Vaisala WINDCAP WMT700 Series, User Manual

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Figure 15 Example of Wind Direction Averaging
3.3.2 Wind Direction Coasting
Accurate wind direction measurement requires that the wind speed is sufficient. If you
enable wind direction coasting, WMT700 does not calculate wind direction when the wind
speed drops below the selected wind direction coasting threshold. The last calculated
direction output remains until the wind speed increases enough to reach the threshold and
WMT700 returns to normal operation.
3.3.3 Vector Averaging
When you select vector averaging, WMT700 calculates wind speed and direction averages
by adding up each x velocity and y velocity measurement from the averaging time and then
dividing the sum by the number of measurements. WMT700 converts the resultant average
x velocity and average y velocity to polar direction and magnitude, which returns the wind
direction average in degrees and wind speed average in the chosen units.
If the data acquisition system requests data before the initial averaging time completes, the
sensor returns the most recent complete measurement data.
Chapter 3 – Functional Description
37