Dear All,
We are customizing our visibility sensor to be plug and play in ISS solar radiation RJ11 Port.(10~1800 meters correspond to 10-1800 W/m2), that's why we really need to reach "1800" reading.
But strange thing happen, and Davis console never show up a 1800 W/m2 reading at its solar radiation port.
I am posting here to find out if you guys notice this?
We have studied the way how ISS sample data from wind cup/ wind vane, and we successfully finished customization of Davis VP2 compatible ultrasonic anemometer last year.
In our understanding of ISS:
The wind speed signal is transmitted in pulse
and wind direction, solar radiation signals are transmitted in variable resistance(digital potentiometer) to ISS.
Three methods had been used to test if ISS/Console can recognize maximum reading of solar radiation.
Method one.
When our HY-SLV2E output 3VDC voltage, the reading of console is keep "----", we think it trigger ISS(sensor suit transmitter) limitation of detection of voltage.
After we slightly reduce the voltage as 2955 mV, we got a reading: 1782 Watt/m2
Below is our test result for your info.(the output voltage resolution of our digital to analog converter is about 0.7 mV.
Voltage below is actual voltage measured by multimeter, we tried to change various output voltage.
But we found the smallest addtion of voltage we increased based on 2955mV all led to one single result: a null display on Davis console "----"
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Below is screenshot taken from Davis solar radiation sensor manual:
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Method two.
We use a potentiometer to directly output/reflect the voltage supplied by ISS to ISS itself.
By changing its resistance, we are able to simulate a solar radiation reading to cheat the ISS.
But the reading we got from Davis console is still constrained to its maximum 1782 W/m2. (we test it both on cabled VP2 and wireless VP2)
Method three.
Davis sensor suit transmitter is considering "wind direction" and "solar radiation" sensor as potentiometer/resistance and measuring how much voltage is distributed on them from the 3VDC reference voltage.
Interesting thing happened during our test, photo attached IS for your reference to explain you what we found.
No matter how hard I tried to adjust angle of Davis wind vane purposely "wrongly" plug at Solar Port at Davis sensor suit transmitter (around 350°), the maximum reading of solar radiation I can get at console is still 1782 Watt/m2, which substantiate my previous view that console itself may not be able to recognize maximum reading of solar radiation before the upper limitation Davis programmed lead it to output a "----" state.(just like method 1,2)
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Look forward to hearing opinion from members at this forum.
Thanks.