User`s guide

Chapter 2 __________________________________________________________ Product Overview
VAISALA_______________________________________________________________________ 51
Wind Vanes
Introduction to Wind Vane
WAV151 is a counter-balanced, low-threshold optoelectronic wind
vane. Infrared LEDs and phototransistors are mounted on six orbits on
each side of a 6-bit GRAY-coded disc. Rotated by the vane, the disc
creates changes in the code received by the phototransistors. The code
is changed in steps of 5.6°, one bit at a time to eliminate any ambiguities
in the coding.
0204-044
Figure 41 WAV151 Wind Vane
A heating element in the shaft tunnel keeps the temperature of the
bearings above the freezing level in cold climates. Nominally, it
provides 10 W of heating power. It is recommended to use a thermostat
switch in the sensor cross arm for switching the heating power on below
+4 °C.
The following numbers refer to Figure 41 on page 51:
1 = Vane assembly
2 = Sensor shaft
3 = Lower body