Sampling Rate and Data Quality Issues: Experiments from Ginseng Industrial Deployment
Industrial plants such as oil refineries typically use wired sensor systems to monitor and control the production processes. As the deployment and maintenance of such cabled systems are expensive, it is desirable to replace or augment these systems using wireless technology. Wireless sensor networks (WSNs) are deployed to sense, monitor and act on the environment. Especially in industrial sense and react scenarios that require fairly fast sampling rates, minimum losses and minimum latency on messages. Considering that a few sensors may share a common sink, sharing part of their path on the way to the sink may result in undesirable message losses and delays. Our research focuses on planning a WSN to avoid excess traffic during sensing and acting to guarantee the minimal delay for critical scenarios, such as industrial applications and closed-loop control applications. In this paper we report on our experience with both a simple plan for adapting a WSN for high-rate sampling objectives and with experimental tests. Simple theoretical results let us know whether a network plan will be able to handle data processing as required. With this first-cut plan we can then test the performance of the network and if necessary reconfigure it. Basic data quality issues are also taken into account. Different characteristics can be chosen depending on application needs, resulting in reconfiguration of network parameters (number of nodes, network partitions or reduction of the sampling rate or application of filters to the data). We report on the experimental results in a test bed and industrial environment.