Fieldbus networks, as a part of distributed control applications, are subjected to harsh environment that may cause different faulty conditions. This is more pronounced in the case of hybrid wired/wireless networks because of the high susceptibility of wireless communication to such environment. PROFIBUS as one of the widely applied fieldbus protocols is considered here. Consequently, a timing analysis for hybrid wired/wireless PROFIBUS networks under a bounded error model is proposed. In this context, two alternatives for Hybrid Wired/Wireless - Multiple Logical Rings (MLR) - are discussed on the base of a single PROFIBUS network — the Single Logical Ring (SLR) - analysis. This work is essential to assess the real-time behaviour of such a PROFIBUS network under the incidence of errors.