Operation Guide 2891
9
Digital Compass Reference
❚
What is a digital compass?
The Earth is like a giant magnet with a north pole and a south
pole. The magnetism of the Earth is called “terrestrial magnetism”.
The magnetic sensor of your watch is a magnetic compass that
detects terrestrial magnetism to determine direction.
Earth
❚
Magnetic compass north reading
The northerly direction detected by a magnetic compass is
“magnetic north,” which is different from “true north”. Depending
on your location on the globe, the magnetic north indicated on a
compass is actually east or west of true north. The angle that is
formed by the difference between magnetic north and true north is
called the “declination”.
The magnetic north pole is located north of Canada, while the
magnetic south pole is located south of Australia. In Japan, the
declination angle is 5 degrees (around Kagoshima) to about 9
degrees (around Hokkaido) west.
Magnetic north pole
Magnetic south pole
Precautions During Calibration
•
When performing 2-point
calibration, perform calibration of
the first point and the second
point in the same location.
•
Keep as far away from possible from the vehicle’s equipment,
body, and other possible sources of magnetism.
•
Depending on the condition of the magnetism of the vehicle,
proper direction readings may not be possible.
•
Magnetism differs from vehicle to vehicle. Be sure to perform
2-point calibration whenever you change from one vehicle to
another.
•
You should also perform 2-point calibration again if you change
position (from the driver’s seat to the back seat, etc.) within the
same vehicle.
❚
Using the Compass in an Automobile
The entire body of a vehicle may be magnetized, which will make
proper direction readings impossible. By performing 2-point
calibration, however, you can use the compass to take
approximate readings while riding in an automobile.
•
See “To perform 2-point calibration” for information about how to
perform 2-point calibration.
Important!
Never try to perform 2-point calibration while driving.
Doing so is very dangerous and creates the risk of
serious accident.
1.
First, park the vehicle in a
safe area where you can
turn it around 180 degrees.
2.
At a location inside the
vehicle that is away from
its equipment and body,
use the 2-point calibration
screen to calibrate the first
point.
3.
Turn the vehicle around 180 degrees, and then calibrate the
second point.
❚
The watch shows different direction
readings at the same location.
Cause:
Unstable magnetism caused by high-voltage lines
nearby.
Remedy:
Change to a different location and try again.
❚
Correct direction readings are not
possible indoors.
Cause:
A nearby TV, computer, or other device is disturbing the
directionality of the magnetism.
Remedy:
Change to another location or move outside and try
again. Note that correct direction readings are not
possible inside of a ferro-concrete structure.
Digital Compass Troubleshooting
Proper direction readings will not be possible in areas exposed to unstable magnetism or areas where something is interfering with
terrestrial magnetism.
Also note that accurate direction readings are not possible if you do not perform the required operations correctly. Check the following
points if you suspect that direction readings are wrong for some reason.
❚
The displayed direction is wrong.
Cause 1:
You did not perform 2-point calibration.
Remedy:
Correctly perform 2-point calibration.
Cause 2:
There is source of strong magnetism nearby.
Remedy:
If any of the following objects are nearby, move away
and try taking a direction reading again.
Electrical equipment, large bridge, structure made
with steel columns, electrical train wires,
automotive vehicle, boat, etc.
Cause 3:
You are in an area where magnetism is fluctuating.
Remedy:
Move away from the objects described above.
