User's Manual

Appendix A: Technical reference
A.2 Echo Processing
SITRANS LR250 (HART)
220 Operating Instructions, 01/2014, A5E32220602-AB
A.2.3
CLEF Range
CLEF Range (2.8.4.4.)
is referenced from Low Calibration Point (process empty level ). When
the
Hybrid
algorithm is selected in
Position Detect (2.8.4.2.)
, the CLEF algorithm will be applied
up to the limit of CLEF Range. Above this limit the Center algorithm will be applied.
①
CLEF Range
②
(Center algorithm applied)
③
High Calibration Point (process full level)
④
Sensor reference point
⑤
Low Calibration Point (process empty level )
A.2.4
Echo Threshold
Confidence (2.8.6.1.)
describes the quality of an echo. Higher values represent higher quality.
Echo Threshold (2.8.4.3.)
defines the minimum confidence value required for an echo to be
accepted as valid and evaluated.
A.2.5
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. In radar applications, two measurement
verification options are used with
Echo Lock (2.8.5.1.)
:
Lock Off
SITRANS LR250 responds immediately to a new selected echo (within the restrictions set by the
Maximum Fill / Empty Rate), but measurement reliability is affected.
Material Agitator
A new measurement outside the Echo Lock Window must meet the sampling criteria before the
window will move to include it.
The other available options,
Maximum Verification
and
Total Lock
are not recommended for
radar.