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Solar Radiation Readings

Posted: Fri 04 Apr 2014 3:39 pm
by yogiadobe
Hi, Can anyone help? I can't get my head round the way that my WS 3083 weather station displays the solar radiation figure as against the display in cumulus. As an example at this moment in time 4:25pm the weather is a grey cloudy day. My WS 3083 is reading 9.5 W/m2 but cumulus is reading 51 W/m2. Why is there such a huge difference in the two readings. I haven't altered any of the default settings within the cumulus station configuration settings i.e. Sun Threshold 75%, Sun min 0 W/m2, Trans Factor 0.08. Am I missing something? Please Help!

Re: Solar Radiation Readings

Posted: Fri 04 Apr 2014 3:56 pm
by steve
The sensor actually measures 'Lux' rather than W/m2. Cumulus converts the Lux value to W/m2 using the generally accepted standard factor for sunlight of 0.0079. The console appears to use some other conversion factor, and it appears that the figure that the console uses is far too low. There is some discussion about this in this thread: https://cumulus.hosiene.co.uk/viewtopic.php?f=13&t=6910

If you would prefer that Cumulus uses a different conversion factor, you can add a "LuxToWM2" entry to cumulus.ini; see the section on cumulus.ini in the wiki.

Re: Solar Radiation Readings

Posted: Fri 04 Apr 2014 4:09 pm
by yogiadobe
Thanks Steve, I will take a look at the two links that you posted. Incidently I live on the East Coast of the U.K. at around 55ft above sea level. I'm not sure if that would influence the readings. I should have mentioned this in my first post!