Illumination; To Turn On Illumination Manually; To Change The Illumination Duration; To Turn The Auto Light Switch On And Off - Casio 5231 Operation Manual

Operation Guide 5231

Illumination

The face of the watch is illuminated for easy reading in
the dark.
The watch's auto light switch turns on illumination
automatically when you angle the watch towards your
face.
The auto light switch must be turned on (page E-54) for
it to operate.

To turn on illumination manually

Press B in any mode to illuminate the face of the watch.
You can use the procedure below to select either
1.5 seconds or three seconds as the illumination
duration. When you press B, the face will remain
illuminated for about 1.5 seconds or three seconds,
depending on the current illumination duration setting.
E-50
4. After all of the settings are the way you want, press
Exiting a setting mode will normally cause the hands to return to regular
timekeeping automatically. However, if you manually move the hands (page
E-61) and then enter a setting mode, they will not return to regular timekeeping
automatically when you exit the setting mode. In this case, you will need to
return the hands to their normal positions manually (page E-62).
About the Auto Light Switch
Turning on the auto light switch causes illumination
to turn on, 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 more
than 40 degrees causes illumination to turn on.
E-52

To turn the auto light switch on and off

In the Timekeeping Mode, hold down B for about
three seconds to toggle the auto light switch on
(indicator displayed in the right digital dial) and off
(indicator not displayed).
The auto light switch on indicator appears in all
modes while the auto light switch is turned on.
The auto light switch turns off automatically whenever
battery power drops to Level 4 (page E-15).
Auto light switch on indicator
Illumination Precautions
LED panel that provides illumination loses power after very long use.
Illumination may be hard to see when viewed under direct sunlight.
Illumination turns off automatically whenever an alarm sounds.
Frequent use of illumination runs down the battery.
E-54
You may notice a very faint clicking sound coming from the watch when it is
shaken back and forth. This sound is caused by mechanical operation of the auto
light switch, and does not indicate a problem with the watch.
E-56
The watch will return to regular timekeeping automatically if you do not perform
any operation for about two or three minutes. Any changes you have made to
settings up to that point will be saved.
If the hour and minute hands are all at 12 o'clock, which is their home position,
jump to step 3.
D (+) and B (–) to adjust the hour and minute hand positions.
2. Use
Holding down either button will cause the hand to move at high speed. Once
started, high-speed hand movement will continue even if you release the button.
To stop high-speed hand movement, press any button.
High-speed hand movement started with the D (+) button will stop
automatically after 12 revolutions of the minute hand. If started with the B (–)
button, it will stop after one revolution of the minute hand.
A to exit home position correction and return to regular timekeeping.
3. Press
E-58

To change the illumination duration

1.
2.
3.
A to exit the setting mode.
Warning!
More than
40°
Note
Wear the watch on the
outside of your wrist
Auto light switch precautions

Hand Home Position Adjustment

Strong magnetism or impact can cause the hands of the watch to be off.

To adjust home positions manually

1.
Note
After performing home position adjustment, enter the Timekeeping Mode and check
to make sure that the analog hands and the digital dial indicate the same time. If
they do not, perform home position adjustment again.
The above operation turns on illumination regardless of the current auto light switch
setting.
A for about two seconds until ADJ
In the Timekeeping Mode, hold down
appears in the right digital dial.
When you release A, the city code and city name will scroll across the right
digital dial. This is the setting mode.
Whenever you enter a setting mode, the analog hands will automatically move to
positions that allow easier viewing of the digital dials.
C to cycle through the settings in the right digital dial until the current
Use
illumination duration (LT1 or LT3) is shown.
See the sequence in step 2 of the procedure under "To change the current
time and date settings" (page E-31) for information about how to scroll through
setting mode.
D to toggle the illumination duration between three seconds (LT3
Press
displayed) and 1.5 seconds (LT1 displayed).
Always make sure you are in a safe place whenever you are reading the
face of the 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 on 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 traffi c accident and serious
personal injury.
This watch features a "LED", so the auto light switch operates only when available
light is below a certain level. It does not illuminate the face under bright light.
Wearing the watch on the inside of your wrist, movement of your arm, or vibration
of your arm can cause frequent activation of the auto light switch and illumination
of the face. To avoid running down the battery, turn off the auto light switch
whenever engaging in activities that might cause frequent illumination of the face.
Note that wearing the watch under your sleeve while the auto light switch is turned
on can cause frequent illumination of the face and can run down the battery.
Illumination may not turn on if the face of the watch is more than
15 degrees above or below parallel. Make sure that the back of
your hand is parallel to the ground.
Illumination turns off after the preset illumination duration (page
E-51), even if you keep the watch pointed towards your face.
Static electricity or magnetic force can interfere with proper
operation of the auto light switch. If illumination does not turn on,
try moving the watch back to the starting position (parallel with the
ground) and then tilt it back towards your face again. If this does
not work, drop your arm all the way down so it hangs at your side,
and then bring it back up again.
Home position adjustment is not necessary when the analog time and digital time
are the same time in the Timekeeping Mode.
A and keep it depressed for about fi ve
In the Timekeeping Mode, hold down
seconds until H.SET appears in the right digital dial.
The hour and minute hands should all move to 12 o'clock, which is their home
position.
Though ADJ will appear in the right digital dial about two seconds after you hold
down A, do not release the button yet. Keep it depressed until H.SET appears.
When H.SET appears in the right digital dial, release the A button. This will
cause the hour and minute hands to move to 12 o'clock.
E-51
E-53
E-55
E-57
E-59