CASIO PRT40C-1
Owner's Manual

To recall data from memory
Magnetic north indicator Direction
A

To perform bidirectional calibration
A B

Date
B

While in the Digital Compass Mode, use D to scroll through the data in the following sequence.
Normal Display Memory 5 Memory 1 Memory 2

A

S

1. While in the Digital Compass Mode (Normal Display), hold down A until the upper display changes to show ��1��. � At this time, the magnetic north indicator flashes at the 12 o�clock position to indicate that the watch is ready to calibrate the first direction. 2. Place the watch on a level surface, and press B to calibrate the first direction. � When the calibration procedure is complete, the message �OK� appears in the upper display. This soon changes to ��2�� and the magnetic north indicator flashes at the 6 o�clock position to indicate that the watch is ready for the second direction.

Memory 4

Memory 3

BEARING

C
P
A S

D E

BEARING

To delete data
D

C

E

Time Direction value Memory No.

1. While in the Digital Compass Mode, scroll through the data items and display the one you want to delete. 2. Hold down A until the displayed value changes to �� � ��.

� Holding down A causes the message �CLR� to appear on the display, followed by the value changing to �� � ��.

Digital Compass Precautions
This watch features a built-in magnetic bearing sensor that detects terrestrial magnetism. This means that the northern direction indicated by this watch is magnetic north, which is somewhat different from true polar north. The magnetic north pole is located in northern Canada, while the magnetic south pole is in southern Australia. Note that the difference between magnetic north and true north as measured with all magnetic compasses tends to be greater as one gets closer to either of the magnetic poles. You should also remember that some maps indicate true north (instead of magnetic north), and so you should make allowances when using such maps with this watch.

3. Rotate the watch 180 degrees. 4. Press B again to calibrate the second direction. � When the calibration procedure is complete, the message �OK� appears in the upper display. After a short while, the watch automatically returns to the Digital Compass Mode.

Precautions about bidirectional calibration
� You can use any two opposing directions for bidirectional calibration. You must, however, make sure that they are 180 degrees opposite each other. Remember that if you perform the procedure incorrectly, you will get wrong readings from the Digital Compass. � Do not move the watch during the one or two seconds (from the point you press B up to the point that �OK� appears in the upper display) that the calibration of each direction is in progress. If you do, the message �ERR� appears in the upper display. When this happens, restart the bidirectional calibration procedure from the beginning. � The appearance of �ERR� during bidirectional calibration can also be caused by local interference. If you suspect that this is the case, move to another location and try the procedure again. � You should perform bidirectional calibration in an environment that is the same as that where you plan to be using the Digital Compass. If you plan to use it in an open field, for example, calibrate in an open field.

Location
� Using the Digital Compass when you are near a source of strong magnetism can cause large errors in types of objects: permanent magnets (magnetic necklaces, etc.), concentrations of metal (metal doors, lockers, etc.), high tension wires, aerial wires, household appliances (TVs, personal computers, washing machines, freezers, etc.) � Accurate direction measurements are impossible while in a train, boat, air plane, etc. � Accurate measurements are also impossible indoors, especially inside ferroconcrete structures. This is because the metal framework of such structures picks up magnetism from appliances, etc. readings. Because of this, you should avoid using the Digital Compass while in the vicinity of the following

To perform northerly calibration
A B

1. While in the Digital Compass Mode (Normal Display), hold down A until the upper display changes to show ��1��. 2. Press C to start the northerly calibration procedure. � At this time, the indicator �N� appears in the upper display. 3. Place the watch on a level surface, and position it so that its 12 o�clock position points north (as measured with another compass). 4. Press B to start the calibration operation.

A

S

BEARING

Storage
� The precision of the compass may deteriorate if the watch becomes magnetized. Because of this, you should be sure to store the watch away from magnets or any other sources of strong magnetism, including: permanent magnets (magnetic necklaces, etc.) and household appliances (TVs, personal computers, washing machines, freezers, etc.) � Whenever you suspect that the watch may have become magnetized, perform one of the calibration procedures under �Calibrating the Digital Compass�.
C E D

� When the calibration procedure is complete, the message �OK� appears in the upper display. After a short while, the watch automatically returns to the Digital Compass Mode.

Calibrating the Digital Compass
Whenever you suspect that the readings produced by the Digital Compass are wrong, you should calibrate it. You can use either one of two calibration procedures: bidirectional calibration or northerly calibration. You should use bidirectional calibration when you want to calibrate the Digital Compass to operate within an area exposed to magnetic force. This type of calibration should be used if the watch become magnetized for any reason. With northerly calibration, you �teach� the watch which way is north (which you have to determine with another compass or some other means). You could use this calibration procedure, for example, to set the watch to indicate true north instead of magnetic north.

ALTIMETER FUNCTIONS
A built-in altimeter uses a pressure sensor to detect the current air pressure which is then used to estimate the current altitude in accordance with ISA (International Standard Atmosphere) values for altitude and air pressure. If you preset a reference altitude, the watch will also calculate the current relative altitude based on your preset value. Altimeter functions also include data storage memory and an altitude alarm.

Important!
� This watch estimates altitude based on air pressure. This means that altitude readings for the same location may vary if air pressure changes. � Sudden changes in the weather make it impossible to produce accurate altitude readings. � This watch employs a semiconductor pressure sensor, which is affected by temperature changes. When taking altitude measurements, be sure to do so while ensuring that the watch is not exposed to temperature changes. � Do not use this watch while participating in sports where there are sudden altitude changes. Also, do not use this watch for applications that demand professional or industrial level precision. This watch should not be used while engaging in the following activities: sky diving, hang gliding, paragliding, gyrocopter riding, glider riding, etc.

Important!
� If you want to perform both bidirectional and northerly calibration, be sure to perform bidirectional calibration first, and then perform northerly calibration. This is necessary because bidirectional calibration cancels any previously set northerly calibration setting. � If you do not perform any button operation for two or three minutes while either calibration procedure is in progress (while the magnetic north indicator is flashing at the 12 or 6 o�clock position), the watch automatically returns to the Digital Compass Mode. � The more correctly you perform bidirectional calibration, the better the accuracy of your Digital Compass readouts. You should perform bidirectional calibration whenever you change environments where you use the Digital Compass, and whenever you feel that the Digital Compass is producing incorrect readings.

�5�