User's Manual

Page 130 SITRANS LR250 (HART) – INSTRUCTION MANUAL 7ML19985JE03
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D: Technical Reference
Auto False Echo Suppression (2.8.7.1.)
Auto False Echo Suppression is designed to learn a specific environment (for example, a
particular vessel with known obstructions), and in conjunction with Auto False Echo
Suppression Range to remove false echoes appearing in front of the material echo.
The material level should be below all known obstructions at the moment when Auto
False Echo Suppression learns the echo profile. Ideally the vessel should be empty or
almost empty, and if an agitator is present, it should be running.
The device learns the echo profile over the whole measurement range and the TVT is
shaped around all echoes present at that moment.
Auto False Echo Suppression Range (2.8.7.2.)
Auto False Echo Suppression Range specifies the range within which the learned TVT is
applied. Default TVT is applied over the remainder of the range.
The learned TVT screens out the false echoes caused by obstructions. The default TVT
allows the material echo to rise above it.
Auto False Echo Suppression Range must be set to a distance shorter than the distance
to the material level when the environment was learned, to avoid the material echo being
screened out.
Notes:
• For detailed instructions on using this feature via PDM see Auto False Echo
Suppression
on page 52.
• For detailed instructions on using this feature via the handheld programmer see
Auto False Echo Suppression (2.8.7.1.) on page 94.
High Cal. Pt.
= 0
obstruction
at 1.3 m
material
level at
3.2 m
false
echo
material
echo
default
TVT
sensor reference point
Example before Auto False Echo Suppression