Using WSN Technology for Industrial Monitoring: a Real Case M. Franceschinis 1 , M. A. Spirito 1 , R. Tomasi 1 , G. Ossini 2 , M. Pidalà 2 1 Istituto Superiore Mario Boella (ISMB), Torino, Italy; 2 Urmet TLC, Torino, Italy 1 {surname}@ismb.it 2 {name.surname}@urmet.it Abstract This paper describes a real experience of industrial monitoring realized with WSN technology. By adopting Telos platforms, we built a WSN in which a gateway node collects monitoring data coming from some probe nodes. We present our TinyOS design developed to realize the application and to meet its requirements. The implementation of a reliable radio communication protocol and the integration of an external probe with a Telos node have been the most challenging activities. Numerous trials have been conducted to successfully verify the long-term application stability when a few probe nodes are involved. A brief discussion on a possible extension solution in order to cope with a large number of nodes is provided too. 1. Introduction Originally developed for military purposes, Wireless Sensor Network (WSN) technology [1], [2] has been applied in several civil application fields in the last decade. WSNs exhibit a number of desirable features that have contributed to their success: they integrate low-cost devices, energy consumption is extremely reduced thanks to low-power elements (i.e., the radio chip and the micro-controller) and network nodes have self-organizing and self-healing capabilities. When dealing with industrial applications, the opportunity of cable replacement is highly rated. By providing the interesting capability of logically connecting devices without any physical contact, wireless technologies remove a source of additional costs and problems. First, no communication wires means smaller equipment costs and negligible installation costs. Then, any risk of incidental cable cuttings, along with the related need for personnel intervention to re-establish the physical link, is avoided. Last, the absence of cables is particularly useful in hazardous environments, where the presence of connectors could generate micro-sparkles causing bursts or fires. This paper presents a successful experimentation of WSN technology in the field of industrial monitoring. The paper is organized as follows. Section 2 introduces the application and discusses the set of requirements that have to be met. The next two sections deal with the proposed solution: Section 3 describes the general system architecture while Section 4 focuses on TinyOS design. Section 5 provides some test results proving the system long-term stability. Finally, Section 6 briefly discusses how to extend the application when a large number of nodes is involved. 2. Application and system requirements The goal of the system is to continuously keep under control the electric status of n system critical points distributed in a region. As it is typical for industrial applications, the monitored area might be characterized by harsh propagation conditions due to the presence of electromagnetic fields and electric devices. However, the area extension is limited such that the maximum distance between any two points is smaller than the one-hop radio coverage of a low- power wireless communication technology. A stream of data represented by current intensities and voltages denotes the electric status characterizing each of the n points and is captured by a probe sampling the electric circuit at a frequency of f s =1Hz. A probe is equipped with a micro-processor, storage resources in the order of some kilobytes and a port enabling the serial communication with an external radio module. The joint device, probe and radio module, is in-line powered. The system can operate in two different modes: standard operating conditions and exceptional operating conditions. In the following we characterize them and describe how the system is requested to work in the two alternative situations. The Second International Conference on Sensor Technologies and Applications 978-0-7695-3330-8/08 $25.00 © 2008 IEEE DOI 10.1109/SENSORCOMM.2008.123 289 The Second International Conference on Sensor Technologies and Applications 978-0-7695-3330-8/08 $25.00 © 2008 IEEE DOI 10.1109/SENSORCOMM.2008.123 282