Weather Station Operation/Installation Manual
Operation of the
Weather Station
Wind Speed
The wind speed measurement portion of the Weather Station consists of three ultrasonic transducers spaced equally around a horizontally- aligned circle.
The wind speed is measured by measuring the time of flight of an ultrasonic sound pulse, generated by one sensor and received by the other two sensors. Each of the three sensors takes a turn at being the transmitter, while the remaining two sensors receive the pulse.
Wind blowing in the direction of flight of a pulse increases the speed of the pulse by the amount of the wind speed. Measuring the time of flight in both directions between a given pair of transducers allows the speed of sound to be cancelled out of the calculation, making the wind speed computation independent of air temperature and relative humidity.
The ultrasonic transducers are robust, yet sensitive instruments. The transducers themselves must be kept free of any coating, such as paint.
NOTICE
The Weather Station unit itself, especially the area between the transducers, must be kept clean and free of debris for maximum wind speed and direction accuracy.
A3280 Rev 1.2 |
