Casio 2531 Operation Manual

MO0404-EC

Getting Acquainted

Congratulations upon your selection of this CASIO watch. To get the most out of your
purchase, be sure to carefully read this manual and keep it on hand for later reference
when necessary.
Expose the watch to bright light to charge its battery before using it.
You can use this watch even as its battery is being charged by exposure to bright
light.
• Be sure to read "Battery" of this manual for important information you need to
know when exposing the watch to bright light.
If the display of the watch is blank...

General Guide

• The illustration below shows which buttons you need to press to navigate between
modes.
• In any mode, press L to illuminate the display.
Bearing Mode

Timekeeping

Moon phase indicator
Tide graph
PM indicator
Day of week
Month – Day
Hour : Minutes Seconds
To set the time and date
Year
Seconds
Power Saving
3. When the setting you want to change is flashing, use D and A to change it as
described below.
To change this setting
Seconds
Hour, Minutes, Year,
Month, Day
12/24-Hour Format
Power Saving
4. Press C twice to exit the setting screen.
• The first press of C displays the GMT differential setting screen. Pressing C again
exits the setting screen.
• See "Power Saving Function" for details about configuring Power Saving settings.
• The 12-hour/24-hour timekeeping format you select in the Timekeeping Mode is
applied in all modes.
• The day of the week is automatically displayed in accordance with the date (year,
month, and day) settings.
Operation Guide 2531
If the SLEEP indicator is on the display, it means that the
display is blank because the watch's Power Saving
function has turned off the display to conserve power.
Power Saving automatically turns off the display and puts
the watch into a sleep state whenever your watch is left for
a certain period where it is dark.
• The initial factory default setting is Power Saving on.
• The watch recovers from the sleep state if you move it to
a well-lit area , if you press any button, or if you angle
*
the watch towards your face for reading.
It can take up to five seconds for the display to turn on.
*
• See "Power Saving Function" for more information.
Timekeeping Mode
Press A.
Press B.
Use the Timekeeping Mode to set and view the current
time and date.
• The tide graph shows tidal movements for the current
date in accordance with the current time as kept in the
Timekeeping Mode.
• The Moon phase indicator shows the current Moon
phase in accordance with the current date as kept in the
Timekeeping Mode.
Important!
• Moon phase, tide graph data, Bearing Mode solar
azimuth data, and Moon/Tide Data Mode data will not
be displayed properly unless the Timekeeping Mode
current date and time settings and Home Site data are
configured correctly. See "Home Site Data" for more
information.
1. In the Timekeeping Mode, hold down C until the
seconds start to flash, which indicates the setting
screen.
2. Press B to move the flashing in the sequence shown
below to select other settings.
Minutes
Hour
Day Month
Perform this button operation
Press D to reset to 00.
Use D (+) and A (–) to change the setting.
Press D to toggle between 12-hour (12H) and
24-hour (24H) timekeeping.
Press D to toggle Power Saving on (ON) and off
(OFF).
• The longitude, lunitidal interval, Moon phase indicator, tide graph data, and solar
azimuth data that appear on the display of this watch are not intended for
navigation purposes. Always use proper instruments and resources to obtain data
for navigation purposes.
• This watch is not an instrument for calculating low tide and high tide times. The
tide graph of this watch is intended to provide a reasonable approximation of tidal
movements only.
• When engaging in mountain climbing or other activities in which losing your way
can create a dangerous or life-threatening situation, always be sure to use a
second compass to confirm direction readings.
• CASIO COMPUTER CO., LTD. assumes no responsibility for any loss, or any
claims by third parties that may arise through the use of this watch.
About This Manual
(Light)
Moon / Tide Data Mode
Press B.
Dual Time Mode

Home Site Data

Moon phase, tide graph data, Bearing Mode solar azimuth data, and Moon/Tide Data
Mode data will not be displayed properly unless Home Site data (GMT differential,
longitude, and lunitidal interval) is configured correctly.
• The GMT differential is the time difference of the time zone where the site is located
from Greenwich Mean Time.
• Note that you must add one hour to the GMT differential for your time zone
whenever you change to Daylight Saving Time. Subtract one hour when you change
back to Standard Time.
• The lunitidal interval is the time elapsing between the Moon's transit over a meridian
and the next high tide at that meridian. See "Lunitidal Interval" for more information.
• This watch displays lunitidal intervals in terms of hours and minutes.
• The "Site Data List" and "Lunitidal Interval List" provide GMT differential, longitude,
and lunitidal interval information around the world.
• The following is the initial factory default Home Site data (Tokyo, Japan) when you
first purchase the watch, whenever battery power drops to Level 5, and whenever
you have the battery replaced. Change these settings to match the area where you
normally use the watch.
GMT differential (+9.0); Longitude (East 140 degrees); Lunitidal interval (5 hours,
20 minutes)
To configure Home Site data
12/24-Hour
Format
GMT differential
Year
4. When the setting you want to change is flashing, use D and A to change it as
described below.
Setting
GMT differential
Longitude
Lunitidal Interval
Hours, Minutes
5. Press C to exit the setting screen.
Warning!
• Button operations are indicated using the letters shown
in the illustration.
• Each section of this manual provides you with the
information you need to perform operations in each
mode. Further details and technical information can be
found in the "Reference" section.
Coutdown Timer Mode
Stopwatch Mode
1. In the Timekeeping Mode, hold down C until the
seconds start to flash, which indicates the setting
screen.
2. Press C again to display the GMT differential setting
screen.
3. Press B to move the flashing in the sequence shown
below to select other settings.
GMT Lunitidal Interval
Longitude
differential Hours
Screen Button Operations
Use D (+) and A (–) to change the setting.
• You can specify a value in the range of –11.0
to +14.0, in 0.5-hour unit.
Use D (+) and A (–) to change the setting.
• You can specify a value in the range of
179°W to 180°E, in 1-degree units.
Use D (+) and A (–) to change the setting.
Alarm Mode
Lunitidal Interval
Minutes
1