An architecture for wireless extension of PROFIBUS

Industrial communication systems and fieldbus systems can benefit in many ways from wireless LAN technology. However, the large amount of already deployed fieldbus LANs motivates to focus on wireless extensions of existing fieldbus systems, allowing to run wireless and wired stations in the same fieldbus LAN. There exist different architectural options for the coupling of wireless stations to a wired fieldbus LAN. For the PROFIBUS, a well-known and standardized fieldbus system we present and motivate a specific coupling architecture, the virtual ring extension. In this architecture the lower layer protocols of the PROFIBUS (medium access control layer and link layer) are not used on the wireless side. Instead, a set of specifically tailored protocols is used, which allows to take the error behavior of wireless channels into account, which is significantly different from that of wired channels. The key elements of this architecture are presented and some operational aspects are discussed in more detail.