Operating Instructions

Table Of Contents
Signal Processing (2.8.)
Note
Default settings in the parameter tables are indicated with an asterisk (*) unless explicitly stated.
Near Range (2.8.1.)
The range in front of the device (measured from the sensor reference point) within which any
echoes will be ignored. This is sometimes referred to as blanking or a dead zone. The factory
setting is 50 mm (2") past the end of the antenna, and the default is dependent on the antenna
type and process connection. [See Dimension drawings (Page 175) for antenna heights.]
Values Range: 0 to 20 m (0 to 65.6 ft)
Default depends on antenna type and process connection:
Related parameters Units (2.2.1.)
Far Range (2.8.2.)
Note
Far Range can extend beyond the bottom of the vessel.
Allows the material level to drop below Low Calibration Point without generating a Loss of Echo
(LOE) state. See Sensor Mode (2.2.2.) for an illustration.
Values Range: Min. = Low Calibration Pt.
Max. = 23 m (75.45 ft)
Default: Value for Low Calibration Pt. + 1 m (3.28 ft)
Related parameters Units (2.2.1.)
Use this feature if the measured surface can drop below the Low Cal. Point in normal operation.
Propogation Factor (2.8.3.)
Note
When operating in a stillpipe, values for CLEF Range (2.8.4.4.), and for the propagation
factor, should be set according to the pipe size. See the table below.
For reliable results the antenna size must be close to the pipe size.
Compensates for the change in microwave velocity due to propagation within a metal stillpipe
instead of in free space.
Values Range 0.3 to 1.0 depending on pipe size
Default 1.0000
Nominal Pipe Size
a)
40 mm (1.5") 50 mm (2") 80 mm (3") 100 mm (4")
Parameter reference
SITRANS LR250 with mA/HART
Operating Instructions, 10/2019, A5E32220602-AG 121