User's Manual

7ML19985LY01 SITRANS LR560 (FF) – INSTRUCTION MANUAL Page 139
mmmmm
D: Technical Reference
Position Detect (2.4.5.2.)
The echo position detection algorithm 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. There are four options:
• Rising
•Center
•Hybrid
• CLEF (Constrained Leading Edge Fit)
Rising
Uses rising edge of the echo.
Center
Uses center of the echo.
Hybrid
Uses combination of Center and CLEF.
CLEF (Constrained Leading Edge Fit)
• Uses the leading edge of the echo.
• Is used mainly to process the echo from materials with a low dK value.
In an almost empty flat-bottomed vessel, a low dK material may reflect an echo weaker
than the echo from the vessel bottom. The echo profile shows these echoes merging. The
device may then report a material level equal to or lower than empty
The CLEF algorithm enables the device to report the level correctly.
See
Example: CLEF off: Position set to Hybrid on page 140