
Operation Guide 4798
Timekeeping
| Use the Timekeeping Mode to set and view the current |
Hour hand | time and date. This section also explains how to set the |
Minute hand | current date and time manually. |
| • All of the operations in this section are performed in the |
| Timekeeping Mode, which you enter by pressing C. |
Date
Second hand
Setting the Time and Date Manually
Make sure you select your Home Time Zone before you change the current time and date settings. Dual Time Mode times are all displayed in accordance with the Timekeeping Mode settings. Because of this, Dual Time Mode times will not be correct if you do not select the proper Home Time Zone before setting the time and date in the Timekeeping Mode.
•When setting the time and date, you also can configure settings for your Home Time Zone (the time zone where you normally use the watch) and summer time (Daylight Saving time or DST).
To set the time and date manually
Illumination
An LED
• The auto light switch must be turned on for it to operate.
• See “Illumination Precautions” for other important information.
To illuminate the face of the watch
In the Timekeeping Mode (except when a setting screen is on the display), press B to illuminate the face of the watch for about one second.
•The above operation turns on illumination regardless of the current auto light switch setting.
About the Auto Light Switch
Turning on the auto light switch causes the face to illuminate, whenever you position your wrist as described below in any mode.
Moving the watch to a position that is parallel to the ground and then tilting it towards you at more than 40 degrees causes illumination to turn on.
•Wear the watch on the outside of your wrist.
Parallel to | More than |
DST indicator
I | I I | II | |
II |
| I | |
I |
| I | I |
I | I I |
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GMT differential value 
: +2.0



:
Minus sign
1.In the Timekeeping Mode, hold down Auntil the GMT differential value starts to flash, which indicates the setting screen.
•The second hand will move at high speed to the 12 o’clock position, where it will stop.
•The GMT differential value indicates the time difference in hours between Greenwich Mean Time and the currently selected time zone.
•The DST indicator indicates that Daylight Saving Time (summer time) is turned on for the currently selected time zone.
2.Use Bto select the time zone you want to use as your Home Time Zone.
•For full details about GMT differential values, see the “Time Zone Table”.
ground | 40° |
Warning!
•Always make sure you are in a safe place whenever you are reading the face of watch using the auto light switch. Be especially careful when running or engaged in any other activity that can result in accident or injury. Also take care that sudden illumination by the auto light switch does not startle or distract others around you.
•When you are wearing the watch, make sure that its auto light switch is turned off before riding a bicycle, or operating a motorcycle or any other motor vehicle. Sudden and unintended operation of the auto light switch can create a distraction, which can result in a traffic accident and serious personal injury.
3.Press Cto move the flashing in the sequence shown below to select other settings.
GMT differential |
| DST |
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| Minutes |
value |
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| (time) | |
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Day
Month
Year
4.When the setting you want to change is flashing, use Bto change it as described below.
Screen | To do this: | Do this: |
| Change the time zone | Use B(+). |
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| Toggle between Daylight Saving Time ( ), | Press B. |
| Standard Time ( ), or Auto DST ( ) |
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| Change the minutes (time) | Use B(+). |
| Change the year |
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| Change the month |
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| Change the day |
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5. Press A to exit the setting screen.
•When you exit the setting screen, the analog hands are adjusted automatically to match the digital time.
•Auto DST (

) can be selected only while +0.0, +1.0, or +2.0 (+1.0, +2.0, or +3.0 while DST is turned on) is selected as the Home Time Zone. For more information, see “Daylight Saving Time (DST)” below.
Daylight Saving Time (DST)
Daylight Saving Time (summer time) advances the time setting by one hour from Standard Time. Remember that not all countries or even local areas use Daylight Saving Time.
The time calibration signals include both Standard Time and DST data. When the auto DST setting is turned on, the watch switches between Standard Time and DST (summer time) automatically in accordance with the signal it receives.
•The auto DST setting can be turned on only while +0.0, +1.0, or +2.0 (+1.0, +2.0, or +3.0 while DST is turned on) is selected as the Home Time Zone.
•If you experience problems receiving the time calibration signal in your area, it is probably best to switch between Standard Time and Daylight Saving Time (summer time) manually.
To change the Daylight Saving Time (summer time) setting
1.In the Timekeeping Mode, hold down Auntil the GMT differential value starts to flash, which indicates the setting screen.
2.Press C to display the DST setting screen.
3.Press B to cycle through the DST settings in the sequence shown below.
Auto DST ( ) |
| DST off ( ) |
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| DST on ( ) |
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4. Press A to exit the setting screen.
•The DST indicator appears on the display to indicate that Daylight Saving Time is turned on.
•Turning on DST causes the GMT differential value to be increased by one.
To turn the auto light switch on and off
In the Timekeeping Mode (except when a setting screen is on the display), hold down
Bfor about three seconds to toggle the auto light switch on and off.
•Turning on the auto light switch will cause the watch to beep. The ON indicator will appear and the light will turn on for about one second.
•Turning off the auto light switch will cause the watch to beep. The OFF indicator will appear for about one second. The light will not turn on.
•In order to protect against running down the battery, the auto light switch turns off automatically approximately six hours after you turn it on.
Reference
This section contains more detailed and technical information about watch operation. It also contains important precautions and notes about the various features and functions of this watch.
Auto Return Features
•If you leave the watch in the Alarm or Hand Setting Mode for two or three minutes without performing any operation, it returns to the Timekeeping Mode automatically.
•If you do not perform any operation for about two or three minutes while a setting mode is selected, the watch will exit the setting mode automatically.
Scrolling
•The B button is used to change the hand setting in various setting modes. In most cases, holding down this button will start
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-One complete cycle for the hands is one revolution (360 degrees) or 24 hours.
Radio-controlled Atomic Timekeeping Precautions
•Strong electrostatic charge can result in the wrong time being set.
•The time calibration signal bounces off the ionosphere. Because of this, such factors as changes in the reflectivity of the ionosphere, as well as movement of the ionosphere to higher altitudes due to seasonal atmospheric changes or the time of day may change the reception range of the signal and make reception temporarily impossible.
•Even if the time calibration signal is received properly, certain conditions can cause the time setting to be off by up to one second.
•The current time setting in accordance with the time calibration signal takes priority over any time settings you make manually.
•The watch is designed to update the date and day of the week automatically for the period January 1, 2001 to December 31, 2099. Setting of the date by the time calibration signal cannot be performed starting from January 1, 2100.
•This watch can receive signals that differentiate between leap years and
•Though this watch is designed to receive both time data (hour, minutes, seconds) and date data (year, month, day), certain signal conditions can limit reception to time data only.
•If you are in an area where proper time calibration signal reception is impossible, the watch keeps time within ±20 seconds a month at normal temperature.
•If you have problems with proper time calibration signal reception or if the time setting is wrong after signal reception, check your current time zone, and DST (summer time).
Transmitters
This watch is designed to receive the time calibration signal transmitted from Mainflingen, Germany and the signal from Rugby, England. You can configure the watch to select the transmitter that has the strongest signal automatically.
In this case: | The watch does this: |
The first signal auto search operation | 1. Checks the Mainflingen signal first. |
after factory default settings are in effect, | 2. If the Mainflingen signal cannot be |
or after the time zone has been changed | received, checks the Rugby signal. |
Any case other than the above. | 1. Checks the last successfully received |
| signal first. |
| 2. If the last successfully received signal |
| cannot be received, checks the other |
| signal. |
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