EFITA/WCCA 2005 25-28 July 2005, Vila Real, Portugal 2005 EFITA/WCCA JOINT CONGRESS ON IT IN AGRICULTURE Application of LonWorks® Distributed Control Technology in Greenhouses Gilberto A. Pereira a , Carlos E. Cugnasca b a Agricultural Automation Laboratory, Escola Politécnica, Universidade de São Paulo, Brazil, professor.gilberto@uol.com.br b LAA, Brazil, carlos.cugnasca@poli.usp.br Abstract Greenhouses are becoming more important every day due to the requirements of modern agriculture. The market is becoming increasingly competitive, demanding better quality products at reasonable costs. Optimization of production processes inputs and environmental preservation are also important aspects that must be considered. In order to attend to these necessities it is important to improve the greenhouse control systems. Lately, there has been an increase in the use of distributed control systems that provide more flexible, scalable and cost effective solutions. This paper highlights the features of typical greenhouse automation systems and proposes a solution for greenhouse automation using the LonWorks® distributed control technology. Key words: Greenhouse, Distributed Control, Automation, Control Network, LonWorks 1 Introduction Typical commercial and industrial supervision and control systems present as main characteristics centralized architecture, and proprietary hardware and software. Manufacturer dependency, lack of flexibility, incompatible communication protocols and the need of a high performance central processor are examples of problems of this kind of solution. Nowadays, a new control system approach based on control networks and open solutions has been increasingly considered. A control network with controllers, sensors, actuators, and other devices with intelligence and communication capabilities (called nodes) implements a new supervision and control system with important advantages, such as flexibility, expandability of the control elements, standardization and implementation of complex control algorithms. Other important aspects are: optimization of costs, cabling reduction, scalability, and remote supervision and operation. LonWorks® is a technology suitable for distributed control systems. Although it is wide used scale in building automation area, other applications such as greenhouses and livestock production facilities can be attended by this technology. Created in the beginning of the 90’s by Echelon Corporation, USA (Echelon Corporation, 1999), LonWorks® is an open technology, allowing the development of interoperable devices and flexible systems. The diversity of communications media supported by LonWorks® is also very important to applications such as greenhouses. Single twisted-pair cable, power line, radio frequency (RF), and fiber optics are examples of available media. 2 Modern greenhouse automation control system characteristics The use of computers is essential in modern greenhouse control systems (Serôdio, C et al., 2001). Similarly to industrial line production, the greenhouse process must be fully controlled. However, 1349