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Wind Calibration Davis

Discussion specific to Davis weather stations
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William Grimsley
Posts: 833
Joined: Thu 22 Sep 2011 5:22 pm
Weather Station: Davis Vantage Vue
Operating System: Windows 7 Home Premium 64-bit
Location: Latitude: 50.70189285 Longitude: -3.30849957
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Wind Calibration Davis

Post by William Grimsley »

Hi there,

I am just wondering if I have calibrated my wind by accident in the console. Was this possible to do and if so how do I change it back to normal again?

Thanks,

William
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SpaceWalker
Posts: 67
Joined: Sun 04 Mar 2012 2:54 am
Weather Station: Davis Vantage
Operating System: Windows XP
Location: Eastern-Canada
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Re: Wind Calibration Davis

Post by SpaceWalker »

William, really, how do you expect any members of these forums to know if you have or have not properly calibrated the wind sensor of your weather station!

William, you might want to do some reading and have a look at the Vantage Vue Console Manual - you might get more information as to which sensor can (or cannot) be calibrated and how the sensor can (or should) be calibrated.

And please, do not quote this message!
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William Grimsley
Posts: 833
Joined: Thu 22 Sep 2011 5:22 pm
Weather Station: Davis Vantage Vue
Operating System: Windows 7 Home Premium 64-bit
Location: Latitude: 50.70189285 Longitude: -3.30849957
Contact:

Re: Wind Calibration Davis

Post by William Grimsley »

I was not asking if they knew I had, I was asking on how I did it if I had done it.

I've looked in the manual already.
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William Grimsley
Posts: 833
Joined: Thu 22 Sep 2011 5:22 pm
Weather Station: Davis Vantage Vue
Operating System: Windows 7 Home Premium 64-bit
Location: Latitude: 50.70189285 Longitude: -3.30849957
Contact:

Re: Wind Calibration Davis

Post by William Grimsley »

No, nothing in the manual. Oh well.
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andrew_sinclair
Posts: 85
Joined: Thu 04 Nov 2010 8:15 pm
Weather Station: Davis VP2 Plus c/w DFARS
Operating System: Debian version: 12 (bookworm)
Location: Cheddar, Somerset
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Re: Wind Calibration Davis

Post by andrew_sinclair »

Hello William

Thinking aloud here...Assuming that you mean wind speed and not wind direction then, since there is no user calibration functionality mentioned in the manual, my engineering thought train would be to understand how the sensor works and experiment a little.

Each time the buckets turns one full rotation a pulse is sent from the sensor. In the case of the Davis 7911 for every 1 mph there should be 26.67 revolutions per minute, 1600 revolutions per hour.

Given that then I would get hold of an occilloscope and simple measure the pulses and work out the windspeed then reconcile that with what you are seeing on your console, if they reconcile (within the measurement uncertainty of +/-5% or +/- 2mph) then all is well.

Another way of doing this without a scope would be to apply a wind of a known speed (e.g. 266.67 revolutions per minute) to the spindle of the anemometer then see what your sensor reads (for a 7911 this would be 10mph). You could even plot a graph of applied revolutions vs displayed wind speed and see how linear the relationship is.

This way you'll be able to answer your own question and get a deeper understanding into the bargain.

Andrew
Windy: f065d04a
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