Error in using customised weather files - cannot determine time step

Dear Michael,

The weather file you attached to your post has a total of 17520 rows, but only 17517 rows of weather data.

Also, SAM does not know how to interpret data that appears in Excel as blank or with "#VALUE". You can replace those values with a value like -9999 to avoid problems with SAM's weather file reader.

Best regards,
Paul.

Dear Michael,
It turns out that the names in Row 1 can be in any order, but they have to be exactly the same as the ones shown in the SAM CSV format description in Help. For your file, they should be:

Location ID,City,State,Country,Latitude,Longitude,Time Zone,Elevation,Source

 

In your file, what should have been "Location ID" was "Location," and what should have been "State" was "Region."

 

In the file you attached to your original post, I changed the Row 1 heading, and was able to run a detailed photovoltaic simulation (after adding three rows at the end to give it 17,520 data rows), even with the missing data and "#VALUE" in some of the cells.

 

One other note: I assume you are modeling a photovoltaic system because the file only has data for GHI, DNI, Tdry, and Wspd. SAM's detailed photovoltaic model will run with a weather file that does not have all three solar radiation components, but the PVWatts will not. To use your file, you'll have to tell SAM to use GHI and DNI instead of the default DNI and DHI: On the Location and Resource page under PV Albedo and Radiation (click the plus button to expand that part of the page), choose Total and Beam for the irradiance components.

 

Best regards,

Paul.