IEC 60891:2009 defines procedures to be followed for temperature and irradiance corrections to the measured I-V (current-voltage) characteristics of photovoltaic devices. It also defines the procedures used to determine factors relevant for these corrections. Requirements for I-V measurement of photovoltaic devices are laid down in IEC 60904-1. The main technical changes with regard the previous edition are as follows: - extends edition 1 translation procedure to irradiance change during I-V measurement; - adds 2 new translation procedures; - revises procedure for determination of temperature coefficients to include PV modules; - defines new procedure for determination of internal series resistance; - defines new procedure for determination of curve correction factor.