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Please, proceed carefully following the tips published in this blog, specially when Main Power is involved. I'm not responsible for any damages caused by what is written in this blog.
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Tuesday, 8 March 2016

Data acquisition - Photovoltaic production




Another kind of data I would like to acquire is the production of my photovoltaic plant, a 3 kwp plant built over my roof and made by SUNAGE 250 swiss modules and AROS SIRIO inverter.

I also received a little energy monitor tool, which allows me to verify power production through a wireless display. This display is able to store data in a little sqlite database. Through a USB connection, it lets me view and download data using a PC.

This tool is called OWL

http://www.theowl.com/energy-monitors/standalone-monitors/owl-usb/


My model is the OWL+USB CM160.

The OWL has a little bug because it also detects reactive power when the inverter is switched off (during the night for example...)

For my purpose I have to connect OWL to Raspberry. Unfortunately this is not supported and there aren't official drivers. Making some research over the internet, I found a good linux open source interface for OWL: EAGLE-OWL https://github.com/cornetp/eagle-owl

I compiled and installed this software directly into the Raspberry. It is a background process which detects the CM160 e gets the database data.

This is the shell of Raspberry where you can see the eagle-owl software and database files.


This process will run automatically on startup. Then I wrote a little php script which is able to read CM160 database file e put its data into mysql. In this way I could store all historical data which will be displayed through a web interface.

This script will run on Raspberry every minute (standard cron task).