Siemens 7ML5431 - Page 128

Parameter reference
SITRANS LR250 with mA/HART
128 Operating Instructions, 10/2019, A5E32220602-AG
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")
Propagation Factor
0.9844
0.988
0.9935
0.9965
CLEF Range (2.8.4.4.) settings
Low calibra-
tion point -
700 mm
(2.29 ft)
b)
Low calibra-
tion point -
700 mm
(2.29 ft)
b)
Low calibration
point -1000 mm
(3.28 ft)
b)
Low calibration
point -1000 mm
(3.28 ft)
b)
a)
Since pipe dimensions may vary slightly, the propagation factor may also vary.
b)
CLEF range covers the whole measurement range except first 700 or 1000 mm from unit refer-
ence point (see A in graphic below)
①
sensor reference point
③
low calibration point
②
air gap
④
CLEF range 2.8.4.4.
A
700 or 1000 mm
Note
Flanged encapsulated antenna
For Flanged
encapsulated antenna (7ML5432) match the process connection size to the
pipe diameter whenever possible (for example, mount a DN80/3" flange on DN80/3" pipe).