Advances in logic controllers design

Logic controller design, typical of industrial applications may be of a complex nature. Synthesis of such system may be difficult and time consuming when using intuitive method such us ladder diagram, or rigorous but classical means based on Karnaugh maps, or Huffman method. There exists a growing need for a global approach taking account of events, states and offering systematic design. The latest developments of graphical representation suitable for sequential evolution and the increasing availability of programmable devices make it attractive to utilize them for logic controller design and consequently their education. This paper introduces an approach developed by the author in order to obtain a systematic and simple synthesis without constrains. Designers are provided a methodology and tools allowing the development of programmable logic-controller applications with low cost techniques. Function charts are utilized as graphical means for the functional description of a given controller. The graphical model obtained is transcribed into algebraic expressions. The implementation can be achieved using programmable devices or any other technology. A universal algorithm has been conceived and tested to develop controllers using this new approach. The experimental results are satisfying. An application example is given to illustrate the different steps of the synthesis method.