Siemens SITRANS LR 300, Инструкция по эксплуатации, Страница: 70 / 140

Page 68 SITRANS LR 300 – INSTRUCTION MANUAL 7ML19985CL02
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Range Calibration Parameter (P655)
P655 Propagation Factor (F = 1)
Compensates for the change in the microwave velocity as compared with propagation in
free space, when propagation is within a stillpipe (metal).
Consult Technical Assistance at the factory for other sizes and propagation factor
numbers.
Values
Range:
0.0000 to 1.0000
Pre-set: 1
Pipe Size (I.D.) Propagation Factor
50 mm (2”) 0.827
80 mm (3”) 0.915
100 mm (4”) 0.955
150 mm (6”) 0.980
200 mm (8”) 0.990
Note:
For waveguide antennas used as stillpipes, the propagation factor value is
shown on the process device tag.
10.42 m
The propagation factor is constant for a given pipe
diameter,
or can be determined by comparing the
radar distance reading to the actual process
material distance (measured from the face of the
SITRANS LR 300 flange).
Example:
actual distance = p.f. (propagation
SITRANS LR 300 distance factor)
Using the readings shown:
10.42m = 0.827
12.6m
Enter the propagation factor : 0.827
SITRANS LR 300 distance
SITRANS LR 300.book Page 68 Monday, June 10, 2002 7:18 PM