1 Copyright © 2011 by ASME Proceedings of the International Mechanical Engineering Congress & Exposition ASME 2011 November 11-17, 2011, Denver, Colorado, USA IMECE2011-64235 A SUPPORT TOOL FOR TEACHING GRAFCET: ENGINEERING STUDENTS’ PERCEPTIONS Celina P. Leão Department of Production and Systems Engineering School, University of Minho, Guimarães, Portugal Filomena O. Soares Department of Industrial Electronics, Engineering School, University of Minho, Guimarães, Portugal José Machado Mechanical Engineering Department/CT2M Research Centre, Engineering School, University of Minho, Guimarães, Portugal P.B. de Moura Oliveira Department of Engineering, Science and Technology School, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal J. Boaventura Cunha Department of Engineering, Science and Technology School, University of Trás-os-Montes and Alto Douro, Vila Real, Portugal ABSTRACT Modeling discrete event systems with sequential behavior can be a very hard and complex task. Some formalisms are used in this context, such as: Petri Nets, Statecharts, Finite automata, Grafcet and others. Among these, Grafcet seems to be a good choice because it is easy: to learn, to understand and to use. Teaching Grafcet is then relevant within engineering courses concerned with Industrial Automation. A virtual laboratory, e-GRAFCET, developed and first tested in UTAD University; it is a new, easy-to-use multimedia e-educational tool to support the self-learning process of Grafcet. This paper, reports a study of e-GRAFCET use by the students of University of Minho. A questionnaire was prepared and students asked to fulfill it in a volunteer basis. The results were statistically analyzed and the scores compared. The overall objective is to understand how the tool helps students in their study, and consequently improve their learning off Grafcet, independently of their engineering background. INTRODUCTION Modeling discrete event systems with sequential behavior is a main subject related with Automation and Mechatronics fields. Grafcet (IEC, 2000) is a formalism which presents some advantages over other methods, such as Petri Nets (David and Alla, 1992), Statecharts (Harel, 1987), Timed Automata (Mealy, 1955), (Moore, 1956) among others. Indeed it is easy to use and understand, due to its graphical formalism with syntax and semantics well defined. Moreover, it has been the main inspiration of a major PLC (Programmable Logic Controllers) standardized languages (IEC, 1998) named as SFC (Sequential Function Chart). Sometimes, Grafcet from IEC 60848 and SFC from IEC 61131-3 are mixed and confused as being the same. However, in reality they comprise quite different concepts: the first is a specification formalism and the second is a PLC programming language, although the idea behind the first one led to the development of the second one. Teaching Automation concepts, particularly in modeling discrete sequential systems, Grafcet is widely used due to its simplicity to produce programs when PLCs allow direct use of SFC programming. Indeed, some PLC manufacturers incorporate SFC as a programming language. As mentioned previously, SFC programming language has been inspired on Grafcet formalism proposed by French Association for Economical and Technical Cybernetics (AFCET) in 1977 (IEC, 2000). Grafcet is a specification formalism for the functional description used to describe the deterministic behavior of the sequential part of an automated system (Matias et al., 2010). Teaching Grafcet is relevant within engineering courses concerned with Industrial Automation. That is the case of Mechanical and Industrial Electronics Engineering courses and their related programs. The Bologna declaration changed the teaching model followed within Universities courses. The current education system requires students to play a more active role within the teaching/learning process (Leão et al., 2007). Following this trend, using multimedia technologies together with classical teaching methodologies constitutes a great improvement in the