Endress+Hauser Micropilot FMR56 - Page 20

Installation Micropilot FMR56, FMR57 FOUNDATION Fieldbus
20 Endress+Hauser
• Metallic screens mounted at a slope
They spread the radar signals and can, therefore, reduce interference echoes.
• Variable flange seal (FMR56)
Using the variable flange seal, the device can be aligned in the direction of the product
surface. For details refer to Operating Instructions BA01048F, chapter "Accessories".
• Alignment device for FMR57
In FMR57 with alignment device, the sensor can be optimally aimed within the vessel and
thus interference echoes can be avoided. The maximum angle β is ±15°.
In particular, sensor alignment serves to:
– prevent interference reflections
– extend the maximum possible measuring range in conical outlets
6.1.6 Beam angle
a
D
W
a
D
_
=
2
2
. .
tan
W
A0016891
 4 Relationship between beam angle α, distance D and beamwidth diameter W
The beam angle is defined as the angle α where the energy density of the radar waves reaches
half the value of the maximum energy density (3-dB-width). Microwaves are also emitted
outside the signal beam and can be reflected off interfering installations.