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Environmental measurement & analysis
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Sunshine Duration Sensors


The WMO has defined sunshine duration as the time interval when direct solar radiation exceeds 120W/m2. There are many ways to measure or calculate sunshine duration from direct or global radiation data.

EKO can offer 3 different methods either based on direct or global radiation measurements.




  1. The most accurate method to measure sunshine duration is to use the MS-56 pyrheliometer in combination with a sun tracker STR-21G/22G.
  2. The second alternative is the MS-093 Sunshine duration sensor which is only sensitive to the direct radiation component and provides a pulse output when the irradiance exceeds 120 W/m2.
  3. Using a Pyranometer measuring global radiation. The direct radiation component can be estimated when the solar position is known.


Product Model Description
MS-093 Sunshine Duration Sensor

MS-093 Sunshine Duration Sensor

EKO Sunshine Duration Meter MS-093 has a specially designed and rotating mirror, which reflects the …


Specifications MS-093
Output 100 pulses/hour in fine weather
Directional response ±5% (within latitude ±23.5°)
Temperature dependency ±5% / °C(within -20 to +40°C)
Non-linearity ±2.5%
Threshold value 120 W/m2
Detector type Pyro electric detector (spectral response 0.3 - 2.5 µm)
Integration error less than 10 min/day (clear days)


Dimensions 350 x 250 x 200 mm (including optional base plate)
Weight 2.5 kg
Power requirements 12 VDC, 400mA


Base plate 350 x 250 mm / leveling feet
Power supply 100 ~ 240 VAC / 12 VDC / 200 x 140 x 80 mm / 2.5 kg
Heater  100 ~ 240 VAC @ 50W/ Control thermostat / heater switches < 0°C
Blower Fan 100 ~ 240 VAC @ 16W


Outdoors Material testing

Outdoors Material testing

Weathering of materials is most often an irreversible process affecting the cosmetic properties or strength of materials. This aging process is mainly driven by UV radiation, Heat, ...

Calibration & Traceability

The MS-093 Sunshine duration sensor is calibrated indoors with a 1000 W/m2 Xe light source. To set the 120 W/m2 threshold level the output of the Xe beam is precisely attenuated by a set of optical filters to a level of 120 W/m2. 

Frequently Asked Questions

Re-calibration interval of solar sensors

Re-calibration interval of solar sensors

The sensitivity of the solar sensor will slightly deviate with time when it is exposed to solar radiation. Therefore it is advised to re-calibrate the sensor every two years. For calibration ...