Hi Marvin,
Thank you for sharing that excellent article:
solarprofessional.com/articles/design-installation/simulating-nec-voltage-and-current-values?v=disable_pagination&nopaging=1
SAM reports the array's open-circuit voltage (Voc) in each time step based on the cell temperature in that time step. The cell temperature, in turn, is calculated from the incident irradiance and ambient temperature in the time step. The author's post-processing equations calculate a
worst-case value of Voc, not a more accurate value. This is similar to the macro I mentioned above, where you can enter temperature values for worst-case calculations and compare those to the operating values SAM calculates.
Best regards,
Paul.