Geonica - Model GEO-SD6 -Sunshine Duration Sensor

The measurements are done on the optical principle. The basic part of the sensing unit is a circular shade. There are 16 slots evenly distributed along the shade perimeter. Behind the slots, screened photosensitive elements (photo-diodes) are placed. During the assembly, the sensing unit shall be oriented so that the axis of the shade runs parallel to the rotation axis of the Earth. The orientation of the sensing unit, evenly distributed photodiodes, and a suitable size of slots in the shade ensure that solar and sky radiation is absorbed at any position of the Sun.

Solar radiation together with sky radiation falls on a glass cupola, goes through the exposed slots and falls on the photodiodes. Each photodiode is connected to the evaluation electronics of the sensing unit. By comparing the intensity of the radiation an executive programme of the detector evaluates if the radiation is scattered (i.e. the Sun is hidden in clouds, fog. etc.) or direct (over 120 W/m"). The output information is a piece of two-state information "YES - NO" (shining - not shining). The Sunshine Duration Sensor is designed for connection to our Data Logger / Transmitter model METEODATA -2000/3000, which monitors the current status of the sensing-unite-output in a given time-period. In such a way we can obtain information about the character of direct solar radiation. No part of
the sensor is mobile, which is a great advantage.