JDC Electronic SA Geos 11 - Manual (Page 14)

Resetting the minimum and maximum humidity to zero
Select the middle block and display the measuring mode that you wish to
reset (it flashes), then press the
button for 2 seconds.
Pressure
Measuring modes
altitude altitude pressure height pressure flight level
maximum relative (QNH) QFE absolute
The various measuring modes in relation to pressure are displayed on the
lower block. In order to access a measuring mode, select (with the help
of the
button) the lower block (it flashes), then use the button to
change the display on the block and switch from one measuring mode to
another.
Selecting the unit of measurement in relation to altitude
The instrument features 2 units of measurement in relation to altitude:
m (metres) and ft (feet).
To change the unit of measurement, select the lower block (it flashes),
then keep the
button down; when the desired unit appears, release the
button to confirm your choice.
Calibration of the altitude
The instrument calculates altitude by using air pressure. It is
therefore quite normal for the altitude to change when the air
pressure changes. For this reason the instrument needs to be
calibrated as often as possible.
Stabilization of the altitude: each time it is turned on, the instrument
carries out an automatic calibration based on the drift of the weather
driven trend, this in order to avoid displaying an altitude that is too far
off. This calibration does not occur when the data is accessed
instantaneously.
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