Good morning
I got the same problem. I have a weather file with POA as input, but SAM are not decomposing this data to DHI and DNI. My POA data is from a pyranometer, so I'm checking the checkbox "POA from pyranometer".
I've read the solution on github, but I didn't get where I have to change in my weather file? I tried to set to zero values under 200, it didn't work. I did the same thing to time steps with low sun angles, but also didn't work. As result I get a negative energy production. I say change something in the weather file because I used the file "phoenix_az_fake_poa" from github issue #610 and it worked, but to mine ("FVT.-5.249.-37.974.RMY.00M_SAM_1hr") it doesn't. Feel comfortable to simulate with those files. The system's sizing is indifferent.
Could you help me?
Best regards