The accuracy of the power measurement is set by the quality and reliability of the sun simulator.
The IEC Standard IEC 60904-9 classifies sun simulators in three classes:
A (the best), B and C depending on three parameters:
IEC 60904-9 Class A SunSim 3c
Non-uniformity of irradiance ≤ 2 % ≤ 1.0 %
Pulse instability (long term) ≤ 2 % ≤ 1.0 %
Spectral irradiance distribution ≤ ± 25 % ≤ ± 12.5 %
This means that the SunSim 3c could be rated class AA AA AA (or A+ according to TÜV). This outstanding quality is the result of Pasans more than 25 years of experience and technical expertise in the field of PV measurements. Therefore manufacturers who want to improve their ROI (Return on Investment) and to price their modules with the highest precision rely on Pasan equipments, as do most of the prestigious institutes and certification bodies worldwide. According to your module dimensions, you can choose between different module testers.