E-79
Reading Barometric Pressure Differential Pointer
Pressure differential is indicated in the
range of ±10 hPa (0.3 inHg), in 1-hPa (0.03
inHg) units.
•
The nearby screen shot, for example,
shows what the small hand would
indicate when the calculated pressure
differential is approximately – 5 hPa
(approximately –0.15 inHg).
•
The small hand will point to
OVER
or
UNDER
if the barometric
pressure differential is outside the
allowable range of the scale.
•
The small hand will move to 12 o’clock if
a sensor reading could not be taken for
some reason or if the reading is outside
the allowable range.
•
Barometric pressure is calculated and
displayed using hPa as the standard.
The barometric pressure differential also
can be read in inHg units as shown in
the illustration (1 hPa
=
0.03 inHg).
Current pressure greater
than most recent
measured pressure
Current pressure
less than most
recent measured
pressure
inHg values
hPa values
Barometric pressure
differential pointer
–10
–0.3
0
0
0.3
10
E-78
To specify the barometric pressure auto measurement interval
1. In the Barometer Mode, pull out the crown.
•
This will cause the current barometric pressure reading value to
fl ash on the display.
2. Press
B
.
•
This causes
INT
(interval) to appear on the display, with the current
setting (
0:30
or
2:00
) fl ashing.
3. Rotate the crown to select either
0:30
or
2:00
.
4. Push the crown back in.
•
This completes the setting procedure and exits the setting screen.
Barometric Pressure Differential Pointer
This pointer indicates the relative difference between the most recent
barometric pressure reading indicated on the Barometric Pressure Graph
(page E-76), and the current barometric pressure value displayed in the
Barometer Mode (page E-75).
To enable barometric pressure differential indication by the small
hand
Use
B
to enter the Barometer Mode (
BARO
), as shown on page E-32.
•
This causes the small hand to indicate the barometric pressure
differential.
l ll
lll
ll
ll
ll
ll
l l l l l
Barometric pressure
differential pointer
E-77
How to interpret the data that appears on the Barometric Pressure Graph is shown below.
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 conditions below 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.
Specifying the Barometric Pressure Auto Measurement Interval
You can select either of two barometric pressure auto measurement interval times for drawing the
Barometric Pressure Graph.
0:30: 30-minute measurement interval
2:00: 2-hour measurement interval
Not visible on
the display.
E-76
Barometric Pressure
•
Barometric pressure is displayed in units of 1 hPa (or 0.05 inHg).
•
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-58).
Barometric Pressure Graph
Barometric pressure indicates changes in the atmosphere. By monitoring
these changes you can predict the weather with reasonable accuracy.
Your watch can be confi gured to take barometric pressure reading
automatically every two hours or every 30 minutes. Readings are used to
produce Barometric Pressure Graph and to determine the barometric
pressure differential pointer position.
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 either two hours or 30 minutes (depending on the watch
settings). The rightmost dot represents the most recent reading.
•
The vertical axis of the graph represents barometric pressure, with
each dot standing for the relative difference between its value and that
of the dots next to it. Each dot represents 1 hPa.
Barometric Pressure Graph
Barometric
pressure
Time
E-75
Taking Barometric Pressure Readings
This watch uses a pressure sensor to measure air pressure (barometric pressure).
To take barometric pressure readings
Use
B
to select the Barometer Mode (
BARO
), as shown on page E-32.
•
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.
Barometric
Pressure Graph
Barometric
pressure
E-74
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 readings, keep the watch at as stable a temperature as possible. Changes in temperature
can affect readings.
E-73
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-72
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 conditions below 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.
Sea Level
Rooftop at an altitude of
230 m above sea level
(absolute 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-62).
Operation Guide 5480