Furuno FAR-28x7 Series - Manual (Page 178)

4. AIS OPERATION
4-14
4.10 Lost Target
A target is declared a lost target when it fails to produce data for six minutes or
five reporting intervals, whichever is the shorter. When this occurs, the target is
marked with the (flashing) lost target symbol and the indication “LOST” appears.
To acknowledge a lost target, press the [ALARM ACK] key or roll the trackball to
choose the ALARM ACK box and then push the left button.
Lost target
Note 1: If an ARP lost target mark is displayed when the [ALARM ACK] key is
pressed (or the ALARM ACK box is clicked) to acknowledge an AIS lost
target, the ARP lost target will also be erased.
Note 2: The AIS data transmission interval depends on target’s speed. For
example, the data is transmitted every 10 seconds on ship speed of 0 to
14 kt and every two seconds on the ship speed of more than 23 knots.
For details see the owner’s manual of the AIS.
You may choose what lost targets to sound the lost target alarm against as
follows:
1. Roll the trackball to choose the MENU box and then push the left button.
2. Roll the wheel to choose 4 ARP•AIS and then push the wheel or the left
button.
3. Roll the wheel to choose 9 AIS LOST ALARM and then push the wheel or left
button.
4. Choose ACTIVATED TARGET, ALL TARGET or RANGE as appropriate and
then push the wheel. For range, choose the range within which to sound the
lost target alarm. For example, setting “5 nm” will sound the alarm against
any lost target within 5 nm of own ship.
5. Push the right button several times to close the menu.