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Barometric Pressure
Barometric pressure
Barometric pressure
•
Barometric pressure is displayed in units of 1 hPa (or 0.05 inHg).
change indicator
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.
Temperature
•
Temperature is displayed in units of 0.1°C (or 0.2°F).
•
The displayed temperature value changes to - - - °C (or °F) if a
measured temperature falls outside the range of –10.0°C to 60.0°C
(14.0°F to 140.0°F). The temperature value will reappear as soon as
Barometric
Barometric
Temperature
Temperature
the measured temperature is within the allowable range.
pressure
pressure
Display Units
You can select either hectopascals (hPa) or inchesHg (inHg) as the display unit for the measured
barometric pressure, and Celsius (°C) or Fahrenheit (°F) as the display unit for the measured temperature
value. See "To specify temperature, barometric pressure, and altitude display units" (page E-29).
E-32
Barometric Pressure Graph
Barometric pressure indicates changes in the atmosphere. By monitoring
Barometric pressure graph
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.
Reading the Barometric Pressure Graph
The barometric pressure graph shows a chronological history of pressure readings.
•
When display of the barometric change indicator is disabled, the graph shows the results of up to 21
barometric pressure readings (42 hours).
•
When display of the barometric change indicator is enabled, the graph shows the results of up to 11
barometric pressure readings (22 hours).
•
The vertical axis of the graph represents barometric pressure, with each
Barometric
Barometric
dot standing for the relative difference between its reading and that of the
pressure
pressure
dots next to it. Each dot represents 1 hPa.
•
The horizontal axis of the graph represents time, with each dot standing for
two hours. The rightmost dot represents the most recent reading.
Time
Time
E-34
Reading the Barometric Pressure Change Indicator
Indicator
Meaning
Sudden fall in pressure.
Sudden rise in pressure.
Sustained rise in pressure, changing to a fall.
Sustained fall in pressure, changing to a rise.
•
The barometric pressure change indicator is not displayed if there has been no noteworthy change in
barometric pressure.
Important!
•
To ensure proper results, take barometric readings under conditions where the altitude remains
constant.
•
A change in altitude causes a change in barometric pressure. This means that correct barometric
pressure readings are not possible while you are changing altitudes. To avoid possible confusion, it is
probably best to disable the barometric pressure change indicator while you are on the move during
your climb.
E-36
To calibrate the pressure sensor and the temperature sensor
1. Take a reading with another measurement device to determine the
exact current barometric pressure or temperature.
2. With the watch in the Timekeeping Mode or in any of the sensor
modes, press B to enter the Barometer/Thermometer Mode.
3. Hold down E for at least two seconds. SET Hold will fl ash on the
display and then TEMP will appear in the upper display. Keep E
depressed until TEMP appears.
•
The current temperature calibration setting will fl ash in the lower
display at this time.
4. Press D to move the fl ashing between the temperature value and
barometric pressure value, to select the one you want to calibrate.
5. Use A (+) and C (–) to change the fl ashing temperature or altitude
value. The values can be change in the units shown below.
Temperature
Barometric Pressure
•
To return the currently fl ashing value to its initial factory default
setting, press A and C at the same time. OFF will appear at
the fl ashing location for about one second, followed by the initial
default value.
6. Press E to return to the Barometer/Thermometer Mode screen.
E-38
Operation Guide 3439
0.1°C (0.2°F)
1 hPa (0.05 inHg)
Barometric Pressure Differential Pointer
This pointer indicates the relative difference between the most recent
Barometric
Barometric
barometric pressure reading indicated on the barometric pressure graph
pressure
pressure
(page E-34), and the current barometric pressure value displayed in the
differential
differential
Barometer/Thermometer Mode (page E-32).
pointer
pointer
Reading Barometric Pressure Differential Pointer
Pressure differential is indicated in the range of
±10 hPa, in 1-hPa units.
•
The nearby screen shot, for example, shows
what the pointer would indicate when the
calculated pressure differential is
approximately – 5 hPa (approximately – 0.15
inHg).
•
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).
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 entire graph will become visible once
barometric conditions stabilize.
•
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
Barometric Pressure Change Indications
Your watch analyzes past barometric pressure readings and uses a barometric pressure change indicator
to inform you about changes in pressure. If it determines there has been a signifi cant change in pressure,
it will beep and all of the graphic segments (
pressure change alert. This means you could start taking barometric pressure readings after reaching a
lodge or camp area, and then check the watch the next morning for changes in pressure, and plan you
day's activities accordingly. Note that you can enable or disable display of the barometric pressure change
indicator as desired.
To enable or disable the barometric pressure change alert
In the Barometer/Thermometer Mode, hold down B for at least two seconds. Keep B depressed until
the current setting (INFO Hold ON or INFO Hold OFF) starts to fl ash on the display.
•
If barometric pressure change indicator display is currently enabled, BARO will also appear in the
upper display. BARO will not appear if display is currently disabled.
Pressure Sensor and Temperature Sensor Calibration
The pressure sensor and temperature sensor built into the watch are calibrated at the factory and normally
require no further adjustment. If you notice serious errors in the pressure readings and temperature
readings produced by the watch, you can calibrate the sensor to correct the errors.
Important!
•
Incorrectly calibrating the barometric pressure sensor can result in incorrect readings. Before
performing the calibration procedure, compare the readings produced by the watch with those of
another reliable and accurate barometer.
•
Incorrectly calibrating the temperature sensor can result in incorrect readings.
Carefully read the following before doing anything.
– Compare the readings produced by the watch with those of another reliable and accurate thermometer.
– If adjustment is required, remove the watch from your wrist and wait for 20 or 30 minutes to give the
temperature of the watch time to stabilize.
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 offi cial weather
prediction or reporting applications.
•
Sudden temperature changes can affect pressure sensor readings. Because of this, there may be
some error in the readings produced by the watch.
•
Temperature reading are affected by your body temperature, direct sunlight, and moisture. To achieve
a more accurate temperature reading, 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 surrounding temperature.
Current pressure
Current pressure
greater than most
greater than most
inHg values
inHg values
recent measured
recent measured
pressure
pressure
hPa values
hPa values
−5
−5
−0.15
−0.15
−10
−10
Current pressure
Current pressure
Barometric pressure
Barometric pressure
−0.3
−0.3
differential pointer
differential pointer
less than most
less than most
recent measured
recent measured
pressure
pressure
) around the periphery of the face will fl ash as a barometric
E-33
Not visible on
Not visible on
the display.
the display.
E-35
E-37
E-39
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