SR20-D1 is a solar radiation sensor of the highest category in the ISO 9060 classification system: secondary standard. Irradiance is output digitally in W/m². SR20-D1 is designed for the solar PV industry, using the Modbus communication protocol over RS-485. Individually tested for temperature and directional response, SR20-D1 is the most accurate digital secondary standard pyranometer available. It measures the solar radiation received by a plane surface, in W/m², from a 180^o field of view angle. SR20-D1’s digital output, provided via the industry standard Modbus protocol, allows for easy data acquisition and error-free instrument exchange.

Best pyranometer for the PV industry

SR20-D1 is the most accurate digital secondary standard pyranometer available. Its benefits:

• Digital output: easy implementation & servicing
• Best-in-class temperature response, < ± 0.4 % (-30 to +50 °C), best  “zero offset a” and best calibration uncertainty
• Included in delivery as required by ISO 9060: test certificates for temperature response and directional response

In order to improve overall measurement accuracy, Hukseflux effectively targeted two major sources of measurement uncertainty: calibration and “zero offset a”.
In addition, SR20-D1 has a negligible temperature response. All are best in class. The temperature response of every individual instrument is tested and corrected onboard by the instrument electronics, using a second degree polynomial. SR20-D1’s low temperature dependence makes it the ideal candidate for use under very cold and very hot conditions.