Siemens Sitrans LR250, Руководство по эксплуатации, Страница: 124 / 306

Parameter reference
SITRANS LR250 (PROFIBUS PA)
122
Operating Instructions, 08/2014, A5E32221386-AC
Echo Threshold (2.5.7.3.)
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 (2.5.9.1.) exceeds
Echo Threshold (2.5.7.3.), the echo is accepted as a valid echo and is evaluated.
Values Range: 0 to 99
Default: 5
Related Parameters Timer (2.3.6.)
Use this feature when an incorrect material level is reported.
CLEF Range (2.5.7.4.)
Note
CLEF Range is referenced from Low Calibration Point (process empty level).
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 235).
Values Range: 0 to 20 m (0 to 65.6 ft)
Default: 0.0 m
Related parameters Position Detect (2.5.7.2.)
①
CLEF Range
②
Sensor reference point
③
Low calibration point (process empty level)
In applications with low dK materials we recommend setting CLEF Range to 0.5 m (1.64 ft) and
Position Detect (2.5.7.2.) to Hybrid.