Last update :  10-May-2007

Pyranometer Amplifier

The described amplifier is a high sophisticated part of a solar irradiation measurement and logging project.

pyrano_amp1

(click to picture)


The most important unit of a solar radiation measurement system is a
good , trusted and calibrated radiation sensor. Such a sensor is very expensive and  hard to get  just for hobby projects. On the WEB there are some publications which deal with different sensor solutions. I checked some of these,  but finally I decided to buy a commercial  ISO9060 Seconardy Standard Pyranometer ( it hit a big dent in my hobby finances! ). But it was worth it, it works perfect.

However , a  sensor  is just "half of the trip". A Pyranometer delivers about 4 ... 14 uV/W/m. The output voltage must be converted to a  range which can easily be detected and processed. This requires an amplifier  which is able to cover the given resolution and the given voltage range (0..15mV) in a wide temperature range, with less noise, offset and drift.
Eventually I decided to use an Analog Device AD8556 Sensor Amplifier and the 12 bit A/D converter AD7992. A micro controller is needed for amplifier programming and to process the results of  the ADC.

pyranoamt
  
Maybe this helps others who are looking for similar solutions, even for non solar projects.
 
(Click to link to get it! )
 Main PCB of the measurement and logging systemSolar Irradiation Measurement System with display, power supply CF interface and 868MHz transceiver Kipp&Zonen Pyranometer CM11
 pyrano2 pyrano3 pyrano4
(click to pictures)




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