Operation Guide 3172
Using the Altitude Differential Value
Altitude | The Altimeter Mode screen includes an altitude differential value that | ||
shows the change in altitude from a reference point you specify. The | |||
differential | |||
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| altitude differential value is updated each time the watch takes an altitude | |
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| reading. | |
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| • The range of the altitude differential value is | |
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| feet) to 3,000 meters (9,980 feet). | |
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| • - - - is displayed in place of the altitude differential value whenever the | |
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| measured value is outside the allowable range. | |
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| • See “Using the Altitude Differential Value While Mountain Climbing or | |
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| Hiking” for some | |
To specify the altitude differential start point
In the Altimeter Mode, press E.
Altitude differential• 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
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 | Maximum Altitude |
Minimum Altitude | Minimum Altitude |
Vertical Ascent | Vertical Ascent |
Vertical Descent | Vertical Descent |
•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 specified by the altitude auto measurement method. With each reading, the watch compares the current reading against the MAX
How Vertical Ascent/Descent Values Are Updated
620 m
Session end point
Session start point
320 m
120 m
20 m 
0 m
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.
Destination altitude
Current location
Altitude differential
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.
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
•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
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 specific memory area”.
Altitude
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
To specify a reference altitude value
Using Auto Save Values
The watch maintains two independent sets of auto save values as shown below.
Set 1 | Set 2 |
Maximum Altitude | Maximum Altitude |
Minimum Altitude | Minimum Altitude |
Vertical Ascent | Vertical Ascent |
Vertical Descent | Vertical Descent |
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.
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1.In the Altimeter Mode, hold down E until the current reference altitude value starts to flash. This is the setting screen.
•Before the reference altitude value starts to flash, the message SET Hold will appear on the display. Keep E depressed until SET Hold disappears.
2.Press A (+) or C
•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
•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.
Example: Keeping track of data on a
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
Day 2
Clear only Set 1, and start your Day 2 climb. At the end of the day, the values in Set 1
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
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.
results of Day 3 only. In Set 2,
•For details about clearing altitude data, see “To clear the contents of a specific 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 define relationships between altitude, air pressure, and temperature.
Altitude |
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4000 m |
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| 616 hPa |
| About 8 hPa per 100 m |
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3500 m |
| 701 hPa |
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3000 m |
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| About 9 hPa per 100 m |
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| About 6.5°C | |||||
2500 m |
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795 hPa |
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| 2°C per 1000 m | |||||||||
2000 m |
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| About 10 hPa per 100 m |
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1500 m |
| 899 hPa |
| About 11 hPa per 100 m |
| 8.5°C |
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1000 m |
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500 m | 1013 hPa |
| About 12 hPa per 100 m |
| 15°C |
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0 m |
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14000 ft. | 19.03 inHg |
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| 16.2°F |
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12000 ft. |
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| About 0.15 inHg per 200 ft. |
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10000 ft. | 22.23 inHg |
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| 30.5°F |
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8000 ft. |
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| About 0.17 inHg per 200 ft. |
| About 3.6°F | ||||||||
6000 ft. | 25.84 inHg |
| About 0.192 inHg per 200 ft. | 44.7°F | per 1000 ft. | |||||||||
4000 ft. |
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2000 ft. | 29.92 inHg |
| About 0.21 inHg per 200 ft. | 59.0°F |
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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
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