POA from reference cell

How do I input POA from reference cell? What format does this file need to be in? If I only have 3 months of collected data from the reference cell can i create filler values and just narrow in on hourly results for which i have data?

tried this from other post, "To use POA data in your weather file, you should use the SAM CSV format, which is described in SAM's help system.

For the SAM CSV format, the columns do not have to be in a specific order because SAM identifies each column by its heading. For example, it identifies the POA column by the heading "POA." The weather file only needs to contain the data you plan to use, so for a POA file, you can omit the columns for DNI, DHI, and GHI. (The file may also contain all of the columns -- SAM will only use the columns that you specify on the Location and Resource input page.)

The SAM CSV format is a simple comma-separated format, so you can use any spreadsheet program or text editor to create or edit the files."

I followed and get this error, "exec fail(pvsamv1): could not read data line 1 in weather file while loading POA data
Simulation pvsamv1 failed."

The POA data shows in the weather file if i click on "view data..."

Hello,
SAM is designed to run with a weather file that contains a complete year's worth of data. That error message indicates that there is a problem with the weather file.
If you have POA data for only three months, you should place that data in the correct position in the weather file so that the other data in the file is appropriate. For example, if the three months are in the summer, you would want the POA data to match, at least roughly, the temperature and wind speed data.
Would you mind [url=mailto:sam.support@nrel.gov?subject=Files%20for%203%20months%20POA%20data t=_self]emailing me[/url] a copy of the weather file you created along with the .sam file you want to use it with? I can try to see what is causing the simulation error.
Best regards,

Paul.