Echo Selection - Siemens SITRANS L Operating Instructions Manual

Technical reference
C.3 Echo processing
C.3.2

Echo selection

Time varying threshold (TVT)
A time varying threshold (TVT) hovers above the echo profile to screen out unwanted
reflections (false echoes).
In most cases the material echo is the only one which rises above the default TVT.
In a vessel with obstructions, a false echo may occur. See Auto False Echo Suppression
(Page 182) for more details.
①
②
③
④
The device characterizes all echoes that rise above the TVT as potential good echoes. Each
peak is assigned a rating based on its strength, area, height above the TVT, and reliability,
amongst other characteristics.
Algorithm (2.5.7.1.)
The true echo is selected based on the setting for the Echo selection algorithm. Options are
true First Echo, Largest Echo, or best of First and Largest.
178
Default TVT
Echo profile
Material level
Echo marker
SITRANS LR200 with PROFIBUS PA
Operating Instructions, 07/2021, A5E32337680-AF