LX7007
pro IGC V1.0
Apr. 2005
Page 68
The angular difference between HDG and TRK depends on the magnitude of the wind vector and is normally quite
small, which means that the measurement has to be quite precise if accuracy is to be achieved. While the GPS data
(TRK and GS) is precise, small inaccuracies in the heading of about 5° can cause errors of up to 25km/h in the wind
strength. This method only works during straight flight and the calculation is stopped as soon as HDG and TAS
change rapidly as occurs when the glider is turning.
6.1.2
Installation of the compass module
The device consists of two parts, a compass sensor and electronic device. The compass sensor should be built
somewhere far from iron parts, which can cause errors in reading. Respect flight direction arrow and install the unit
horizontal. All connections are plug_and_play, so there is no mistake possible. A
485 splitting
unit to extend LX
485 bus is included. The box with electronic could be installed on the convenient place in the glider , orientation
doesn’t matter.
6.1.2.1
Where to install:
The compass module should be installed as far as possible away from magnetic, electrical and steel parts (loud
speakers and analogue vario indicators contain strong magnets). Even the mechanical compass should be as far
away from the sensor as possible. Minimum distance is 20cm. As mentioned above, the arrows should be aligned
accurately in the flight direction and parallel to the fore and aft axis of the glider. For a proper installation a plane
area parallel to the horizontal plane is needed.
6.1.2.2
First test after installation:
An external reference compass is required which can either be a prismatic landing compass or a calibrated compass
base on the airfield surface. Using the reference compass, the glider should be aligned in each of the eight main
directions (360
°
, 45
°
, 90
°
, 135
°
, 180
°
, 225
°
, 270
°
and 335
°
). Now the glider should be oriented into north direction,
while doing that watch the HDG displayed on Nav.-page 3 of the LX 7007 PRO IGC (do not try to compensate the
compass yet!). If the HDG varies more than
±
5
0
, turn the compass so, that the deviation decreases below
±
5
0
.
Now turn the aircraft into the other directions and read the displayed values (don’t change the compass position
anymore). If they vary more than
±
10
0
look for another place for the compass module.
6.1.3
Adjusting the compass module:
The compensation of the compass is made in the SETUP menu after entering the password (96990).
1. Orientate the glider again to 360
0
.
2. Set the cursor on N and press ENTER (actual HDG is displayed).
3. Press ENTER again (storing the measured value)
4. Set the cursor on 45
°
, orientate the aircraft to 45
°
and again store the measured value.
5. Repeat the procedure for the remaining directions
The compensation table will look similar to that above when you have finished the procedure. Leave the menu with
ESC.
6.1.4
Final test:
pressing ENTER