3 Mode of Operation
Wind direction
The dynamic characteristics of the wind vane is achieved by the aluminum lightweight construction.
The co-action of wind vane and balance weight results in a high damping ratio with small delay
distance as excellent characteristic of the complete vane.
The axis of the wind vane is running in ball bearings and carries a diametrically magnetized magnet
at the inner end. The angle position of the axis is scanned contact-free by a magnetic angle sensor
(TMR-Sensor, Tunnel Magneto Resistance) through the position of the magnet field. As the sensor
is operated in magnetic saturation, effects by external magnetic fields can almost be eliminated.
The connected electronics calculates the angle position of the axis and provides the respective
serial output signal.
Acquisition of Wind Velocity
Additionally to the wind direction acquisition the wind direction transmitter offers the option of sup-
plying the wind velocity signal from the
Wind transmitter First Class 4.3351.x0.000
. The wind veloc-
ity signal is acquired and analyzed and is available in the output telegram along with the acquired
wind direction.
General
An AC- or DC-voltage of 24 V is intended for the separate supply of the optional heating. In all
probability, the heating guarantees a trouble-free function of the Wind Direction Transmitter First
Class even under extreme meteorological icing-conditions.
The outer parts of the instrument are made of corrosion-resistant anodized aluminum, and stain-
less steel. Highly effective labyrinth gaskets and O-rings protect the sensitive parts inside the in-
strument against humidity and dust.
4 Recommendation Site Selection / Standard Installation
In general wind measurement instruments should be able to detect the wind conditions of a large
area. In order to obtain comparable values when determining the surface wind, measurements
should be taken at a height of 10 meters over an even area with no obstacles. An area with no ob-
stacles means that the distance between the wind direction transmitter and an obstacle should be
at least 10 times the height of the obstacle (s. VDI 3786 Part 2). If it is not possible to fulfill this
condition then the wind direction transmitter should be set up a height where local obstacles do not
influence the measured values to any significant extent (approx. 6 - 10 m above the obstacle). The
wind direction transmitter should be set up in the center of flat roofs and not on the edge in order to
avoid any preferential directions.
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