User's Manual

Operation Guide 2782
6
Questions & Answers
Question: How does the altimeter work?
Answer: Generally, air pressure and temperature decrease as altitude
increases. This watch bases its altitude measurements on
International Standard Atmosphere (ISA) values stipulated by the
International Civil Aviation Organization (ICAO). These values
define relationships between altitude, air pressure, and
temperature.
0 ft
2000 ft
4000 ft
6000 ft
8000 ft
10000 ft
12000 ft
14000 ft
25.84 inHg
22.23 inHg
19.03 inHg
44.7°F
30.5°F
16.2°F
59.0°F29.92 inHg
About 3.6°F
per 1000 ft
About 0.15 inHg per 200 ft
About 0.17 inHg per 200 ft
About 0.192 inHg per 200 ft
About 0.21 inHg per 200 ft
Source: International Civil Aviation Organization
0 m
500 m
1000 m
1500 m
2000 m
2500 m
3000 m
3500 m
4000 m
899 hPa
795 hPa
701 hPa
616 hPa
8.5°C
2°C
–4.5°C
–11°C
15°C1013 hPa
About 6.5°C
per 1000 m
About 8 hPa per 100 m
About 9 hPa per 100 m
About 10 hPa per 100 m
About 11 hPa per 100 m
About 12 hPa per 100 m
Altitude Air Pressure Temperature
• Note that the following conditions will prevent you from obtaining accurate
readings:
When air pressure changes because of changes in the weather
Extreme temperature changes
When the watch itself is subjected to strong impact
There are two standard methods of expressing altitude: Absolute altitude and
relative altitude. Absolute altitude expresses an absolute height above sea
level. Relative altitude expresses the difference between the height of two
different places.
Height of building 130 m
(Relative altitude)
Rooftop at an altitude of
230 m above sea level
(Altitude above sea
level)
Sea
Precautions Concerning Simultaneous Measurement of Altitude and
Temperature
Though you can perform altitude and temperature measurements at the same
time, you should remember that each of these measurements requires
different conditions for best results. With temperature measurement, it is best
to remove the watch from your wrist in order to eliminate the effects of body
heat. In the case of altitude measurement, on the other hand, it is better to
leave the watch on your wrist, because doing so keeps the watch at a
constant temperature, which contributes to more accurate altitude
measurements.
The following describes what you should do to give priority to either altitude or
temperature.
• To give altitude measurement priority, leave the watch on your wrist or in
any other location where the temperature of the watch is kept constant.
• To give temperature measurement priority, remove the watch from your
wrist and allow it to hang freely from your bag or in another location where
it is not exposed to direct sunlight. Note that removing the watch from your
wrist can momentarily affect pressure sensor readings.
Question: How does the barometer work?
Answer: Barometric pressure indicates changes in the atmosphere, and by
monitoring these changes you can predict the weather with
reasonable accuracy. Rising atmospheric pressure indicates good
weather, while falling pressure indicates deteriorating weather
conditions.
The barometric pressures that you see in the newspaper and on
the TV weather report are measurements corrected to values
measured at 0 m sea level.
Question: How does the watch calculate depth values?
Answer: Water pressure increases with depth. In the case of sea water
(specific gravity=1.025), water pressure increases by 1 ATM
(1.03 kg/cm
2
) with each 10 meters (33 feet) of depth.
This watch takes advantage of the relationship between pressure
and depth using a pressure sensor to measure water pressure,
which it then converts to a depth reading.
Question: Is there anything I need to keep in mind when diving at high
altitudes or in fresh water?
Answer: The depth reading is automatically reset to “0.0 m (0 ft)” whenever
the Depth Gauge Mode is entered, so you can use this watch for
skin diving at altitudes. Note, however, that malfunctions occur
when skin diving at altitudes greater than approximately 4,000
meters (13,000 ft.). In addition, as this watch bases its
calculations on sea water, which has a specific gravity of 1.025,
readings will be incorrect during fresh-water skin diving. During
fresh-water dives, you must assume that you are approximately
2.5% deeper than the depth shown on the display.
Example: When displayed depth is 5 meters, actual depth is
5 × 1.025 = 5.1 meters.
Reference
This section contains more detailed and technical information about watch
operation. It also contains important precautions and notes about the various
features and functions of this watch.
Auto Return Features
• The watch automatically returns to the Timekeeping Mode if you do not
perform any button operation for two or three minutes in the Barometer/
Thermometer Mode.
• If you do not perform any button operation while in the Altimeter Mode, the
watch automatically returns to the Timekeeping Mode after nine or 10
hours.
• The watch automatically returns to the Timekeeping Mode if a depth
measurement operation in the Depth Gauge Mode continues for more than
three hours. If there is no depth measurement operation being performed,
the watch automatically returns to the Timekeeping Mode if you do not
perform any button operation for about one hour in the Depth Gauge Mode.
• If you leave a screen with flashing digits on the display for two or three
minutes without performing any operation, the watch automatically exits the
setting screen.
Scrolling
The B and D buttons are used in various modes and setting screens to
scroll through data on the display. In most cases, holding down these buttons
during a scroll operation scrolls through the data at high speed.
Sensor Malfunction Indicator
Should the pressure sensor malfunction, the message Err will appear on
the display and sensor operations will be disabled.
• If an error occurs during depth measurement,
Err
appears on the display
for about one or two seconds. After that,
Err
is replaced by .
• If
Err appears while a measurement operation is being performed in the
Barometer/Thermometer Mode, Altimeter Mode, or Depth Gauge Mode,
restart the measurement. If
Err
appears on the display again, it can mean
there is something wrong with the sensor.
Whenever you have a sensor malfunction, be sure to take the watch to
your original dealer or nearest authorized CASIO distributor as soon as
possible.
Barometric Pressure
Measurement
Altitude
Measurement
Depth
Measurement
BATTERY and RECOVER Indicators
The BATTERY indicator flashes on the display
whenever battery power drops below a certain
level. All of the following functions are disabled
while the BATTERY indicator is flashing on the
display.
All sensor operations
Backlight
All alarm beepers
Analog hand setting
• While the BATTERY indicator is flashing on the display, the indicated
barometric pressure and temperature values are the last values measured
before battery power went low.
• To avoid problems while diving, it is recommended that you have the
battery replaced even before the BATTERY indicator appears when you are
diving frequently.
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• Note that low temperatures decrease battery performance. Frequent use of
the backlight when the temperature is very low can cause the BATTERY
indicator to appear, even though the watch battery is relatively new. Normal
battery performance should return when the watch is brought back to
normal temperature. If you need to use the backlight frequently when
temperature is low, be sure to leave the watch on your wrist so it is warmed
by your body heat.