Algorithm - Siemens SITRANS L 7ML5400 Operating Instructions Manual

Technical reference
A.2 Echo Processing
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.
A.2.1.2

Algorithm

The true echo is selected based on the setting for the Echo selection algorithm. For a list of
options see Algorithm (2.12.2.1.) (Page 224). All algorithms ultimately use confidence to
select the true echo. However, when applications report a low confidence value, the TR
algorithm (which tracks the moving echo) can be used to predict the primary variable.
Algo-
rithm
TF
TR
L
BLF
ALF
296
Default TVT
Echo Profile
Material level
Echo marker
Echo Determination
True First Selects the first echo that
echo crosses TVT curve.
TRacker Selects the echo that is closest
to the transducer, and is mov-
ing. (If echo location is steady,
BLF algorithm should be
used.)
Largest echo
Selects the largest echo above
the TVT curve.
Best of First
Selects the echo (first and
and Largest highest) with the highest
echo confidence value.
Area, Larg- Selects the echo with the
est, and First highest confidence value
based on the three criterion
(widest, highest, and first).
Suggested Usage
Use in liquids applications free of obstruc-
tions when confidence of first echo is high.
Only use TR algorithm in process applica-
tions with continuous level changes, and a
risk of fixed obstructions that could inter-
fere with true level, resulting in low confi-
dence.
Use in long range liquids applications with
large (tall) material return echoes.
Default and most commonly used. Use in
all short to mid range general liquids and
solids applications where there is a rela-
tively large (tall), sharp echo.
Use in mid to long range solids applications
where the material return echo is wide and
large, and where competing smaller ech-
oes challenge BLF.
Operating Instructions, 04/2021, A5E33329501-AG
SITRANS LUT400