APPLICATION OF DISCRETE AUTOMATA MODELS AT PROGRAMMING OF PROGRAMMABLE LOGIC CONTROLLERS

Abstract

The application of digital technologies in the modern industry is due to the introduction of programmable logic controllers, personal and industrial computers at all levels of automated control systems. A significant number of management tasks in these systems are described by models of discrete automata, on the basis of which algorithms and programs for digital control are developed. The article deals with the procedure of developing programs for programmable logic controllers on the basis of models belonging to the class of discrete event dynamic systems (DEDS). These systems are characterized by the discreteness of the space of states. Typically, Petri Networks and their extensions are used to design systems using the DEDS model. Despite its versatility of the model, created on the basis of this methodology in the study of parallel processes have a complex implementation. Instead, the use of nondeterministic automata (NA) makes it possible to investigate the location of an automaton in several local states when activating multiple transitions. An improved structure of non-deterministic automata in the form of a hierarchical model with a modular structure makes it quite easy to create programs for programmable logic controllers using the IEC 61131-3. The base module of HMNA is implemented on the basis of LD and FBD. It should be noted that in the case of modeling a discrete machine using graphs or Petri Networks, the direct use of IEC 61131-3 languages is rather problematic, so the structure of the DEDS design tool system based on the HMNA is proposed. This approach can be considered promising as it allows specialists with basic programming skills to develop digital control software for implementing complex algorithms. A training and research stand was created for students of the Department of Technical Cybernetics of KNTU and conducting research in the field of discrete automata. The stand consists of a PLC OWEN63, a PC and a control object model. PLC63 controller programming is carried out in the CODESYS environment using languages IEC 61131-3.