Micropilot S FMR533 4 to 20 mA HART Mounting
Endress+Hauser 13
Measuring conditions
• The measuring range begins where the beam hits the tank bottom. Particularly with dish bottoms
or conical outlets the level cannot be detected below this point.
•For overspill protection, it is possible to define a safety distance (SD) additionally to the
blocking distance (BD).
• Depending on its consistence, foam can either absorb microwaves or reflect them off the foam
surface. Measurement is possible under certain conditions.
• The smallest possible measuring range B depends on the antenna version (see Fig.).
• Tank diameter and height should be at least dimensioned such that a reflection of the radar signal
on both sides of the tank can be ruled out ("Beam angle", → ä 12).
• In case of media with a low dielectric constant (groups A and B), the tank bottom can be visible
through the medium at low levels (low height C). Reduced accuracy has to be expected in this
range. If this is not acceptable, we recommend positioning the zero point at a distance C (see Fig.)
above the tank bottom in these applications.
• In applications with parabolic antenna, especially for media with low dielectric constants
(media group A and B, → ä 14) , the end of the measuring range should not be closer than
1 m (40") to the flange (cf. BD in Fig.).
• The safety distance (SD) is set to 0.5 m (20") by default, generating an alarm in case the product
level rises inside the safety distance.
L00-FMR533xx-17-00-00-en-011
Behaviour if measuring range is exceeded
The behaviour in case of the measuring range being exceeded can be freely set:
The default setting is a current of 22 mA and the generation of a digital warning (E681).
reference: flange / BD (cf. picture) reference: antenna tip (cf. picture)
Blocking distance Safety distance recommended additional settings
BD [m (ft)] SD [m (ft)] A [mm (in)] B [m (ft)] C [mm (in)]
FMR533 1 (3.28) 0.5 (1.6) 1000 (40) 0.5 (1.64) 150 to 300 (6 to 12)
BD
SD
A
B
C
100%
0%
max. level
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