[werk_ag]

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What are the variable resistors RV1 and RV3 for?

Thanks, Steve

Hi Steve,

In very good to know that you are happy with your new WeatherDuino weather station.
Interesting experiments...

The variable resistors RV1 and RV2 / RV3 are used to set the gain of the two channels of the OP IC5.

- RV1 sets the gain of the channel used for Solar Radiation. If you are using our Photovoltaic Cell, its value should be set to around 2.7K (may be fine tuned).

- RV2 / RV3 are used for the UV channel. We only have tested the system with the UVM-30A UV sensor, but it should work with any sensor with a linear response between output voltage and the UV Index. In any case, the maximum output voltage of the sensor should not exceed than 1.1V.
UVM-30A UV sensor set RV2 to 10K and RV3 to 0 (Zero or as near as possible). Purpose is having a gain = 1, when using the UVM-30A UV sensor.

If you have access to a little piece of Fused Silica glass try it, I think its the best material to use as cover for the kind of UV sensors we are talking about (covering the Photovoltaic Cell with Fused Silica glass also doesn't have any negative impact on the readings).

Rgs.