For use where the highest measurement accuracy is required, secondary standard is the highest category in the ISO 9060 classification system
The SR20 measures the solar radiation received by a plane surface, in W/m2, from a 180 degree field of view angle. Released in February 2013 , it enables you to attain the highest measurement accuracy and excels in demanding applications.
In order to improve overall measurement accuracy, Hukseflux effectively targeted two major sources of measurement uncertainty: calibration and "zero offset a".
The initial calibration uncertainty is reduced to less than 1.2 %, an improvement of 15% relative to competing models.
The "zero offset a" specification of SR20 is 5 W/m2 unventilated. Competing models state 12 W/m2 unventilated and 7 W/m2 ventilated.
Specifications
Measurand: hemispherical solar radiation
ISO classification: secondary standard pyranometer
Calibration uncertainty: < 1.2 % (k = 2)
Zero offset a: 5 W/m2 unventilated
Calibration traceability: to WRR
Spectral range: 300 to 2800 x 10-9 m (50 % transmission points)
Sensitivity (nominal): 15 x 10-6 V/(W/m2)
Rated operating temperature: -40 to +80 oC
Standard cable length: 5 m
Temperature response: <± 1 % (-10 to +40 °C); <± 0.4 % (-30 to +50 °C) with correction in dataprocessing
