06-02-2016, 12:28
Hi,
Strange, I thought I'd posted a reply yesterday, but it appears to have "vanished". However, I was only confirming that I'd be looking for a "mechanical" issue. Since the fall looks to be close to 50% it could well be one (of 2) or 2 (of 4) of the PV panel diodes becoming "short-circuit" due to overheating.
@ Werk_AG: Sorry, I din't notice your text and link before.
I'm certainly not disputing that the sensor is optimised for "Ultra-Violet", just that without a UVA-blocking filter, it cannot produce a genuine "UV-Index", which is very heavily biassed (by up to 3 orders of magnitude) towards passing (only) the UVB wavelengths.
I'm not sure of the OP's definition of "Cloudy all day", but the UV curve looks almost unchanged compared with the clear day!
Cheers, Alan.
Strange, I thought I'd posted a reply yesterday, but it appears to have "vanished". However, I was only confirming that I'd be looking for a "mechanical" issue. Since the fall looks to be close to 50% it could well be one (of 2) or 2 (of 4) of the PV panel diodes becoming "short-circuit" due to overheating.
(04-02-2016, 20:53)Werk_AG Wrote: Regarding this matter, the following text in from the manufacturer of the UV sensor used in the UVM-30A module. ...
@ Werk_AG: Sorry, I din't notice your text and link before.
I'm certainly not disputing that the sensor is optimised for "Ultra-Violet", just that without a UVA-blocking filter, it cannot produce a genuine "UV-Index", which is very heavily biassed (by up to 3 orders of magnitude) towards passing (only) the UVB wavelengths.
I'm not sure of the OP's definition of "Cloudy all day", but the UV curve looks almost unchanged compared with the clear day!
Cheers, Alan.