Installation Instructions

Micropilot FMR20 Modbus RS485
Endress+Hauser 17
The beam angle is defined as the angle α, at which the power density of the radar waves reaches half
the value of the maximum power density (3 dB width). Microwaves are also emitted outside the
signal beam and can be reflected off interfering installations.
Beam diameter W as a function of beam angle α and distance D.
40 mm (1.5 in) antenna, α 30 °
W = D × 0.54
40 mm (1.5 in) antenna with flooding protection tube, α 12 °
W = D × 0.21
80 mm (3 in) antenna with or without flooding protection tube, α 12 °
W = D × 0.21
Measurement in plastic vessels
3
1
2
A0029540
 15 Measurement in a plastic vessel with a metallic, interfering installation outside of the vessel
1 Pipe, tubing
2 Ladder
3 Grate, railing
If the outer wall of the vessel is made of a non-conductive material (e.g. GFR), microwaves can also
be reflected by interfering installations outside of the vessel.
Please ensure there are no interfering installations made of a conductive material in the signal beam
(see the beam angle section for information on calculating the beamwidth diameter).
Please contact the manufacturer for further information.
Protective hood
For outdoor use, a protective hood is recommended.
The protective hood can be ordered as an accessory or together with the device via the product
structure "Accessory enclosed".