Polling-based protocol converter for the integration of hybrid wired/wireless industrial control networks

The integration of hybrid wired/wireless networks was addressed, which includes PROFIBUS, MODBUS/TCP and polling-based MAC protocol:WICN for wireless subnet. After analyzing three integration models, shared-data polling method used in the protocol converter is proposed to replace the conventional frame forwarding method. Data control management with map-data and convert-data information is built additionally to make the data exchange between different segments in a demanded time-deadline, with more flexibilities. Then the time performance of hybrid networks and converter is evaluated through five-experiments. Especially, Control-cycle-time was defined to present the time delay of data information which transferred from sensor to controller, then to actuator. The results demonstrate one Control-cycle-time is lower than 90ms and fulfill the time requirement in process industrial control application.