-2.11-
2.11 Alarms
2.11.1 CPA/TCPA alarm
Visual and audible alarms are generated when the predicted CPA and TCPA of any target become
less than their preset limits.
The ATA continuously monitors the predicted range at the Closest Point of Approach (CPA) and
predicted time to CPA (TCPA) of each tracked target to own ship.
When the predicted CPA of any target becomes smaller than a preset CPA alarm range and its
predicted TCPA less than a preset TCPA alarm limit, the ATA releases an audible alarm. In
addition, the target plot symbol changes to a triangle and flashes together with its vector.
Provided that this feature is used correctly, it will help prevent the risk of collision by alerting you to
threatening targets. It is important that GAIN, A/C SEA, A/C RAIN and other radar controls are
properly adjusted and the ATA is set up so that it can track targets effectively.
CPA/TCPA alarm ranges must be set up properly taking into consideration the size, tonnage,
speed, turning performance and other characteristics of own ship.
The CPA/TCPA alarm feature should never be relied upon as a sole means for detecting the risk of
collision. The navigator is not relieved of the responsibility to keep visual lookout for avoiding
collisions, whether or not the radar or other plotting aid is in use.
Follow the steps shown below to set the CPA/TCPA alarm ranges:
1. Press [MENU], [7], [7] to display the PLOT menu.
2. Press [5] (CPA SET) to select CPA limit desired from the CPA SET line.
3. Press the [ENTER/SELECT] key.
4. Press [6] (TCPA SET) to select a TCPA limit desired.
5. Press the [ENTER/SELECT] key.
6. Press the [MENU] key to close the menu.
Silencing CPA/TCPA audible alarm
Press the [AUDIO OFF] key to acknowledge and silence the CPA/TCPA audible alarm.
The flashing of the triangle plot symbol and vector remain on the screen until the dangerous
situation is no longer present or you intentionally terminate tracking of the target by using the
[CANCEL/CLEAR] key.
2.11.2 Lost target alarm
When the system detects a lost target, tracking on the target is discontinued and the target symbol
becomes a flashing diamond, finally disappearing from the display. The normal plotting symbol is
restored to the target when the target is manually acquired.
Confirming lost target
1. Place cursor on target.
2. Press the [CANCEL/CLEAR] key.
