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Environmental Measurements Limited |
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A range of surface wetness probes for detecting rain, frost and dew. |
Product Summary |
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These probes are essentially ‘ON’ or ‘OFF’ devices with virtually no graduation between the two modes. The sensitive part of the probe is an etched area which consists of three carbon electrodes separated by waterproof resin. It is difficult to define sensitivity; however, a droplet of distilled water 1mm in diameter will switch the sensor from "OFF" to "ON" mode, when the signal output goes from 0v to 1.0v. The Dew/Condensation probe area is ridged to increase the active area whereas the Rain Detector probe is smooth, to allow water droplets to run off more easily; mounting the probe at an angle also helps with this. The Dew/Condensation probe should be mounted at ground level, with the sensor element level near the top of the grass. A bracket is supplied for this purpose. The Rain Detector may be mounted at ground level or on the cross arm of a weather station. The Frost Detector is similar to the Rain Detector, but also includes a thermistor for monitoring the temperature. Since frost is basically dry and may not normally be detected by the dew type probe, the Frost Probe is checked by the logger monitoring the temperature and if it appears that frost is likely then the heaters are operated for a short period. Any frost present would then melt and switch the probe. |
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ORDERING INFORMATION:
SW120D Dew / Condensation Probe. SW120R Rain Detection Probe. SW120F Frost Detection Probe. SWPSU Power supply for heater models. |
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SW120 sensors |
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