Casio 2872 Operation Manual page 3

About Barometric and Temperature Measurements
• Barometric pressure and temperature measurement operations are
performed as soon as you enter the Barometer/Thermometer Mode. After
that, barometric pressure and temperature measurements are taken every
five seconds.
• The barometer automatically takes measurements every three hours
(starting from midnight), regardless of what mode you are in. The results of
these measurements are used for positioning indicators in the barometric
pressure indicator display area.
• You can also perform a barometric pressure and temperature measurement
at any time by pressing E in the Barometer/Thermometer Mode.
Barometer and Thermometer Precautions
• The pressure sensor built into this watch measures changes in air
pressure, which you can then apply to your own weather predictions. It is
not intended for use as a precision instrument in official weather prediction
or reporting applications.
• Sudden temperature changes can affect pressure sensor readings.
• Temperature measurements are affected by your body temperature (while
you are wearing the watch), direct sunlight, and moisture. To achieve a
more accurate temperature measurement, remove the watch from your
wrist, place it in a well ventilated location out of direct sunlight, and wipe all
moisture from the case. It takes approximately 20 to 30 minutes for the
case of the watch to reach the actual surrounding temperature.
Altimeter
A built-in altimeter uses a pressure sensor to detect the current air pressure,
which is then used to estimate the current altitude. The watch is pre-
programmed with ISA (International Standard Atmosphere) preset values,
which are used to convert air pressure readings to altitude values. If you
preset a reference altitude, the watch will also calculate the current relative
altitude based on your preset value. Memory is also provided for the storage
of altimeter data.
Important!
• This watch estimates altitude based on air pressure. This means that
altitude readings for the same location may vary if air pressure changes.
• This watch employs a semiconductor pressure sensor, which is affected by
temperature changes. Make sure that the watch is not being exposed to
temperature changes while you are taking altitude measurements.
• To avoid the effect of sudden temperature changes on measurement, wear
the watch so it is in direct contact with your wrist during measurement.
• Do not rely upon this watch for altitude measurements or perform button
operations while engaging in sports where there are sudden altitude
changes, while sky diving, hang gliding, or paragliding, or while riding a
gyrocopter, glider, or any other aircraft.
• Do not use this watch for measuring altitude in applications that demand
professional or industrial level precision.
• Remember that the air inside of a commercial aircraft is pressurized.
Because of this, the readings produced by this watch will not match the
altitude readings announced or indicated by the flight crew.
How the Altimeter Works
With the Preset Values (No Reference Altitude)
• The watch measures the air pressure at your current location and uses the
built-in ISA values to convert it to the equivalent altitude.
With a Reference Altitude
• If you set a reference altitude, the watch
uses that value when calculating altitude
based on air pressure.
• To determine the height of a tall building,
set the reference altitude to 0 on the
ground floor. Note, however, that you may
not be able to get a good reading if the
building is pressurized or air-conditioned.
• When mountain climbing, you can set the
reference value in accordance with a
marker along the way or altitude
information from a map. After you do this,
the altitude readings produced by the
watch will be more accurate than they
would be without a reference altitude.
Operation Guide 2872
B
A
400
To take an altitude reading
Pressing D in the Timekeeping Mode or in any
of the other sensor modes enters the Altimeter
Altitude indicator
Mode and automatically starts altitude
Temperature
measurement.
• It can take up to four or five seconds for the
altitude reading to appear after you enter the
Altimeter Mode.
• The Altimeter Mode screen also displays the
current temperature. See "Barometer/
Thermometer" for more information.
l
• During the first three minutes after entering the
Altitude
Altimeter Mode, the
Timekeeping Mode
display and measurements are taken every five
time
seconds. After that, the
as measurements are taken every two minutes.
• Pressing D causes the measurement operation to restart from the
beginning of the cycle described above.
• Altitude is displayed in units of 5 meters (20 feet).
• The measurement range for altitude is –700 to 10,000 meters (–2,300 to
32,800 feet).
• The measured altitude may be a negative value in cases where there is a
reference altitude value set or because of certain atmospheric conditions.
• The displayed altitude value changes to
measured altitude falls outside the measurement range. The altitude value
will be displayed again as soon as the measured altitude is within the
allowable range.
• You can change the unit of measurement for the displayed altitude values
between meters (m) and feet (ft). See "To change the altitude unit".
Altitude Indicator
In the Altimeter Mode, the altitude indicator shows the current altitude reading
in meters (m). As shown in the illustration below, the altitude indicator is
divided into two zones: one for 0 to 999 meters, and one for 1000 to 10,000
meters.
Though you can specify either meters or feet for the watch's altitude
measurements, the altitude indicator always shows altitude in meters.
1000+ meter zone
The above altitude indicator indicates an altitude of approximately 4,340 meters.
• The 0-999 meter zone starts from the 12 o'clock position (0 meters), and
indicates altitudes in 20-meter units.
• The 1000+ meter zone indicates altitudes in 1000-meter units.
Setting a Reference Altitude
After you set a reference altitude, the watch adjusts its air-pressure-to-altitude
conversion calculation accordingly. The altitude measurements produced by
this watch are subject to error caused by changes in air pressure. Because of
this, we recommend that you update the reference altitude whenever one is
available during your climb.
To set a reference altitude
1. In the Altimeter Mode, hold down A until
OFF
goes blank. This is the setting screen.
• If the display goes blank, it means there is a
reference altitude value. Release A and
wait for four or five seconds until the value
appears.
2. Press D (+) or B (–) to change the current
reference altitude value by 5 meters (or 20
feet).
• You can set the reference altitude within the range of –10,000 to 10,000
meters (–32,800 to 32,800 feet).
• Pressing D and B at the same time returns to
altitude), so the watch performs air pressure to altitude conversions
based on preset data only.
3. Press A to exit the setting screen.
indicator flashes on the
indicator disappears
xxxx meters (or feet) if a
x
0-999 meter zone
(flashing) appears or until the display
OFF (no reference
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