HD 2013.2 – Rain detector
The HD2013.2 is a rain detector based on the capacity principle. The capacity value of the sensitive element, on an alumina rest, changes according to the surface dampened by raindrops. An integrated heater keeps it dry, evaporates water and prevents false signals caused by fog or dew. The heater also activates at low temperatures, melting the snow and allowing to detect snow precipitations. The instrument external circular dome acts as a windshield for the sensor, preventing false indications.
The instrument is equipped with three different outputs: a “Rain ON/OFF” output, which detects whether it is raining/snowing (ON) or not (OFF), also used to control a relay coil or similar devices; a 0…1V voltage analogue output (calibrated) and a 1,5…6KHz frequency output(not calibrated), which provide an accurate indication of current precipitation intensity. The ON/OFF output comes with a delay circuit that indicates the”rain over” condition with a 2 minute delay, so that the “rain over” condition is distinguished from the “light rain” one. The heater can be disabled when power consumption is critical. To do it, set the Heater OFF input on 0 V. If requested when ordering, a bird spike, consisting of a 6-spike ring (spikeheight: 60mm, diameter: 3 mm), can be mounted.
The rain detector can be used either as a separate device, or connected to a datalogger system (for example: in a weather station). In figure 1, the HD2013.2 ON/OFF output is connected to a relay coil that powers an engine: should it rain, the ON/OFF output will energize the relay coil, which will close the normally open contact (in this case the rain detector is employed as part of a control system, such as, for example, for closing windows). Warning: when the HD2013.2 isconnected to a relay coil, use always a protection diode, as shown in figure 1.
Installation and Maintenance
Place the detector far from buildings, trees, etc…, taking care that no objectis over the detector, as it might prevent rain detection. Use the supplied accessories to mount the instrument; the bracket can be fixed to a pole having a diameter from 30 to 50 mm; the pole can be either horizontal or vertical thanks to the bracket double drilling. A standard 5-m cable is supplied for the electrical connection with an IP68 connector to be inserted at the bottom of the instrument: the colours of the leads and the relating functions are to befound in the technical specifications. To ensure good immunity from noises, it is recommended to connect the cable braid to the earth and to keep the heater and the electronics earth leads separate. Keep the sensor clean.