7
Operation Guide 3172
Using the Altitude Differential Value
The Altimeter Mode screen includes an altitude differential value that
shows the change in altitude from a reference point you specify. The
altitude differential value is updated each time the watch takes an altitude
reading.
•
The range of the altitude differential value is –3,000 meters (–9,980
feet) to 3,000 meters (9,980 feet).
•
- - -
is displayed in place of the altitude differential value whenever the
measured value is outside the allowable range.
•
See “Using the Altitude Differential Value While Mountain Climbing or
Hiking” for some real-life examples of how to use this feature.
To specify the altitude differential start point
In the Altimeter Mode, press
E
.
•
The watch will take an altitude reading and register the result as the
altitude differential value start point. The altitude differential value will
be reset to zero at this time.
Using the Altitude Differential Value While Mountain Climbing or Hiking
After you specify the altitude differential start point while mountain climbing or hiking, you easily can
measure the change in the altitude between that point and other points along the way.
To use the altitude differential value
1. In the Altimeter Mode, check to make sure that an altitude reading is
on the display.
•
If an altitude reading is not displayed, press
A
to take one. See “To
take an altimeter reading” for details.
2. Use the contour lines on your map to determine the difference in
altitude between your current location and your destination.
3. In the Altimeter Mode, press
E
to specify your current location as the
altitude differential start point.
•
The watch will take an altitude reading and register the result as
the altitude differential value start point. The altitude differential
value will be reset to zero at this time.
4. While comparing the altitude difference you determined on the map
and the watch’s altitude differential value, advance towards your
destination.
•
If the map shows that the difference in altitude between your
location and your destination is +80 meters for example, you know
you will be nearing your destination when the displayed altitude
differential value shows +80 meters.
Specifying a Reference Altitude Value
The altitude readings 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 value whenever one is available
during your climb. After you specify a reference altitude value, the watch adjusts its air-pressure-to-altitude
conversion calculation accordingly.
To specify a reference altitude value
1. In the Altimeter Mode, hold down
E
until the current reference altitude
value starts to fl ash. This is the setting screen.
•
Before the reference altitude value starts to fl ash, the message
SET Hold
will appear on the display. Keep
E
depressed until
SET Hold
disappears.
2. Press
A
(+) or
C
(–) to change the current reference altitude value
by 5 meters (or 20 feet).
•
Specify a reference altitude value based on accurate altitude
information about your current location from a map, etc.
•
You can set the reference altitude value within the range of –10,000
to 10,000 meters (–32,800 to 32,800 feet).
•
Pressing
A
and
C
at the same time returns to
OFF
(no reference
altitude value), so the watch performs air pressure to altitude
conversions based on preset data only.
3. Press
E
to exit the setting screen.
Types of Altitude Data
The watch can maintain two types of altitude data in its memory: manual measurement records, and auto
save values (minimum, maximum, vertical ascent, vertical descent).
•
Use the Data Recall Mode to view data stored in memory. See “Viewing Altitude Records” for details.
Manual Measurement Records
Any time you perform the procedure below in the Altimeter Mode, the watch will create and store a record
with the currently displayed altitude reading, along with the date and time the reading was taken. There is
enough memory to store up to 25 manual measurement records, which are numbered from
REC01
through
REC25
.
To save a manual measurement
1. In the Altimeter Mode, check to make sure that an altitude reading is
on the display.
•
If an altitude reading is not displayed, press
A
to take one. See “To
take an altimeter reading” for details.
2. Hold down
A
until
REC Hold
appears on the display and then
disappears. Release
A
after
Hold
disappears.
•
This will save the currently displayed altitude reading in a manual
measurement record, along with the measurement time and date.
•
The watch will return to the Altimeter Mode screen automatically
after the save operation is complete.
•
There is enough memory to store up to 25 manual measurement
records. If there are already 25 manual measurement records in
memory, the above operation will cause the oldest record to be
deleted automatically to make room for the new one.
Altitude
differential
Altitude
differential
Altitude differential
Altitude differential
Current
location
Destination
altitude
Current
location
Destination
altitude
Altitude differential
Altitude
Altitude differential
Altitude
l l l l l
lll
ll
ll
ll
ll
l l
l l l l l l l l
lll
ll
ll
ll
ll
l l
l l l ll l l l l
lll
ll
ll
ll
ll
l l
l l l l l l l l
lll
ll
ll
ll
ll
l l
l l l
Auto Save Values
Two sets of auto save values (Set 1 and Set 2) are maintained in watch memory.
Set 1
Set 2
Maximum Altitude (
MAX-1
)
Minimum Altitude (
MIN-1
)
Vertical Ascent (
ASC-1
)
Vertical Descent (
DSC-1
)
Maximum Altitude (
MAX-2
)
Minimum Altitude (
MIN-2
)
Vertical Ascent (
ASC-2
)
Vertical Descent (
DSC-2
)
•
These values are checked and updated automatically by the watch as altitude auto measurements are
taken.
How Maximum and Minimum Values Are Updated
While the watch is in the Altimeter Mode, altitude readings are taken automatically at the interval specifi ed
by the altitude auto measurement method. With each reading, the watch compares the current reading
against the
MAX
(
MAX-1
and
MAX-2
) and
MIN
(
MIN-1
and
MIN-2
) values. It will replace the
MAX
value if
the current reading is greater than
MAX
, or the
MIN
value if the current reading is less than
MIN
.
How Vertical Ascent/Descent Values Are Updated
Session start point
20 m
0 m
120 m
320 m
620 m
Session end point
The total Vertical Ascent and Vertical Descent values produced by an Altimeter Mode measurement
session during the example climb illustrated above are calculated as follows.
Vertical Ascent:
q
(300 m) +
e
(620 m) = 920 m
Vertical Descent:
w
(320 m) +
r
(500 m) = 820 m
•
Entering the Altimeter Mode starts a new altitude auto measurement session, but it does not reset the
current
ASC
(
ASC-1
and
ASC-2
) and
DSC
(
DSC-1
and
DSC-2
) values or change them in any way.
This means that the starting
ASC
and
DSC
values for a new Altimeter Mode auto measurement session
are the values that currently are in memory. Each time you complete an Altimeter Mode auto
measurement session by returning to the Timekeeping Mode, the vertical ascent value of the current
session (920 meters in the above example) is added to the session’s starting
ASC
value. Also, the
vertical descent value of the current auto measurement session (
–
820 meters in the above example) is
added to the session’s starting
DSC
value.
•
Note that any change in elevation when ascending that is less than 15 meters (49 feet) is not added to
the vertical ascent value for the current Altimeter Mode auto measurement session. Also, any change in
elevation when descending that is less than
–
15 meters (
–
49 feet) is not added to the vertical descent
value for the current Altimeter Mode auto measurement session.
Note
•
The maximum altitude, minimum altitude, vertical ascent, and vertical descent values are retained in
memory when you exit the Altimeter Mode. To clear values, perform the procedure under “To clear the
contents of a specifi c memory area”.
Using Auto Save Values
The watch maintains two independent sets of auto save values as shown below.
Set 1
Set 2
Maximum Altitude (
MAX-1
)
Minimum Altitude (
MIN-1
)
Vertical Ascent (
ASC-1
)
Vertical Descent (
DSC-1
)
Maximum Altitude (
MAX-2
)
Minimum Altitude (
MIN-2
)
Vertical Ascent (
ASC-2
)
Vertical Descent (
DSC-2
)
The values in Set 1 and Set 2 can be cleared independently of each other. This means you can use them
to keep track of daily and cumulative data as described in the example below.
Example:
Keeping track of data on a three-day climb
Day 1
Clear both Set 1 and Set 2, and start your Day 1 climb.
At the end of the day, both sets of auto save values contain the same data (
MAX-1
=
MAX-2
,
MIN-1
=
MIN-2
, etc.).
Day 2
Clear only Set 1, and start your Day 2 climb. At the end of the day, the values in Set 1 (
MAX-1
,
MIN-1
,
ASC-1
,
DSC-1
) will show the results of Day 2 only. In Set 2,
MAX-2
and
MIN-2
will show the maximum
and minimum altitudes reached over the two-day span.
ASC-2
will show the total vertical ascent for the
two days (Day 1 + Day 2) and
DSC-2
will show the total vertical descent for the two days.
Day 3
Clear only Set 1, and start your Day 3 climb. At the end of the day, the values in Set 1 will show the
results of Day 3 only. In Set 2,
MAX-2
and
MIN-2
will show the maximum and minimum altitudes
reached over the three-day span.
ASC-2
will show the total vertical ascent for the three days (Day 1 +
Day 2 + Day 3) and
DSC-2
will show the total vertical descent for the three days.
•
For details about clearing altitude data, see “To clear the contents of a specifi c memory area”.
How does the altimeter work?
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 defi ne relationships between altitude, air pressure, and
temperature.
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°C
1013 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
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°F
29.92 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
•
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