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NT UF 811 CO GB (c) / March 2014
5.4.10 "Echo Display" menu
Please note: The "Echo Display" mode blocks the measurement function. The measurement values are no
longer calculated, the logger no longer records data.
This mode is used to view the acoustic signal of each chord, which is of use during the commissioning or
maintenance phase, or for example:
 to check the connection of the probes and their good working order,
 to check that the probes are placed at the correct distance,
 to find the origin of a measurement incident (clogging of the probes, obstruction of the structure
between the probes, unforeseen pollution, rupture of a probe cable, etc.).
Comment: Various characteristic signals are analysed in Appendix 1.
"Echo Analysis" mode includes two screens per chord:
 The first displays the acoustic signal between the emission (for short travel times) and the echo
analysis zone. This screen is called the "landscape" display:
Comment: If no acoustic signal reaches the expected zone (for example if one of the probes is not
connected, or if one of the probe cables is damaged), the screen displays a "!" sign in place of the
acoustic signal.
 The second screen shows a zoom on the echo chosen for the measurement. This screen is called the
"zoom display":
o
The two dashed vertical lines give the zone in which the
echo is expected. An echo received outside of this zone is
not taken into account.
o
The dotted vertical line gives the measuring point on the
echo.
o
The number of the chord is indicated below the graph.
o
In the top left hand corner of the screen, the gain applied to
the echo and the sound path duration are shown.
o
The horizontal bar continues to indicate the noise level.
o
The dotted vertical bar marks the place where the travel
time is measured. Absence of this bar means that no
measurement is taken (for example if there is too much
disturbance).
o
The dashed horizontal bar indicates the measurement
threshold. The measurement is taken the first time the
alternation that crosses this threshold reaches 0.
o
The ultrasound path duration delta is indicated in the
bottom left hand corner (not taking into account the
∆ T0).