Wind Speed Sensor 2740/2740EX0 pages

Wind Speed Sensor 2740/2740EX
A sensor for measuring the average and
maximum wind speed (gust) during the
sampling interval. The sensor is designed for
use with Aanderaa Dataloggers 3634/3660
and the Aanderaa Automatic Weather Station
2700.
Features:
•tLow power
•tLow threshold speed
•tHigh maximum speed
•tUser friendly
•tSR10 output format

Datalogger 3660

The Wind Speed Sensor 2740 consists of a three cup
rotor on top of an aluminium housing. The sensor
can be fitted directly onto the Sensor Cross Arms
3415/3435 of an AADI Automatic Weather Station
or used separately if a connecting cable is used. The
sensor foot will fit onto a 25 mm vertical tube.
The rotor bearing assembly consist of two stainless
steel ball bearings in an assembly protected by a
surrounding skirt. The lower end of the skirt is
furnished with a magnet, and the magnet’s rotation is
sensed by a magneto inductive switch located inside
the housing.
A micro controller reads the pulses from the magneto
inductive switch sensing the rotors rotation and use
the pulse count to calculate the wind speed. The
sensor has two output signals; average wind speed
and maximum wind speed (gust) during the sampling
interval.

The average wind speed is obtained as the arithmetic
mean of the wind regardless of the sampling interval,
provided that the sampling interval is between four
seconds and three hours.
The maximum wind speed is the highest speed occurring
over a two second period at any time during the
sampling interval.
The micro controller also provides the AADI SR10
output signals for wind speed and gust. Both output
signals will have the same conversion factor for
calculation of wind speed in engineering units from
the ten bit output data. This factor is independent of
the sampling interval used.
From august 1998 the sensor has been supplied with
a new and more rugged three cup rotor designated
2228A.

D151 - Nov 2012