Module with user entered specified specs

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Module with user entered specified specs

I've created a new project with SAM to validate my SAM SDK integration.

On SAM, I'm using PV - Flat Plate technology, a custom weather file, the "SMA America: SC500CP-US 270V" inverter, and user specified parameters for the module.

Results from SAM and the SDK are close, but different. If I choose a Module from the database then the results match! So the problem is with the Module with User Specs.

I triple checked the parameters looking at the SDK Tool and the results just don't match.

I'm only using the pvsamv1 module of the SDK to do this and am setting the values for the module like this:

cellTech = 1;
vmp = 30.0f;
imp = 6.0f;
voc = 37.0f;
isc = 7.0f;
bvoc = -0.11f;
aisc = 0.004f;
gpmp = -0.41f;
nser = 60;
area = 1.3f;
tnoct = 46.0f;
standoff = 6;
mounting = 0;

and then:

data.SetNumber("module_model", 2);

data.SetNumber("6par_celltech", cellTech);
data.SetNumber("6par_vmp", vmp);
data.SetNumber("6par_imp", imp);
data.SetNumber("6par_voc", voc);
data.SetNumber("6par_isc", isc);
data.SetNumber("6par_bvoc", bvoc);
data.SetNumber("6par_aisc", aisc);
data.SetNumber("6par_gpmp", gpmp);
data.SetNumber("6par_nser", nser);
data.SetNumber("6par_area", area);
data.SetNumber("6par_tnoct", tnoct);
data.SetNumber("6par_standoff", standoff);
data.SetNumber("6par_mounting", mounting);

Am I doing something wrong here? The parameters are the default ones for SAM when you choose "CEC - Module With User Entered Specifications"


Paul Gilman


It's hard to tell what might be causing the difference without seeing all of your code.

There is a quick way to compare SAM results with results via the SSC API. Each time you run a simulation in SAM, it creates a set of scripts in each of the languages supported by the SDK (LK, C#, MATLAB, Python, and Java). In Windows, those files are stored in the following temporary system folder C:\Users\[username]\.SAM\ssc. You can use those scripts to start building your own models, or to do the kind of comparison you are doing.

I compared results from the pvsamv1 module with SAM as follows:

  1. Open SAM, create a Flat Plate PV - Utility IPP case and run a simulation.
  2. Go to C:\Users\[username]\.SAM\ssc, open the file in a text editor, and copy its contents to clipboard (Ctrl-A, Ctrl-C).
  3. Start the SSC SDKtool, and click Script Editor.
  4. Paste the script from the text file to SDKtool (Ctrl-V).
  5. Add the line run('pvsamv1'); to the end of the script.
  6. Run the script and click Data Container.
  7. Check annual_ac_net to show the total annual AC output. The value should match the Annual Energy vaue in SAM.

Best regards,


Wow, thanks that is really useful information that I will definitely use in the future.

Now the results match, but what I did was restart SAM, I can't explain what happened. Just saved and loaded the SAM project.

Thanks for the support, I appreciate the quick answer and info.


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