than 10 years, it is concluded that this new methodology the user program is obtained more easily, especially way clear and systematic, which facilitates learning by the learner. For this work we have chosen as model of secuentialization of the process to automate the Grafcet, because it is the most used by PLC programmers.