JDC Electronic SA Geos 11 - Manual (Page 18)

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here are two types of compass display:
the compass block (always
al display on the lower block. Select
bargraph on
visible)
and digit
the lower block with the
button (it flashes),
then display the compass using the button.
HICH MEANS : The default setting of the compass is for the magnetic W
North, and not for true North. It is however possible for the instrument to
display it, provided the value of the magnetic declination has been
entered; see ‘Special Modes’; ‘Magnetic Field’.
Remark: The compass displays
if it has never been calibrated,
or if it cannot give the heading, when the instrument is at too much of
angle for instance
Calibration
IMPORTANT ! Calibrate the compass before you use it for the
first time. At a later stage, we advise you to recalibrate your
compass each time you are in a new environment or whenever
you change the batteries.
Select the lower block and display the compass (it flashes), then keep the
button pressed down for 2 seconds, starts flashing on the upper
ock. Release the bl button as soon as you access calibration. To
calibrate the compass, hold the instrument vertically and turn around
once slowly in a circle (or the instrument alone). Each time a cardinal
point is acquired, a section of the ‘square’ symbol lights up on the large
block. The calibration process is complete when the whole symbol is
displayed ( ); calibration is complete. Confirm and exit the calibration
by keeping the button down. The instrument goes back to the standard
screen.
The level of magnetic field expressed in micro Tesla (µT) and displayed
tion
on the lower block during the calibration is the mean value measured by
the sensors, compensated by the previous calibration. While carrying out
a revolution, the microprocessor measures all the field values detected
according to directions, in order to eventually isolate the earth’s
magnetic field while removing the local disturbing magnetisations.
At a later stage, the instrument will need to be in the same posi
as during the calibration in order to provide an accurate reading of
heading.