Operating Instructions

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.
It is used from Low Calibration Point (process empty level ) up to the level defined by CLEF
Range (see illustration below). Above that point the Center algorithm is used. For more detail
see CLEF Range (Page 227).
Values Range: 0 to 20 m (0 to 65.6 ft)
Default: 0.0 m
Related parameters Position Detect (2.8.4.2.)
Parameter reference
SITRANS LR250 with mA/HART
Operating Instructions, 10/2019, A5E32220602-AG 123