Operation Manual

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5-20
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If either the CPA LIMIT or TCPA LIMIT is set to zero, then the
dangerous target alarm will not operate.
Since these alarms may include some errors depENTing on the
target tracking conditions, the navigation officer himself should
make the final decision for ship operations such as collision
avoidance.
CAUTION
5.7 ALARM DISPLAY
The ARPA system provides the following alarms:
Dangerous target alarm: CPA/TCPA
Guard zone intrusion alarm: GZ
Lost target alarm: LOST
System function alarm: ARPA (DATA)
Gyro set alarm: SET GYRO
Dangerous Target Alarm: (CPA/TCPA)･･･････････････････････
In the ARPA system, targets are categorized into two types: tracked targets and
dangerous targets. The degree of danger can easily be recognized on the display at a
glance, so that an officer can easily decide to which target he should pay attention.
The types of targets and alarms are shown below.
Dangerous Target Alarm
Status
Symbol on
CRT
Alarm
characters
Alarm sound Conditions
Tracking
target
○ (OFF) (OFF)
• CPA>CPA LIMIT
• 0>TCPA
• TCPA>TCPA LIMIT
Dangerous
target
△
CPA/
TCPA
Beeping
(pee-poh)
Acknowledgeable
• CPA≤
CPA LIMIT
0≤
TCPA≤TCPA LIMIT
CPA LIMIT and TCPA LIMIT: The setting values