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 0V.

If requested when ordering, a bird spike, consisting of a 6-spike ring (spike

height: 60mm, diameter: 3 mm), can be mounted.

Typical Applications

The rain detector can be used either as a separate device, or connected to a data

logger 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 is

connected 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 object

is over the detector, as it might prevent rain detection. Use the supplied

accessories to mount the instrument; the bracket can be fixed to a post having

a diameter from 30 to 50mm; the post 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 be

found 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. Clean the sensor regularly with a cotton

flock soaked in distilled water; in case of ingrained dirt, mild cleansers can be

used in moderation.

The sensor is fragile, as it is placed on an alumina rest, thus handle it with

care!