80deptraNX2.doc Page 1 Latest update: 3 Jan -03
8.0 DEPTH TRANSDUCER AND SYSTEM
Principle of operation - Software in the NX2 Server
• Create send-pulses SLP of 0,5uS-2,0mS 3 times per second
• Measure the time between send pulse and returning echo signal.
• If more than one , uses the longest echo
• Calculate the depth to be shown. Based on 0.7m / mSec.
• Calculate the length of the next outgoing SLP
Signal handling
• Every send pulse is formed as burst of high frequency adapted to the
transducer frequency (185 KHz) with high energy 550 Vpp
• The returned echo is amplified, filtered and formed to a digitalized ECHO
signal to be used for depth calculation in the Software.
Transducer
The mounting and position of the transducer is essential to the final result and
capacity of the depth. Internal mounting of the transducer affects the dynamic
performance of the depth system. Therefore, the customer has to make sure of
that the choice of internal mounting works in his boat to full satisfaction.
If not, he has to make a through hull mounting
Trouble tracing
The Depth reading have to be considered as the most delicate measurement
when it comes to Marine Instruments. Not only that the ratio between the weakest
and strongest echo is 1 to 100.000 times but also that a digital Depth sounder
shall decide which one is the bottom echo, of all echoes coming in.
Depth have to cope with widespread conditions of bottoms, heavy water layers of
salt and temperature, boats, mountings, vegetation, fish, disturbances etc. and
the system is expected to all the time show the correct value of the water depth.
The advanced signal treatment in the NX2 Server handles these variations to
minimise influence of the depth measurement.
In some circumstances, however, transitory disturbances can occur.
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