Furuno color video plotter GD1720C - Manual (Page 148)

4. VIDEO SOUNDER OPERATION
4-19
Alarm messages
The table below shows the sounder alarm messages and their meanings.
Sounder alarm messages and their meanings
Message Meaning
DEPTH ALARM! Bottom alarm violated.
FISH ALARM! Fish alarm violated.
TEMPERATURE ALARM! Water temperature alarm violated.
4.12 Water Temperature Graph
The water temperature graph (appropriate sensor required) plots water temperature on the
sounder display. (See the figure on page 4-2.) It can be turned on or off as below.
1. Press the MENU key to open the menu.
2. Press the SOUNDER MENU soft key.
3. Select TEMPERATURE GRAPH and press the EDIT soft key.
4. Select OFF (default setting) or ON as appropriate.
5. Press the ENTER soft key.
6. Press the MENU key to close the menu.
4.13 Changing Pulse Repetition Rate
Pulse repetition rate can be changed. Normally, the highest rate (20) is used. When in
shallow waters, second reflection echoes may appear between surface and actual bottom
echo. In this case lower the PRR level. The option “SPD SENSING PRR” means the ship’s
speed dependent mode, where the PRR changes automatically with ship’s speed (required
speed input.) For further information about the ship’s speed dependent mode, see page
4-13.
1. Press the MENU key to open the menu.
2. Press the SOUNDER MENU soft key.
3. Select PRR LEVEL.
4. Press the EDIT soft key to open the setting window.
5. Use the Cursor pad to select the rate for repetition.
6. Press the ENTER soft key followed by the MENU key to close the menu.
Too small setting reduces the number of pulse repetition. This may cause a problem to
search fish schools. Select “20” unless multistage reflections appear on the display.