Calibration and adjustments improvements in solar irradiance sensorsAfter months research and work, we have developed a photovoltaic reference cell dedicated to calibration and sent it to FRAUNHOFER CalLab (an internationally accredited ilac-MRA laboratory for PV cells and PV modules). The reference photovoltaic cell has undergone a two-stage process, allowing us to reduce our measure of uncertainty down to 1.3% A Reference PV cell calibrated with this level of accuracy stands out as it greatly reduces uncertainty during adjustment operations. On the market, usually, a standard PV Cell pyranometer is adjusted with an uncertainty much greater than 1.3%! By September 2015 the calibration of other manufacturer sensor’s will be done by using that reference PV cell.
Glossary of metrology termsUncertainty is a mathematical term for margin of error in a measurement. It is expressed as a range of values that enclose the true value. Typical denotation is:
Uncertainty = measured value ± uncertaintyAccuracy of a measurement system is the degree of closeness of measured values to the true value. Calibration is the operation that, under specified conditions, in a first step, establishes a relation between the quantity values with measurement uncertainties provided by measurement standards and corresponding indications with associated measurement uncertainties and, in a second step, uses this information to establish a relation for obtaining a measurement result from an indication. (JCGM 200:2008 International vocabulary of metrology) Adjustment ia the set of operations carried out on a measuring system so that it provides prescribed indications corresponding to given values of a quantity to be measured. (JCGM 200:2008 International vocabulary of metrology)