Nexus 21 NX2 - Manual (Page 26)

SERVER
With a the built in fault finding LED’s, you can check that the signals from channel A
and B are correct. The LED is flashing very fast with 13HZ (13 times per second) which
is difficult to see but you will se that the LED is not on constantly. If one or both LED
are on or of all the time, check the connections.
Irregular values: Check the compass damping (see instrument manual),
Make sure there are no ferrous items close to the transducer.
3. Wind: No reading ( --- )
− C76 should be OFF, if no NMEA wind is connected.
− If inaccurate wind data is received, check the connections (separate through deck
connection or below decks connection), are properly made.
− With a the built in fault finding LED’s, you can check that the signals from channel A
and B are correct. The two LED is flashing once every turn the propeller makes. If
the wind speed is high, the flashing is very fast which is difficult to see but you will
se that the LED is not on constantly.
− If one or both LED are on or of all the time, check the connections.
4. What you should know about digital depth sounders.
The principle of a depth sounder is that you measure the time it takes for a short
acoustic signal to go from the transducer to bottom and back again to the transducer.
The echo changes due to bottom character, heavy layers of salt and temperature,
irregular bottom vegetation, fish etc. Thanks to an advanced signal treatment, these
variations will normally not influence the depth measurement.
You can in some circumstances get transitory disturbances.
Below are listed some explanations for disturbances to the measurement of depth and
how it is expressed on the instrument display.
1. There is no depth reading on the display. Only ( --- ) is displayed:
If there are no depth echoes for 3 seconds, the display indicates 3 dotted lines ( --- )
until a new echo is received.
•
In deep water outside the range of the transducer, or the combination of deep water
and soft bottom which makes it difficult to reflect the signal.
• When the boat is heeling heavily, for example when sailing.
• In a propeller stream, where air bubbles are created. Example when powering
astern or when following close behind a power boat.
• Check the connection at the Server. Make sure the cable is correct between,
instrument and transducer, as marked on the Server.
• Internal mount with poor signal penetration due to a too thick hull, (maximum
thickness recommended is 20 - 30 mm) or air between transducer and hull.
The built in fault finding LED is flashing every time a echo is received to the server. The
depth sounder is transmitting three times per second and the LED flashes 3times/sec if
everything is correct.
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