Hi, I bought an anemometer (your #1733) from Digikey. Because it is being
used to monitor the wind speed approaching
an experimental vertical axis wind turbine, it is vital that the calibration
be 'right on'. So I thought I'd better check it. Moving the sensor through
still air at between 0 and 14 m/s, the slope of the voltage versus speed
line (ie the sensitivity) is .0313 V per m/s. This is only 63% of the
sensitivity which is implied by the 1.6 volt swing on 32.4 m/s that is
quoted on sheet 1 of the data sheet. Interestingly, it is within about 2% of
the sensitivity which would be implied using 50 m/s, which is the number
which is mentioned on sheet 2 of the data sheet. Have you had any other
questions about the 32.4 m/s? Put another way, has the manufacturer
specifically stated whether the sensitivity is 1.6/32.4 =.0494 V per m/s or
1.6/50 = .0320 V per m/s? Thank you.
anemometer calibration
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- sj_remington
- Posts: 1021
- Joined: Mon Jul 27, 2020 4:51 pm
Re: anemometer calibration
I wouldn't worry to much about the specifics in the data sheet or product page.
If you can experimentally calibrate the sensor under controlled conditions similar to the use case, and verify the calibration using an accurate, preferably certified anemometer, you're finished with that step. Keep in mind that a linear calibration curve may not be the best choice.
If you can experimentally calibrate the sensor under controlled conditions similar to the use case, and verify the calibration using an accurate, preferably certified anemometer, you're finished with that step. Keep in mind that a linear calibration curve may not be the best choice.
- jps2000
- Posts: 811
- Joined: Fri Jun 02, 2017 4:12 pm
Re: anemometer calibration
You may use a car to calibrate it. (calm day of course)
- wtx1
- Posts: 4
- Joined: Tue Jan 11, 2022 10:50 pm
Re: anemometer calibration
Thank you, yes, that is what I did. On a mast, which put the anemometer 2m above top of car. Wasn't dead calm. Steady breeze approx 1.5 m/s. Did a large number of passes upwind and downwind to zero this out.
- sj_remington
- Posts: 1021
- Joined: Mon Jul 27, 2020 4:51 pm
Re: anemometer calibration
Do you trust the car's speedometer?
Hopefully you mounted the anemometer on a mast for that test. The air velocity near the surface of a moving object is not uniform and in general, not the same as the speed of the object.
Hopefully you mounted the anemometer on a mast for that test. The air velocity near the surface of a moving object is not uniform and in general, not the same as the speed of the object.
- wtx1
- Posts: 4
- Joined: Tue Jan 11, 2022 10:50 pm
Re: anemometer calibration
Great points.
Yes, the speedometer has been checked using GPS.
And also the anemometer was mounted on a mast well above the roof of the car.
Wishing for a wind tunnel ha ha.
Yes, the speedometer has been checked using GPS.
And also the anemometer was mounted on a mast well above the roof of the car.
Wishing for a wind tunnel ha ha.
Please be positive and constructive with your questions and comments.