[werk_ag]

628 was the max reading today. The "theoretical max" was 644. So pretty close!

Yeah, any adjustment should be very small. A difference of 16 W/m2 at full noon is minimal.
Step by step you are getting a very interesting system, equipped with very good weather instruments, and the best of all: you are knowing how each of them works.

[danner]

Looking to the graphs in your webpages, seems you are getting a very close match with the theoretical values. Always make sure the pyranometer is perfectly horizontally levelled. There is small trick I read somewhere at the Apooge website. According to that trick, the side where the cable comes out of the unit, should be facing north, they say that doing it improves the readings.

It came with the leveling plate and built-in bubble level, and the cable is pointing directly north. So far I am happy with it.

My neighbor has an outside light that comes on at night. The owners manual suggests pointing a light source at the SP-110 to test it. Could that be the source of the readings I was getting last night after the sun went down? Either way it seems editing the code took care of the spurious readings at night.

[danner]

SP-110 on the mast over my roof with the Inspeed instruments.



Wind vane bracket is facing true north and that's the direction the SP-110 cable is pointing.

[werk_ag]

It came with the leveling plate and built-in bubble level, and the cable is pointing directly north. So far I am happy with it.

The levelling plate its very useful part of the equipment.

My neighbor has an outside light that comes on at night. The owners manual suggests pointing a light source at the SP-110 to test it. Could that be the source of the readings I was getting last night after the sun went down? Either way it seems editing the code took care of the spurious readings at night.

When I tested the SP-110, I never got readings spurious at night. As you saw, originally I haven't included any code to discard readings bellow a determined threshold for the SP-110. I can't say if the spurious readings are caused by your neighbour light, it can be, but also can be by other reasons.

[danner]

OK, I'll keep an eye on it tonight as the sun goes down.

Last night after the sun went below the horizon the reading dropped to 0, and then increased a few points. Then for the next few hours the reading fluctuated a few points up from 0.

If there is a problem with this sensor the guy said he would exchange it, if he doesn't sell them all before I figure out if there is a problem or not.

[werk_ag]

OK, I'll keep an eye on it tonight as the sun goes down.

Last night after the sun went below the horizon the reading dropped to 0, and then increased a few points. Then for the next few hours the reading fluctuated a few points up from 0.

If there is a problem with this sensor the guy said he would exchange it, if he doesn't sell them all before I figure out if there is a problem or not.

The sensor seems to be quite good, those spurious reads at night surely are not caused by the sensor.
They can be also happens due to a presence of a very small voltage at the ADC0 input, 1 or 2 mV are enough.
If I was you I did not worry much about it. The filtering you are using is effective and doesn't affect the overall readings, it just cause that readings start at 4 to 6 W/m2

[danner]

The sensor seems to be quite good, those spurious reads at night surely are not caused by the sensor.
They can be also happens due to a presence of a very small voltage at the ADC0 input, 1 or 2 mV are enough.

I used two twisted pairs between the TX board and the solar/uv board. ADC0 is twisted with Vcc, and ADC1 is twisted with Gnd. Should I separate them and twist ADC0 with ADC1 and Vcc with Gnd?

Wires are just long enough to reach and no longer. Looks like this. I didn't bring my side cutters with me on the roof and I was racing in-between rain showers so I didn't trim the leads of the SP-110. LOL I'll trim them the next time I go up there.

[danner]

OK the same thing happened tonight as last night, it kept reading sunlight even though the sun was down. It was stuck on 12 w/m2 and wouldn't come down. Stars were bright in the sky but it was still measuring sunlight so I edited the code to clip it at 13.

Unless suggested otherwise I am going to see if rewiring it, and twisting ADC0 to ADC1 and Vcc to Gnd, will make it behave any different.

And does anyone know why the Evapotranspiration isn't reading anything on Cumulus MX?

[werk_ag]

The wires you are using are short enough to not need to be twisted at all. Maybe it's better not do it.
A reading of 12w/m2 in the dark is to high. If possible try to measure the voltage output of the SP-110 in the dark, it should be zero (testing things before having them installed its easier, however I know that sometimes isn't possible). Even with a 0V input, can happen that the output voltage of the OP drifts from 0 to 3 mV, but will never reach a value of 7mV (which is needed to produce a reading of 12W/m2).

Just by curiosity, how are you powering the transmitter? Battery, regulated wall adapter, wall adapter with a transformer?

And does anyone know why the Evapotranspiration isn't reading anything on Cumulus MX?

Simply it isn't calculated.
If you find a way to calculate it with an Arduino, without consuming a lot of memory, please let me know, I will be very happy to include it.
The WeatherDuino Pro2 emulates the Davis communication protocol, and some aspects of a Davis weather station like the data logger, but it isn't a Davis Weather Station.

[danner]

Wires switched. Now ADC0 and ADC1 are paired and Vcc and Gnd are paired.

Edited the code from:

Code:

#if (Solar_Sensor == 2)      // Apogee SP-110: Self-Powered Pyranometer (Solar / UV interface R2= 4700 Ohm)
        if (RX_Data[2] <= 13) RX_Data[2] = 0;
        SolarRad = map(RX_Data[2], 0, 1023, 0, 1600);              // Using OP - Formula outputs an integer, between 0 and 1750 W/m2
        //SolarRad = round(((RX_data[3] * (1100 / 1024.0)) * 5);   // Not using OP. Sensor connected directly to ADC input
      #endif

To:

Code:

#if (Solar_Sensor == 2)      // Apogee SP-110: Self-Powered Pyranometer (Solar / UV interface R2= 4700 Ohm)
        if (RX_Data[2] <= 0) RX_Data[2] = 0;
        SolarRad = map(RX_Data[2], 0, 1023, 0, 1600);              // Using OP - Formula outputs an integer, between 0 and 1750 W/m2
        //SolarRad = round(((RX_data[3] * (1100 / 1024.0)) * 5);   // Not using OP. Sensor connected directly to ADC input
      #endif

And so far no fluctuations in the readings. Last night it continuously varied from 0 up to 3, back to 0, up to 6 sometimes. That can be seen on last nights Cumulus MX graph before I added the line to clip anything below 6.

Of course I also forgot to stop Cumulus MX before I yanked the sensor connector off the TX board. Now I have to edit all the ini files and logs to delete the solar readings at 10pm at night, LOL. Oh well.