Micropilot M FMR250 FOUNDATION Fieldbus
Installation
Hauser
19
Measuring range
The usable measuring range depends on the size of the antenna, the reflectivity of the medium, the
mounting location and eventual interference reflections. The maximum configurable range is 70 m
(230 ft).
To achieve an optimised Signal strength it is recommended to use an antenna with as large as
possible diameter (DN200 (8") parabolic antenna, DN100 (4") horn).
Reduction of the max. possible measuring range through:
• Media with poor reflection properties (= small DC). For examples refer to table below.
• Angle of repose.
• Extremely loose surfaces of bulk solids, e.g. bulk solids with low bulk weight for pneumatic filling.
• Build-up, above all of moist products.
The following table describes the media groups and the dielectric constant
ε
r.
The respective lower group applies for very loose or loosened bulk solids.
Media group
DC (
ε
r)
Examples
Signal attenuation
A
1.6 to 1.9
– Plastic granulate
– White lime, special cement
– Sugar
19 to 16 dB
B
1.9 to 2.5
– Portland cement, plaster
16 to 13 dB
C
2.5 to 4
– Grain, seeds
– Ground stones
– Sand
13 to 10 dB
D
4 to 7
– Naturally moist (ground) stones, ores
– Salt
10 to 7 dB
E
> 7
– Metallic powder
– Carbon black
– Coal
< 7 dB
