E-8
Checking the Current Time in a Different Time Zone ………………………………………………… E-90
To enter the World Time Mode …………………………………………………………………… E-90
To view the time in another time zone …………………………………………………………… E-90
To specify standard time or daylight saving time (DST) for a city ……………………………… E-91
Illumination ………………………………………………………………………………………………… E-92
To turn on illumination manually …………………………………………………………………… E-92
To change the illumination duration ……………………………………………………………… E-92
To turn the auto light switch on and off …………………………………………………………… E-94
Other Settings ……………………………………………………………………………………………… E-96
To turn the button operation tone on and off ……………………………………………………… E-96
To turn Power Saving on or off …………………………………………………………………… E-97
Troubleshooting …………………………………………………………………………………………… E-98
Specifi cations ……………………………………………………………………………………………… E-105
E-9
Charging the Watch
The face of the watch is a solar panel that generates power from light. The generated power charges a
built-in rechargeable battery, which powers watch operations. The watch charges whenever it is exposed
to light.
Charging Guide
Whenever you are not wearing the
watch, leave it in a location where it
is exposed to light.
• Best charging performance is
achieved by exposing the watch to
the strongest light available.
When wearing the watch, make sure
that its face is not blocked from light
by the sleeve of your clothing.
• The watch may enter a sleep state
(page E-13) if its face is blocked
by your sleeve even only partially.
Warning!
Leaving the watch in bright light for charging can cause it to become quite hot.
Take care when handling the watch to avoid burn injury. The watch can become particularly hot
when exposed to the following conditions for long periods.
• On the dashboard of a car parked in direct sunlight
• Too close to an incandescent lamp
• Under direct sunlight
E-10
Important!
• Allowing the watch to become very hot can cause its liquid crystal display to black out. The
appearance of the LCD should become normal again when the watch returns to a lower temperature.
• Turn on the watch’s Power Saving function (page E-13) and keep it in an area normally exposed to
bright light when storing it for long periods. This helps to ensure that power does not run down.
• Storing the watch for long periods in an area where there is no light or wearing it in such a way that it is
blocked from exposure to light can cause power to run down. Expose the watch to bright light
whenever possible.
Power Levels
You can get an idea of the watch’s power level by observing the battery power indicator on the display.
Level Battery Power Indicator Function Status
1
(H)
All functions enabled.
2
(M)
All functions enabled.
3
(L)
l
Auto and manual receive, illumination,
beeper, and sensor operation disabled.
Battery power
indicator
Battery power
indicator
E-11
Level Battery Power Indicator Function Status
4
(CHG)
Except for the current time and the
CHG
(charge) indicator, all functions and display
indicators disabled.
5 – – – All functions disabled.
• The fl ashing
LOW
indicator at Level 3 (
L
) tells you that battery power is very low, and that exposure to
bright light for charging is required as soon as possible.
• At Level 5, all functions are disabled and settings return to their initial factory defaults. Once the battery
reaches Level 2 (
M
) after falling to Level 5, reconfi gure the current time, date, and other settings.
• Display indicators reappear as soon as the battery is charged from Level 5 to Level 2 (
M
).
• Leaving the watch exposed to direct sunlight or some other very strong light source can cause the
battery power indicator to show a reading temporarily that is higher than the actual battery level. The
correct battery level should be indicated after a few minutes.
• All data stored in memory is deleted, and the current time and all other settings return to their initial
factory defaults whenever battery power drops to Level 5 and when you have the battery replaced.
Power Recovery Mode
• Performing multiple sensor, illumination, or beeper operations during a short period may cause all of
the battery power indicators (
H
,
M
, and
L
) to start fl ashing on the display. This indicates that the watch
is in the power recovery mode. Illumination, alarm, countdown timer alarm, hourly time signal, and
sensor operations will be disabled until battery power recovers.
• Battery power will recover in about 15 minutes. At this time, the battery power indicators (
H
,
M
,
L
) will
stop fl ashing. This indicates that the functions listed above are enabled again.
E-12
• If all of the battery power indicators (
H
,
M
,
L
) are fl ashing and the
CHG
(charge) indicator also is
fl ashing, it means the battery level is very low. Expose the watch to bright light as soon as possible.
• Even if battery power is at Level 1 (
H
) or Level 2 (
M
), the Digital Compass Mode, Barometer/
Thermometer Mode, or Altimeter Mode sensor may be disabled if there is not enough voltage available
to power it suffi ciently. This is indicated when all of the battery power indicators (
H
,
M
,
L
) are fl ashing.
• Frequent fl ashing of all of the battery power indicators (
H
,
M
,
L
) probably means that remaining battery
power is low. Leave the watch in bright light to allow it to charge.
Charging Times
Exposure Level (Brightness)
Daily
Operation
*1
Level Change *2
Level 5 Level 4 Level 3 Level 2 Level 1
Outdoor sunlight (50,000 lux) 5 min. 2 hours 14 hours 4 hours
Sunlight through a window (10,000 lux)
24 min. 6 hours 68 hours 19 hours
Daylight through a window on a
cloudy day (5,000 lux)
48 min. 11 hours 138 hours 37 hours
Indoor fl uorescent lighting (500 lux) 8 hours 162 hours – – – – – –
*1 Approximate amount of exposure time required each day to generate enough power for normal daily
operation.
*2 Approximate amount of exposure time (in hours) required to take power from one level to the next.
• The above exposure times all are for reference only. Actual exposure times depend on lighting
conditions.
• For details about the operating time and daily operating conditions, see the “Power Supply” section of
the Specifi cations (page E-108).
E-13
Power Saving
When turned on, Power Saving enters a sleep state automatically whenever the watch is left for a certain
period in an area where it is dark. The table below shows how watch functions are affected by Power
Saving.
• For information about enabling and disabling power saving, see “To turn Power Saving on and off”
(page E-97).
• There actually are two sleep state levels: “display sleep” and “function sleep”.
Elapsed Time in Dark Display Operation
60 to 70 minutes (display sleep) Blank, with
PS
fl ashing Display is off, but all functions are enabled.
6 or 7 days (function sleep) Blank, with
PS
not fl ashing
All functions are disabled, but timekeeping is
maintained.
• The watch will not enter a sleep state between 6:00 AM and 9:59 PM. If the watch is already in a sleep
state when 6:00 AM arrives, however, it will remain in the sleep state.
• The watch will not enter a sleep state while it is in the Stopwatch Mode or Countdown Timer Mode.
To recover from the sleep state
Move the watch to a well-lit area, press any button, or angle the watch towards your face for reading (page
E-93).
E-14
Radio Controlled Atomic Timekeeping
This watch receives a time calibration signal and updates its time setting accordingly. However, when
using the watch outside of areas covered by time calibration signals, you will have to adjust the settings
manually as required. See “Confi guring Current Time and Date Settings Manually” (page E-30) for more
information.
This section explains how the watch updates its time settings when the city code selected as the Home
City is in Japan, North America, Europe, or China, and is one that supports time calibration signal
reception.
If your Home City Code setting is this:
The watch can receive the signal from the transmitter
located here:
LIS, LON, MAD, PAR, ROM, BER, STO, ATH, MOW Anthorn (England), Mainfl ingen (Germany)
HKG, BJS Shangqiu City (China)
TPE, SEL, TYO Fukushima (Japan), Fukuoka/Saga (Japan)
HNL, ANC, YVR, LAX, YEA, DEN, MEX, CHI, NYC, YHZ,
YYT
Fort Collins, Colorado (United States)
Important!
• The areas covered by
MOW
,
HNL
and
ANC
are quite far from the calibration signal transmitters, so
certain conditions may cause reception problems.
• When
HKG
or
BJS
is selected as the Home City, only the time and date are adjusted according to the
time calibration signal. You need to switch manually between standard time and daylight saving time
(DST) if required. See “To confi gure Home City and summer time settings” (page E-28) for information
about how to do this.
E-15
Approximate Reception Ranges
UK and German Signals
Anthorn
500 kilometers
1,500 kilometers
The Anthorn signal is
receivable within this area
Mainflingen
North American Signal
Japanese Signals Chinese Signal
500 kilometers
Changchun
Beijing
Shangqiu
Shanghai
Chengdu
Hong Kong
1,500 kilometers
2,000 miles
(3,000 kilometers)
600 miles
(1,000 kilometers)
Fort Collins
1,000 kilometers
Signals are receivable in the Taiwan area
when reception conditions are
ood.
For the Honolulu and Anchorage time zones, the
signal can be received when reception conditions
are favorable.
Fukuoka/Saga
500 kilometers
Fukushima
Operation Guide 3444
Join the conversation about this product
Here you can share what you think about the Casio Pro Trek PRW-3100YB-1ER Watch. If you have a question, first carefully read the manual. Requesting a manual can be done by using our contact form.