The monitoring and controlling system uses the RF Mesh network to collect the data from various devices (Turbines) and send them to the backend system via an Access Node. These RF mesh networks [9] are composed of Radio Nodes grouped around Access Nodes[9] which act as gateways over a WAN to a data center that runs a Backend System software for communications, data acquisition, handling of events, storing of data, analyzing, processing, presenting and exporting the data.
There is a 2 way communication channel between each Radio Node[9] and the Backend System implemented over the 900 MHz unlicensed ISM band. The RF network is a mesh type of network, meaning that Radio Nodes that cannot directly communicate with the Access Node make use of other available Radio Nodes to relay messages over dynamically created routes as opposed to using fixed dedicated repeaters. This eliminates the need for a repeater infrastructure when deploying the network.
The RF network protocol consists of a mesh network layer running on top of a Frequency Hopping Spread Spectrum protocol. Both line powered and battery powered devices are supported by the network. One Access Node can control up to 10,000 Radio Nodes Turbines. The general model of the network is a push model, with the devices sending data according to predefined schedules downloaded from the corresponding Access Nodes, which in turn download the schedules from the Backend System. Alarm mechanisms are also implemented, with the End Nodes being capable of generating alarm messages when a predefined event occurs. The events are like generator failure, power outages, battery low, cracks detections.