Davis wind vane, wind direction offset

Davis wind vane, wind direction offset - Printable Version

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Davis wind vane, wind direction offset - Sun_Dancer - 17-08-2023

Hello WeatherDuino community,

I have a Davis 6410 wind vane, I can't align it to the north. also the wind vane cannot be unscrewed from the shaft. In the software of the TX Pro2 transmitter unit there is the possibility to set an offset for the wind direction.
I assume WDir_offs = 0 means the arm of the anemometer is pointing north. I need to install the southbound arm.
Do I then simply subtract 180 degrees from WDir_offs = 0, for example, i.e. WDir_offs = -180?

Greetings

RE: Davis wind vane, wind direction offset - werk_ag - 19-08-2023

Hi,

Since the wind vane need to be able to catch wind from any direction, why you can't align it to the North? Seems you can align it to South. Just trying to understand.
You can try using the WDir_offs as you said, but test it before installing the wind vane outside, I'm not sure it it fully work for your case.

Rgs.

RE: Davis wind vane, wind direction offset - Sun_Dancer - 19-08-2023

Good evening,

if I align the arm of the anemometer to the north, the sensor hangs in the lee of a balcony. Unfortunately, I no longer live "at the top" where the anemometer was free in all directions.
So I wanted the arm to point south.

Best regards

RE: Davis wind vane, wind direction offset - catliNZ - 26-08-2023

(19-08-2023, 19:08)Sun_Dancer Wrote: Good evening,

if I align the arm of the anemometer to the north, the sensor hangs in the lee of a balcony. Unfortunately, I no longer live "at the top" where the anemometer was free in all directions.
So I wanted the arm to point south.

Best regards

Does not sound like your readings will be that accurate from some directions.
I would suggest just changing the "wind directions names" text in the /data/lang directory to suit your situation.

RE: Davis wind vane, wind direction offset - werk_ag - 29-08-2023

Sorry to say but your suggestion isn't a solution for the Sun Dancer issue.
The wind direction is stored in the data logger and reported to Cumulus as a number, so Cumulus or any other weather software still reports the real wind direction. Also any Wireless display units he may have also will show the real direction.

RE: Davis wind vane, wind direction offset - catliNZ - 29-08-2023

Well in that case
Edit the tx software file Process_IDx.ino about line 187

Code:
// calc the current wind direction

    wind_dir = ((vane_reading - Min_vane_reading) *  360L) / (Max_vane_reading - Min_vane_reading);

    wind_dir += WDir_offs;

//addition to turn compass 180 degrees

    wind_dir += 180;

    if (wind_dir > 360)    wind_dir -= 360;

//end of addition

    // Precaution in case the calib values are wrong or slightly off

    if (wind_dir > 360)    wind_dir = 360;

    else if (wind_dir < 0) wind_dir = 0;

    wind_dir = wind_dir * 10;

    return wind_dir;

  }

#endif

#endif  // End ID2

the 180 of course can be changed to get your angle correct.
cheers, Ian

RE: Davis wind vane, wind direction offset - Sun_Dancer - 30-08-2023

Good morning,
it just sounds like it, or just reads like that. I attach great importance to the most accurate values possible for all my sensors. But the wind is such a thing, it can come from all directions at the same time and vary in strength, so the readings on the left are not less accurate than those on the right.

I have already said goodbye to the idea of correcting the wind vane by offset. Either I find the screws in the wind vane and wind wheel where they should be, because moving the wind vane on the shaft is legitimate and is also suggested by Davis, or I find another solution.

Greetings