Hi,
I don't know anything about that specific radiometer and the additional information that you've posted today, but:
The calibration certificate says that the solar sensor delivers 12.71 mV at 1000 watts/m2, which doesn't seem too far from the nominal specification of 14mV. I don't know what input level werk_ has used for the input calibration, but I see the "full scale" is (about) 1.1 volts and his maximum expected insolation is around 1400 Watts/m2. So I guess the required input level for 1000 W/m2 is about 700 mV. If you want to use the actual calibration of your sensor (assuming its calibration is still acurate after 15 years) then you will need to know (or be able to set) the exact value.
So basically you need to amplify the signal by about 700 / 12.71 , or around 55. If you are using a circuit as shown in post #52 here, then if the pot R3 is set to the top of its track (or better replaced by a 47k fixed resistor) then pot R4 needs to be set to about 850 ohms (takiing into account the 18 ohms source resistance). So a 1k or 2k2 pot might be better, or ideally an 820 ohm fixed resistor if you are able to use a calibration factor in the WeatherDuino software.
Of course the optimum calibration range will depend on your location (very different peak light levels between UK and Australia) and I don't know how accurate/stable is the "1.1 volt" reference in the Arduino.
Cheers, Alan.
I don't know anything about that specific radiometer and the additional information that you've posted today, but:
The calibration certificate says that the solar sensor delivers 12.71 mV at 1000 watts/m2, which doesn't seem too far from the nominal specification of 14mV. I don't know what input level werk_ has used for the input calibration, but I see the "full scale" is (about) 1.1 volts and his maximum expected insolation is around 1400 Watts/m2. So I guess the required input level for 1000 W/m2 is about 700 mV. If you want to use the actual calibration of your sensor (assuming its calibration is still acurate after 15 years) then you will need to know (or be able to set) the exact value.
So basically you need to amplify the signal by about 700 / 12.71 , or around 55. If you are using a circuit as shown in post #52 here, then if the pot R3 is set to the top of its track (or better replaced by a 47k fixed resistor) then pot R4 needs to be set to about 850 ohms (takiing into account the 18 ohms source resistance). So a 1k or 2k2 pot might be better, or ideally an 820 ohm fixed resistor if you are able to use a calibration factor in the WeatherDuino software.
Of course the optimum calibration range will depend on your location (very different peak light levels between UK and Australia) and I don't know how accurate/stable is the "1.1 volt" reference in the Arduino.
Cheers, Alan.