Cumulus Support

Hi,
I am new to this with a Ws-3081.
The UV sensor always reads high.
Is there any modification etc to reduce this reading

Hi Norman,

I've expressed my personal opinion here and here.

I have now stuck a strip of PVC tape above the UV sensor (near the lower left-hand corner of the sloping PV cell) only because I experienced a "crash" of the solar module (software) possibly/probably due to the UV level exceeding 14 (in the UK!!!). Mine is now reading "low", but as I said above "garbage in = garbage out".

For Australia (where you may get higher UV values than 10), a filter would be a better solution than scaling (which will reduce the maximum value that can be shown). I've no idea what to use as a "proper" filter since sun glasses (for example) are specifically intended to eliminate UV.

Cheers, Alan.

Hi Alan
Thanks for the info.
I might make a chart to record and compare what the UV readings are , to the official UV readings.
There might be some correletion. If not, then maybe a table to show for eg a reading of say 7 is really 2.8
Regards
Norman

Hi Norman,

Yes it would be very interesting to know if there is any correlation between the FO and official UV measurements, and also with FO's "Lux" value (both scales are linear, Lux just being about 10,000 times larger).

Of course UV and Lux should not correlate fully (if they did then there would be no point in measuring both), but they might not "correlate" even if measuring the same light frequencies (colours). FO's Lux sensor is mounted under a diffusing white dome so should "see" the whole sky, whilst the UV sensor appears to be a "flat plate collector" with a bias towards the vertical direction.

Cheers, Alan.

I made a complaint a while ago to the firm that imports these stations. (branded Alecto in Netherlands)
A few days ago I recieved a new UV/solar sensor. Apparently it has been modified. The packing slip mention "send new version" Now it seems to transmit realistic values (als compared to other stations, mainly Davis and Oregon Scientific, in the vicinity on Wunderground) Comparing the two sensors you could see that another type of sensor cell(on the lefthand side when you have the solar panel slanting towards you) has been fitted to th unit.
However, one problem was solved, and I got another one back.... Now the solar radiation readings are absolutely ridiculous. They are about 1.5 times as high as the should be acourding to the max solar radiation graph. Just before I change the sensor the values corrsponded nicely on a bright sunny day

avmourik wrote:Now the solar radiation readings are absolutely ridiculous. They are about 1.5 times as high as the should be acourding to the max solar radiation graph.

Don't forget that there are various conversion factors involved in getting from the FO Lux value to the solar radiation figure displayed by Cumulus. You may just need to do some adjusting.

steve wrote:

Don't forget that there are various conversion factors involved in getting from the FO Lux value to the solar radiation figure displayed by Cumulus. You may just need to do some adjusting.[/quote]

Thanks Steve, I am aware of that.
I didn't make any changes to the settings before and after changing the sensor. As the readings on the station do not correspond with the maximum values for my location, it's my opinion that the problem has got to do with the sensor or the station. I wouldn't be surprised if there is a problem with the displayunit combined with the modified sensor.