Setting the bottom level
To set the bottom alarm:
1.At the ECHO screen, press MORE.
2.Press ALARM.
3.At the ALARM screen, press BOTTOM ALARM.
The options on the BOTTOM ALARM window are on/off and the depth setting.
Bottom alarm window
You can set the depth level for the seabed, so that as soon as the bottom is shallower than this depth, the bottom alarm will sound.
To set the bottom level, at the BOTTOM ALARM window, press the CURSOR PAD up or down to set the depth, or use the KEYPAD to manually enter the desired depth.
NOTE:
The 491’s depth indicator reflects the depth below your vessel’s transducer, not below the keel. Ask your installer for the exact dis- tance between your transducer and your keel. This value must then always be manually added to the 491’s depth indicator, or else entered into the transducer’s depth setting on the ECHO SOUNDER SETUP screen for an automatically correct reading.
491 Echo Sounder Operations Manual | Page 59 |
