Gill Instruments Ltd
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MaxiMet
Page 6
Issue 1
Doc. No. 1957-PS-000x
March 2015
Wind Speed and Direction Sensor (GMX200 and GMX600)
The MaxiMet uses the Gill WindSonic wind speed and direction sensor. The WindSonic measures
the times taken for an ultrasonic pulse of sound to travel from the North (N) transducer to the
South (S) transducer, and compares it with the time for a pulse to travel from S to N transducer.
Likewise times are compared between West (W) and East (E), and E and W transducer.
If, for example, a North wind is blowing, then the time taken for the pulse to travel from N to S will
be faster than from S to N, whereas the W to E, and E to W times will be the same. The wind
speed and direction can then be calculated from the differences in the times of flight on each axis.
This calculation is independent of factors such as temperature.
Compass points
The compass point and polarity of U and V if the wind components along the U and V axis are
blowing in the direction of the respective arrows.
MaxiMet can output the following wind readings depending on use of the Compass.
Relative wind – wind speed and/or direction, uncorrected, but relative to the north marker, which
may not be facing North).
Corrected wind – with the aid of the Compass Magnetic North corrected wind direction can be
output.
North
Alignment
Pointers
S
N
W
E
