Vaisala AWS330 - Manual (Page 69)

Chapter 4 _______________________________________________________________ Installation
VAISALA _______________________________________________________________________ 67
WARNING Using a long cable between different units (sensors, transmitters, power
supplies, and displays) can cause a lethal surge voltage if a lightning
strike occurs in the vicinity. Always apply proper grounding procedures
and follow the requirements of the local Electrical Code.
Aligning Ultrasonic Wind Sensor WMT703
WMT703 is permanently marked with the letter N and a north arrow.
WMT703 needs to be aligned in such a way that this arrow points to the
north. Misaligning WMT703 causes a wind direction offset error in the
measurement results, as shown in Figure 30 on page 68.
To align WMT703, proceed as follows:
1. Determine whether the array of WMT703 is correctly aligned with
a compass or other similar method.
2. If the alignment is not correct, readjust the orientation: rotate the
FIX70 mounting kit so that the north arrow and the north
transducer point to the north in the measurement location. Do not
remove WMT703 from the mounting kit during the alignment
process. Tighten the bolts of the FIX70 mounting kit.
Figure 29 below and Figure 30 on page 68 show the correct alignment
and the measurement error caused by misalignment of WMT703.
0208-025
Figure 29 Correctly Aligned WMT703