Calibration of pyranometer at The National Laboratory

Purpose

The national laboratories are responsible for maintaining the national reference standards for each measurement quantity and  spreading metrological competens and traceability to industry and society at large. The national reference standards are the highest level of traceability in Sweden. 

A calibration performed at a national laboratory fullfils all typical traceability and accreditation requirements that commonly exist in industry and society at large. 

Method

The calibration is performed indoors against a Hg(Xe)-lamp in comparison with a reference pyranometer. The method requires that the device under test and the reference match each other in make and model as closely as possible which puts some restraints on which types of pyranometers the method can be applied to. For example, photo diode pyranometers cannot be calibrated with this method. The calibration is performed at 500 W/m². The calibration can be performed year round. 

A calibration can also be performed directly against the sun as a source in compariton with a reference pyrheliometer. This method does not have the same restrictions on matching models. It does require a sunny and cloudless day during a time of year when the sun is high enough in the sky. 

Deliveries

The calibration results are reported in a digital calibration certificate in Swedish or English which states that the calibration was performed at a national laboratory.