Echo Selection; Confidence; Auto False Echo Suppression And Custom Tvt; Echo Selection Algorithms - Siemens SITRANS LR500 Series Operating Instructions Manual

Technical reference
B.2 Echo processing
lock window
9) . If the new echo is outside of the window, it is not accepted until echo lock requirements
are satisfied.
Reform echo (3.3.4.1) (Page 134)
1)
Algorithm (3.3.3.1) (Page 133)
2)
Lower calibration point (2.3.1) (Page 118)
3)
Confidence (3.3.1.1) (Page 132)
4)
B.2.2

Echo selection

B.2.2.1

Confidence

Confidence describes the quality of an echo. It is used internally to select the true echo.
For more information, see Requesting an echo profile (Page 83).
B.2.2.2

Auto false echo suppression and Custom TVT

If you have a vessel with known obstructions, use auto false echo suppression (AFES) to prevent
false echo detection. If the device displays a false high level, or the reading is fluctuating
between the correct level and a false high level, this typically is the result of obstructions in the
vessel.
False echoes can be caused by an obstruction in the sensor signal beam (such as pipes,
ladders, chains). Such false echoes may rise above the default TVT curve.
The device takes a profile for the whole measurement range and the learned TVT is shaped
around all echoes present at that moment.
The AFES parameter Auto false echo suppression (Page 98) specifies the range within
which the learned TVT is applied. The default TVT is applied over the remainder of the
measurement range.
The material level should be below all known obstructions at the moment when the TVT is
learned. Ideally the vessel should be empty or almost empty.
AFES 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.
B.2.2.3

Echo selection algorithms

The echo is selected based on echo selection algorithms that ultimately use confidence to select
the echo.
202
, it is accepted, and displays and outputs are updated per the rate parameters
8)
Custom TVT shaper mode (3.3.6.5)
6)
(Page 137)
Echo lock window (3.3.5.2) (Page 136)
7)
Echo threshold (3.3.3.2) (Page 133)
8)
Fill rate limit (2.2.3) (Page 117) and Echo lock
9)
(3.3.5.1) (Page 135)
SITRANS LR500 series with mA/HART
Operating Instructions, 03/2024, A5E51099898-AA
10)