Integration of existing IEC 61131-3 systems in an IEC 61499 distributed solution Stefano Campanelli, Pierfrancesco Foglia, Cosimo Antonio Prete Dipartimento di Ingegneria dell'Informazione, Università di Pisa Via Diotisalvi 2, 56126 Pisa, Italy {stefano.campanelli, foglia, prete}@iet.unipi.it Abstract The IEC 61499 standard allows to model and design new generation control systems, providing innovative concepts of software engineering (such as abstraction, encapsulation, reuse) to the world of control engineering. The industrial reception of the standard, however, is still in an early stage, also because its introduction results in the adoption of a programming paradigm profoundly different than the widespread IEC 61131-3. This paper presents a method for the integration of the two standards, that allows to exploit the benefits of both. The proposed architecture is based on the parallel execution of both environments that interact with each other through some specific interfaces. A test implementation of the architecture is also presented to demonstrate the feasibility of the proposed solution. 1. Introduction Programmable Logic Controllers (PLCs) are some of the most widespread devices used in industrial automation. In 1993, the International Electrotechnical Commission (IEC) published the IEC 61131-3 standard [1] in order to define a common programming interface for PLCs produced by different manufacturers. Since then, the standard has been widely adopted among PLC producers. Evolution of computer networks brought the technology to realize control applications distributed between different devices. Distributed control is highly desirable in manufacturing industry, since it provides some benefits such as improved flexibility, reliability, maintainability and reduced wiring costs [2], however, a distributed control system is more difficult to design than a centralized system. In order to facilitate the design of distributed control systems, IEC proposed the IEC 61499 standard [3] for distributed control and automation. The standard defines an open architecture that allows to model and design control applications where control logic is decentralized in software components that can be distributed across different hardware devices connected by networks [4]. The benefits of the standard have been proven through some practical case studies [5-7] and there are some commercial tools supporting the standard (ISaGRAF [8] and NxtControl [9]) already on the market. Despite this, the industry adoption of the standard is still in an early stage [10], this is due to challenges of both technical and economic nature that must be overcome to allow the widespread diffusion of the standard. Some of the technical challenges, such as predictability and scalability, are already discussed in [11] and [4]. From an economic point of view, companies have made investments in IEC 61131-3 and their interest is to preserve their know-how and developed software [12]. In fact, since IEC 61131-3 has been in use for years, there is a large number of control systems and software libraries that are based on this standard. Unfortunately, the IEC 61499 standard is very different from IEC 61131-3 in many ways, such as execution model or data handling, so it is not possible to directly port IEC 61131-3 applications in an IEC 61499 based runtime environment. In addition, IEC 61131-3 was quickly adopted by industry because its languages were very similar to the already existing non-standard languages used by control engineers to program PLCs, so personnel and design methodologies could be easily reused. On the contrary, IEC 61499 requires a different approach to the programming of control systems that makes it necessary to train personnel for the new standard. Moreover, existing design methodologies, patterns, competences and know-how acquired for IEC 61131-3 are not directly applicable in the design of IEC 61499 systems. For the reasons specified above, it is not convenient for companies to convert existing systems to IEC 61499, nevertheless, many of these systems may take advantage from distribution of control logic to increase interoperability, reduce human work, improve control decisions, etc. The first problem addressed in this paper regards the implementation of distributed control logic on existing IEC 61131-3 systems. As it has already been said, distributed control brings benefits to manufacturing industry, however, the IEC 61131-3 focuses on programming aspects of a single device. Some communication functionalities that can be used to realize Copyright: 17th IEEE International Conference on Emerging Technologies and Factory Automation