Siemens 7ML5431 - Page 129

Parameter reference
SITRANS LR250 with mA/HART
Operating Instructions, 10/2019, A5E32220602-AG
129
Echo Select (2.8.4.)
Algorithm (2.8.4.1.)
Selects the algorithm to be applied to the echo profile to extract the true echo.
Options
*
tF
True First echo
L
Largest echo
BLF
Best of Largest and First echo
Position Detect (2.8.4.2.)
Defines where on the echo the distance measurement is determined.
Options
Center
*
Hybrid (Center and CLEF)
CLEF (Constrained Leading Edge Fit)
Related parameters
CLEF Range (2.8.4.4.)
If the vessel bottom is being reported as the level instead of the actual material level (at low
level conditions), or if the dielectric constant of the liquid to be monitored is less than 3, we
recommend setting Position Detect to Hybrid and
CLEF Range (2.8.4.4.) to 0.5 m (1.64 ft).
Echo Threshold (2.8.4.3.)
Sets the minimum echo confidence that the echo must meet in order to prevent a Loss of
Echo condition and the expiration of the Fail-safe (LOE) timer. When
Confidence (2.8.6.1.)
exceeds Echo Threshold (2.8.4.3.), the echo is accepted as a valid echo and is evaluated.
Values
Range: 0 to 99
Default: 5
Related Parameters
LOE Timer (2.5.2.)
CLEF Range (2.8.4.4.)
Note
CLEF Range is referenced from Far range.
The CLEF algorithm is used mainly to allow correct level reporting for low dK materials which
may otherwise cause an incorrect reading in an empty or almost empty vessel.