Hybrid wired/wireless implementations of Profibus DP: a feasibility study based on Ethernet and Bluetooth

The communication networks used by factory automation systems are beginning to employ solutions that, until recently, were used in different fields. In particular, at the lowest level of automation, where, typically, real time communication between controllers and sensors/actuators is required, both Ethernet and wireless networks are becoming solutions of interest. However, the introduction of such technologies poses severe problems in terms of compatibility with already implanted fieldbuses. It is thus highly likely that, in the near future, modifications of the existing fieldbus standards will be considered, in order to accommodate hybrid network configurations, where communications take place on both Ethernet/wireless segments. This paper considers a very popular fieldbus protocol, Profibus DP, and analyzes the possibility of implementing it on hybrid wired/wireless networks, based on Ethernet and Bluetooth, respectively. Two basic configurations are analyzed and, after a description of how the Profibus DP protocol functions could be mapped on both Ethernet and Bluetooth, a theoretical study of the network behavior is carried out. Finally, simulations results are shown, which validate the theoretical analysis and show the soundness of the proposed protocol stack for industrial applications. q 2004 Elsevier B.V. All rights reserved.