Installation
Micropilot S FMR540 4 to 20 mA HART
14
Hauser
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.
• 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 avoided.
• In case of media with a low dielectric constant (media 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 principle it is possible to measure up to the tip of the antenna with FMR540. However, due to
considerations regarding corrosion and build-up, the end of the measuring range should not be
chosen any closer than
A
(see Fig.).
L00-FMR54xxx-17-00-00-yy-009
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 (E651).
1)
1)
All values are based on reference conditions.
A [m (in)]
B [m (in)]
C [mm (in)]
FMR540 (without extension)
2)
2)
The length of a sensor extension shall be added to "A" when selecting the extension option.
0.6 (23.6)
> 0.5 (> 20)
> 300 (> 12)
100%
0%
B
A
C
