Operation Guide 5113 5213
The total Cumulative Ascent and Cumulative Descent values produced by an Altimeter Mode measurement session during the example climb illustrated above are calculated as follows.
Cumulative Ascent: q (300 m) + e (620 m) = 920 m
Cumulative 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 and DSC 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 cumulative ascent value of the current session (920 meters in the above example) is added to the session’s starting ASC value. Also, the cumulative descent value of the current auto measurement session
•Note that any change in elevation when ascending that is less than 15 meters (49 feet) is not added to the cumulative ascent value for the current Altimeter Mode auto measurement session. Also, any change in elevation when descending that is less than
Note
•The high altitude, low altitude, cumulative ascent, and cumulative descent values are retained in memory when you exit the Altimeter Mode. To clear values, perform the procedure under “To delete a single altitude record” (page
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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0 ft. |
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Source: International Civil Aviation Organization
•Note that the following conditions will prevent you from obtaining accurate readings: When air pressure fluctuates 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 and relative altitude. Absolute altitude expresses an absolute height above sea level. Relative altitude expresses the difference between the height of two different places.
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| Height of building 130 m |
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| (relative altitude) |
| 230 m above sea level | |||||||||
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| Sea Level | |||
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.
•The semiconductor pressure sensor used by the watch for altitude measurements is also affected by temperature. When taking altitude measurements, do not subject the watch to temperature changes.
•Do not rely upon this watch for altitude measurements 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 the flight crew.
Specifying Temperature, Barometric Pressure, and Altitude Units
Use the procedure below to specify the temperature, barometric pressure, and altitude units to be used in the Barometer/Thermometer Mode and the Altimeter Mode.
Important!
When TOKYO (TYO) is selected as the Home City, the altitude unit is set automatically to meters (m), the barometric pressure unit to hectopascals (hPa), and the temperature unit to Celsius (°C). These settings cannot be changed.
To specify temperature, barometric pressure, and altitude units
1.In the Timekeeping Mode, hold down E until each of the following steps occurs.
•Hold SET appears on the digital display. ➝ HT flashes. ➝ Second hand points to the current Home City code.
2.Use D to cycle through the settings on the digital display until the unit setting screen is shown.
•See step 3 under “To change the current time and date settings” (page
3. Perform the operations below to specify the units you want.
To specify this unit: | Press this key: | To toggle between these settings: |
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Altitude | A | m (meters) and ft (feet) |
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Barometric Pressure | B | hPa (hectopascals) and inHg (inches of mercury) |
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Temperature | C | °C (Celsius) and °F (Fahrenheit) |
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4. After the settings are the way you want, press E to exit the setting screen.
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Precautions Concerning Simultaneous Measurement of Altitude and Temperature
Though you can perform altitude and temperature measurements at the same time, you should remember that each of these measurements requires different conditions for best results. With temperature measurement, it is best to remove the watch from your wrist in order to eliminate the effects of body heat. In the case of altitude measurement, on the other hand, it is better to leave the watch on your wrist, because doing so keeps the watch at a constant temperature, which contributes to more accurate altitude measurements.
•To give altitude measurement priority, leave the watch on your wrist or in any other location where the temperature of the watch is kept constant.
•To give temperature measurement priority, remove the watch from your wrist and allow it to hang freely from your bag or in another location where it is not exposed to direct sunlight. Note that removing the watch from your wrist can affect pressure sensor readings momentarily.
Viewing Altitude Records
Use the Data Recall Mode to view manual save altitude records and automatically saved high altitude, low altitude, cumulative ascent, and cumulative descent values. Altitude records are created and saved in the Altimeter Mode.
To view altitude records
1. Use D to select the Data Recall Mode (REC) as shown on page
| 2. Use A and C to scroll through altitude records in the sequence |
| shown on page |
| • For a manual save record, high altitude and low altitude records, the |
| month and day of the reading will appear first. After about one |
| second, this will change to show the time of the reading. After that |
| the time and altitude reading will alternate on the digital display |
| at |
Record name | descent, the digital display will show the month and day of the |
| first reading. After about one second, this will change to show the |
| cumulative altitude. |