ISO 9060 pyranometer SR20

second class

SR20 is a pyranometer of the highest category in the ISO 9060 classification system: secondary standard. This solar radiation sensor is used where the highest measurement accuracy is required. It measures the solar radiation received by a plane surface from a 180o field of view angle. In order to improve overall measurement accuracy, this sensor tackles very effectively 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, while competing models state 12 W/m2 unventilated and 7 W/m2 ventilated. The temperature dependence of every individual in