Echo Lock; Echo Position Detection; Auto False Echo Suppression - Siemens SITRANS LR260 Operating Instructions Manual

A.3.3

Echo Lock

If the echo selected by Algorithm is within the Echo Lock window, the window is centered about
the echo, which is used to derive the measurement.
● Lock Off: SITRANS LR260 responds immediately to a new selected echo (within the
restrictions set by the Maximum Fill / Empty Rate), but measurement reliability is affected.
A.3.4

Echo Position Detection

The echo position algorithm (2.2.4.1.2. Echo Position) determines which point on the echo will
be used to calculate the precise time of flight, and calculates the range using the calibrated
propagation velocity (adjusted by a propagation factor, if necessary).
The options are Center, CLEF (Constrained Leading Edge Fit), Hybrid or Rising Edge. CLEF
uses the leading edge of the echo. It can be used to compensate for materials with a low dK
value, which may cause the vessel bottom to be reported as the level instead of the actual
material level, in low level conditions.
Hybrid uses a combination of Center and CLEF, depending on the setting for CLEF range.
CLEF range is the level below which the CLEF algorithm will be used: above this level the
Center algorithm is used.
A.3.5

Auto False Echo Suppression

Note
● For detailed instructions on using this feature via PDM see Auto False Echo Suppression
(Page 87).
● For detailed instructions on using this feature via the handheld programmer see Auto False
Echo Suppression (AUTO ECHO SUPP) (2.2.4.3.)
Auto False Echo Suppression is designed to learn a specific environment (for example, a
particular vessel with known obstructions), and in conjunction with Auto False Echo
Suppression Range to remove false echoes appearing in front of the material echo.
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 (AUTO ECHO SUPP) (2.2.4.3.)
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.
SITRANS LR260 with mA/HART
Operating Instructions, 11/2019, A5E32337683-AD
Appendix A: Technical reference
A.3 Echo Processing
153