Endress+Hauser Profi Bus Levelflex M FMP40 Operating Instructions Manual page 18

Mounting
18
3.4.5 Engineering hints for level measurement in bulk solids and
fluids
• Normally, rope probes should be used for bulk solids, rod probes are only suitable for short
measuring ranges up to approx. 2 m in bulk solids. This applies above all to applications in which
the probe is installed laterally at an angle and for light and pourable bulk solids.
• Normally use rod or coax probes for liquids. Rope probes are used in liquids for measuring ranges
> 4m and with restricted ceiling clearance which does not allow the installation of rigid probes.
• Coax probes are suited to liquids with viscosities of up to approx. 500 cSt.
Coax probes can measure most liquefied gases, as of dielectric constant 1.4. Moreover,
installation conditions, such as nozzles, tank internal fittings etc., have no effect on the
measurement when a coax probe is used. A coax probe offers maximum EMC safety when used
in plastic tanks.
• In the case of large silos, the lateral pressure on the rope can be so high that a rope with plastic
jacketting must be used. We recommend PA-coated ropes be used for cereal products wheat, flour
etc.
Mounting location
• Do not mount rod or rope probes in the filling
curtain (2).
• Mount rod and rope probes away from the
wall (B) at such a distance that, in the event of
build-up on the wall, there is still a minimum
distance of 100 mm between the probe and
the build-up.
• Mount rod and rope probes as far away as
possible from installed fittings. "Mapping "
must be carried out during commissioning in
the event of distances < 300 mm.
• When installing rod and rope probes in plastic
containers, the minimum distance of 300 mm
also applies to metallic parts outside the
container.
• Rod and rope probes may not, at times,
contact metallic container walls or floors.
• Minimum distance of probe end to the
container floor (C):
– Rope probe: 150 mm
– Rod probe: 50 mm
– Coax probe: 10 mm
• When installing outdoors, it is recommended
that you use a protective cover (1)
("Accessories", → ä 86").
• Avoid buckling the rope probe during
installation or operation (e.g. through product
movement against silo wall) by selecting a
suitable mounting location.
Minimum distance B of the probe to the container wall:
Wall min. distance B
Metal 100 mm for smooth walls
Plastic 100 mm, min. 300 mm to metallic components outside of the tank
Concrete 0.5 m/20", otherwise the max. possible measuring range is reduced
Distance to protruding internals min. 300 mm.
Levelflex M FMP40 PROFIBUS PA
1
B
C
Endress+Hauser
2
L00-FMP4xxxx-17-00-00-xx-003