NorthStar Navigation Echo Sounder NorthStar 491 - Manual (Page 60)

Page 56 491 Echo Sounder Operations Manual
Understanding the alarms
The echo sounder’s alarms work just like the other alarms.
Their status is updated every second, and their messages are
displayed in the following ways:
• at the bottom of the ECHO screen, and also on various
windows that may be overlaid onto these screens
• on the ALARMS screen
On this screen, you can manually “clear,” or stop, new alarms,
although some are auto-clearing, and you can view old alarms,
which are alarms that already have cleared.
To alert you automatically in situations related to echo
sounding, you can set three alarms:
• fish alarm
• seabed bottom alarm
• temperature alarm
NOTE:
You also can set the echo sounder to automatically save *FISH##*
or *THERM##* waypoints, when fish or a certain temperature are
detected, if the fish or temperature alarms are on. To automatically
save these waypoints, see ”Number of special waypoints” starting
on page 2-14.
Setting the fish alarm
When the fish alarm is on, an alarm sounds if an echo returns
from either inside or outside specific upper and lower limits
you’ve set.
To set the fish alarm:
1. At the ECHO screen, press MORE.
2. Press ALARM.
3. At the ALARM screen, press FISH ALARM.
The options on the FISH ALARM window are on/off, echo
strength level, upper and lower marker depths, and inside
or outside markers.