Parameter reference
SITRANS LR250 with FOUNDATION FIELDBUS
136
Operating Instructions, 09/2021, A5E32221411-AH
Echo Strength (2.5.9.2.)
Displays the absolute strength (in dB above 1 μV rms) of the echo selected as the
measurement echo.
Values
(view only)
Range:
–20
to
99
TVT (Auto False Echo Suppression) Setup (2.5.10.)
Note
•
Make sure material level is below all known obstructions when Auto False Echo
Suppression is used to learn the echo profile. (An empty
or almost empty vessel is recommended.)
•
Note the distance to material level when Auto False Echo learns the environment. Set
Auto False Echo Suppression Range to a shorter
distance to avoid the material echo being screened out.
•
Set Auto False Echo Suppression and Auto False Echo Suppression Range during startup, if
possible.
•
If the vessel contains an agitator it should be running.
•
Before adjusting these parameters, rotate the instrument for best signal (lower false-echo
amplitude).
Auto False Echo Suppression (2.5.10.1.)
Used together with
Auto False Echo Suppression Range (2.5.10.2.)
to screen out false
echoes in a vessel with known obstructions. A ’learned TVT’ (time varying threshold) replaces
the default TVT over a specified range. See
Auto False Echo Suppression (Page 238) for a
more detailed explanation.