Operator`s manual

24
Installation, Operation and Maintainance of Buoy Operated Automatic Meteorological Stations
Sensors
3.1.2 Installation
The wind sensors should be located away from wind obstructing obstacles like trees and buildings. As a general
rule, the horizontal distance between wind set and obstruction should measure at least ten times the height of the
obstruction.
Follow the below instructions to install the Wind Set at 2 meters height and 4 meters height. Figure 7 presents a
graphic explanation of the sensor.
Attach the 2 supplied 019ALU cross arms each at 2 meters and 4 meters height on the instrument tower;•
Orient this cross arm in the east-west direction, with ¾” x 1” Nu-rail facing West on the Southern hemisphere, •
and East on the Northern hemisphere, and tighten the set screws;
Remove the plastic nut on the propeller shaft and install the propeller on the shaft so that the letter markings •
on the propeller face forward.
Mount the wind monitor to the supplied vertical 12 inches long pipe piece of 1 inches diameter and tighten the •
clamp at the base of the sensor
Place the Wind Set with the 12 inches long pipe into ¾” x 1” NU-rail of the 019ALU crossarm and tighten the •
alignment screw firmly;
Align the sensors so that the box of the wind monitor points to the true South and tighten the set screws on •
the NU-rail;
Route the sensor cable along the underside of the cross arm to the datalogger;•
Do not cut any excess cable since this may be useful at other occasions, instead tie it up carefully;•
Connect the cable to the wiring panel according to table 1 in paragraph 2.2, and Annex 2, as follows:•
Wind Speed and Direction Sensor (1) at 2 Meters:
- Black wire to terminal G
- Clear wire to terminal G
- White wire to terminal AG
- Green wire to terminal H3
- Blue wire to terminal E1
- Red wire to terminal P1
Wind Speed and Direction Sensor (2) at 4 Meters:
- Black wire to terminal G
- Clear wire to terminal G
- White wire to terminal AG
- Green wire to terminal L3
- Blue wire to terminal E1
- Red wire to terminal P2
Box 5: Determining the Geographic North
A compass is the appropriate instrument for locating the North. However, a compass determines the mag-
netic north, which differs from the geographic one. Though the location of the magnetic north is subject to
constant change, it can be considered stable for time spans in the order of magnitude of 100 years.
The magnetic declination is defined as the angle between magnetic and geographic North. It has been
determined for each spot on earth and is exactly THREE DEGREES and ZERO MINUTES West in the Lake Vic-
toria region.
To determine the geographic north, measure the magnetic north with a compass and adjust for the existing
magnetic declination by adding THREE DEGREES and ZERO MINUTES in a clock- wise direction.
While orienting the cross arm and Nu-rail using a compass, please note that there is a difference between geo-
graphic and magnetic north. Figure 9 presents the current declination angle for the Lake Victoria region.