User's Manual

7ML19985LT01 SITRANS LR560 (PROFIBUS PA) – OPERATING INSTRUCTIONS Page 119
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D: Technical Reference
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 (2.4.8.2.)
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.
High Cal. Pt.
= 1 m
obstruction
at 13 m
material
level at 31 m
false
echo
material
echo
default
TVT
sensor
reference
point
Example before Auto False Echo Suppression
Low Cal. Pt.
= 45 m
Example after Auto False Echo Suppression
learned
TVT
material
echo
false echo
echo
marker
Auto False Echo
Suppression
Range set to 20 m
Auto False Echo
Suppression Range
default TVT