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SOFTWARE

Pyranometer Responsivity INTERpolator (PRINTER)

The Pyranometer Responsivity INTERpolator (PRINTER) interpolates pyranometer incidence angle dependent calibration factors, or responsivities (µV/W/m2), into an accurate and easy to use single polynomial function. The polynomials can be of very low or high degree, are extrapolated to 0° and 90°, and are calculated using robust techniques to avoid oscillations and overshoots, which can occur when using other regression methods.

The program input is a text file in the format of a Broadband Outdoor Radiometer CALibration (BORCAL) file. The program outputs are plots of the responsivities and associated uncertainties and coefficients for the polynomial regression fits of both the responsivities and the upper prediction interval of the associated standard uncertainties. These calculated coefficients for the single polynomial functions can then be easily copied and implemented in spreadsheet software or a programming environment.

Sample Spreadsheet: Coeff Template.xlsm

Related Publications

Methodology and Calculator for High Precision Regression Fits of Pyranometer Angular Responsivities and the Associated Uncertainties

Organizations

System/Platform Requirements

PRINTER runs on Windows computers, and needs the MATLAB Runtime, R2013a (8.1), 32-bit.

Licensing Information

This tool was produced by the National Institute of Standards and Technology (NIST), an agency of the U.S. government, and pursuant to Title 17 Section 105 of the United States Code this software is not subject to copyright protection and is in the public domain.

Names of companies and products, and links to commercial pages are provided in order to adequately specify procedures and equipment used. In no case does such identification imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the products are necessarily the best available for the purpose.

We would appreciate acknowledgement if the software is used.

Download Information

Download PRINTER
Download the MATLAB Runtime, R2013a (8.1), 32-bit (needed to run program)
Download the PRINTER MATLAB source code (needs Curve Fitting and Statistics Toolboxes)
Download the sample calibration data file (needs Microsoft Excel)

Documentation/User Guide

Install the MATLAB Runtime, R2013a (8.1), 32-bit; a download link is above.
Open PRINTER and select a calibration data file in the NREL BORCAL format; a sample file download link is above.
Choose whether to average (recommended) or keep separate the AM and PM responsivities.
Adjust the various regression parameters to achieve the desired fit.
Press Copy Table for later pasting the coefficients into a spreadsheet or Copy as CSV for later pasting into a programming environment. See the sample spreadsheet in the above download link for examples on how to implement the coefficients.

Created July 29, 2015, Updated September 21, 2016