A Petri Net formal design methodology for discrete-event control of industrial automated systems

Abstract

Increasing complexity of Industrial automated systems requires high level discrete event control implementation in programmable logic controllers (PLCs). To date most PLC applications for industrial discrete event control systems (DECS) are basically heuristic, mostly supported by partial system analysis and limited performance evaluation. Consequently the application of formal methods in PLC programming became extremely essential for industrial automation. During the past few decades Petri Nets (PN) have evolved to a very promising formal tool to establish an integrated solution for modeling, analysis, simulation and control of industrial automated systems. This paper presents a methodology for implementation of high level DECS PN models in PLCs using IEC 1131-3 standard programming languages. The produced PLC code is completely dual to its original PN model capturing completely its dynamic properties and can be fully restored directly from its PLC code. The flexibility of the PN models is reflected in the DECS's PLC code being simply and accurately updated following the changes conducted in the DECS's model. Index Terms-Petri Net (PN), Discrete Event Control System (DECS), Programmable Logic Controller (PLC).

A Program Model of Fuzzy Interpreted Petri Net to Control Discrete Event Systems

“…All of these advantages are analogical to the cited executable specifications. Moreover, there are some similar approaches to the one proposed in this work [28][29][30][31][32][33][34][35][36][37][38][39]41]. Implementation of some of them can also be seen as a programming language.…”

“…When compared to other mentioned solutions [28][29][30][31][32][33][34][35][36][37][38][39]41], the main advantage of the program model based on FIPN is the possibility of using analogue sensors for the direct control of DES. Contrary to Grafcet and SFC [28][29][30][31][32][33], FIPN allows resources modelling in the structure of a net, because the weight of arcs and the places capacity can be greater than one, while Grafcet and SFC are based on binary net.…”

“…The main advantages in comparison with FIPN are the automatic investigation of properties through application of the SIPN editor and the possibility of using modularity. Apart from the three solutions mentioned, which seem complete because of software tools, there are some others which propose the conversion of PNs to LD [34,38,39,41]. They have many advantages and they do not take into consideration only binary nets, (e.g., [34]).…”

Modelling of secondary cooling system with a distributed architecture, using Coloured Petri nets

“…A CPN is a mathematical formalism and graphical tool that enables the formal description of systems, whose dynamics are characterized by the concurrence, synchronization, mutual exclusion and conflicts, which are characteristics of a distributed PS [6,7]. Several studies that employ this approach demonstrate its effectiveness [7][8][9][10][11]. The advantage offered by the models developed with CPN compared to other types of Petri nets is the possibility of interpreting the values of the variables (temperature, presure, etc.)…”

Ladder Diagram Petri Nets: Discrete Event Systems

“…The main motive or need to model the control algorithms in LD is because they are developed mainly based on the experience of programmers in industrial control [2,3], so it is important to propose approaches that help guarantee the safe control algorithms applied in machines or industrial processes, and the theory of PN [4] allows modeling the basic control lines used in the LD algorithms. Different approaches have been presented to provide a solution to analyze, model and simulate control algorithms developed in LD with PN or vice versa [5][6][7][8][9][10][11].…”