Operational Warnings - Furuno FR-2105 Operator's Manual

9. Press the [1] key followed by the PLOT MENU key to close the ARPA 1 menu.
The guard zone like an example below appears on the display. Note that the guard zone has a
fixed radial extension (width) of 0.5 nm. The label GZ is displayed in the box at the
upper-right on the screen when guard zone is enabled.
A
Target in a guard zone is
marked by inverted flashing
triangle whichever is heading.
Deactivating the guard zone
1. Press the PLOT MENU key to show the ARPA 1 menu.
2. Press the [4] key to select menu item GUARD ZONE.
3. Further press the [4] key to select (or highlight) OFF to deactivate the guard zone.
4. Press the ENTER key to conclude your selection followed by the PLOT MENU key to
close the menu.
To acknowledge the guard zone alarm
Press the AUDIO OFF key to acknowledge and silence the guard zone aural alarm.

2.15 Operational Warnings

There are six main situations which cause the ARPA to trigger visual and aural alarms:
• CPA/TCPA alarm
• Guard zone alarm
• Lost target alarm
• Target full alarm for manual acquisition
• Target full alarm for automatic acquisition
• System failures
CPA/TCPA alarm
Visual and aural alarms are generated when the predicted CPA and TCPA of any target
become less than their preset limits. Press the AUDIO OFF key to acknowledge and silence
the CPA/TCPA aural alarm.
0.5nm
NO. 1 Guard Zone (GZ) is available between 3 and 6 nm with a fixed
B
range depth of 0.5 nm. NO. 2 GZ may be set anywhere when the NO.
1 GZ is valid.
Two more alarm zones (NO. 1 and NO. 2 Target Alarm Zones = TAZ)
may be added in addition. This means a maximum 4 alarm zones are
available at a time. ARPA symbols are not changed to inverted
triangles in the TAZ, only those in GZ do so.
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