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•
Entering the Altimeter Mode starts a new altitude auto reading session, but it does not reset the current
ASC and DSC values or change them in any way. This means that the starting ASC and DSC values for
a new Altimeter Mode auto reading session are the values that currently are in memory. Each time you
complete an altitude auto reading session by exiting the Altimeter Mode, the total ascent value of the
current session (920 meters in the above example) is added to the session's starting ASC value. Also,
the total descent value of the current auto reading session (–820 meters in the above example) is
added to the session's starting DSC value.
Note
•
The high altitude, low altitude, total ascent, and total descent values are retained in memory when you
exit the Altimeter Mode. To clear values, perform the procedure under "To delete a specifi c record"
(page E-83).
E-64
Altimeter Precautions
•
This watch estimates altitude based on air pressure. This means that altitude readings for the same
location may vary if air pressure changes.
•
Do not use this watch for altitude reading or perform button operations while sky diving, hang gliding,
or paragliding, while riding a gyrocopter, glider, or any other aircraft, or while engaging in any other
activity where there is the chance of sudden altitude changes.
•
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 fl ight crew.
E-66
Taking Barometric Pressure Readings
This watch uses a pressure sensor to measure air pressure (barometric pressure).
To take barometric pressure readings
Barometric
Use B to select the Barometer Mode (BARO), as shown on page E-30.
pressure graph
•
BARO will appear on the display, indicating that barometric pressure
reading is in progress. The results will appear on the display after
about one second.
•
After a barometric pressure reading operation is started, the watch will
take readings every fi ve seconds for the fi rst three minutes, and then
every two minutes after that.
To restart a reading operation from the beginning, press A.
•
•
The watch will return to the Timekeeping Mode automatically if you do
not perform any operation for about one hour after entering the
Barometer Mode.
Note
Barometric
When you press B above, the second hand may indicate seconds (of
•
pressure
the current time) or the barometric pressure differential (page E-71). The
initial second hand function will be the same as what was selected the
last time you took a barometric pressure reading. To toggle between
the two second hand functions (indicating seconds or indicating the
barometric pressure differential) press D.
E-68
Reading the Barometric Pressure Graph
The barometric pressure graph shows a chronological history of pressure readings.
•
The horizontal axis of the graph represents time, with each dot
standing for two hours. The rightmost dot represents the most recent
Barometric
reading.
pressure
•
The vertical axis of the graph represents barometric pressure, with
each dot standing for the relative difference between its reading and
Time
that of the dots next to it. Each dot represents 1 hPa.
The following shows how to interpret the data that appears on the barometric pressure graph.
Rising barometric pressure indicates that upcoming weather will improve.
Falling barometric pressure indicates that upcoming weather will deteriorate.
Note
•
If there are sudden changes in weather or temperature, the graph line of past reading
may run off the top or bottom of the display.
•
The following conditions cause the barometric pressure reading to be skipped, with
the corresponding point on the barometric pressure graph being left blank.
– Barometric reading that is out of range (260 hPa to 1,100 hPa or 7.65 inHg to 32.45
inHg)
– Sensor malfunction
•
The barometric pressure graph is not displayed while the barometric pressure change indicator is
displayed.
E-70
Operation Guide 5571
Not visible on
the display.
How does the altimeter work?
Generally, air pressure decreases as altitude increases. This watch bases its altitude reading on
International Standard Atmosphere (ISA) values stipulated by the International Civil Aviation Organization
(ICAO). These values defi ne relationships between altitude and air pressure.
•
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, which expresses an absolute
height above sea level, and relative altitude, which expresses the difference between the altitudes of two
different places. This watch expresses altitudes as relative altitude.
Height of building 130 m
(relative altitude)
Regular calibration of the watch in accordance with values provided by local altitude (elevation) indications
is recommended before taking readings in order to maximize reading accuracy (page E-55).
Precautions Concerning Simultaneous Altitude and Temperature Readings
For the more accurate altitude readings, leaving the watch on your wrist is recommended in order to
maintain the watch at a constant temperature.
•
When taking temperature readings, keep the watch at as stable a temperature as possible. Changes in
temperature can affect temperature readings. See product specifi cations (page E-107) for sensor accuracy
information.
Barometric Pressure
Barometric pressure
•
Barometric pressure is displayed in units of 1 hPa (or 0.05 inHg).
change indicator
•
The displayed barometric pressure value changes to - - - if a measured
barometric pressure falls outside the range of 260 hPa to 1,100 hPa
(7.65 inHg to 32.45 inHg). The barometric pressure value will reappear
as soon as the measured barometric pressure is within the allowable
range.
Display Units
You can select either hectopascals (hPa) or inchesHg (inHg) as the
display unit for the measured barometric pressure. See "To specify
altitude, barometric pressure, and temperature units" (page E-51).
Barometric pressure
Barometric Pressure Graph
Barometric pressure indicates changes in the atmosphere. By monitoring
Barometric pressure graph
these changes you can predict the weather with reasonable accuracy.
This watch takes barometric pressure reading automatically every two
hours. Readings are used to produce barometric pressure graph and
barometric pressure differential pointer readings.
Barometric Pressure Differential Pointer
This pointer indicates the relative difference between the most recent
Barometric
barometric pressure reading indicated on the barometric pressure graph
pressure
(page E-69), and the current barometric pressure value displayed in the
differential
Barometer Mode (page E-68).
pointer
To show and hide barometric pressure differential
1. Use B to enter the Barometer Mode (BARO), as shown on page E-30.
2. Press D.
Note
Press D to toggle the second hand between its two functions (indicating seconds or indicating the
•
barometric pressure differential).
Rooftop at an altitude of
230 m above sea level
(absolute altitude)
Sea Level
E-65
E-67
E-69
E-71
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