Micropilot FMR66B HART
Hauser
V. 1, Rev. 2, 26-07-2022
5
Graphic conventions
• Installation, explosion and electrical connection drawings are presented in simplified format
• Devices, assemblies, components and dimensional drawings are presented in reduced-line
format
• Dimensional drawings are not to-scale representations; the dimensions indicated are
rounded off to 2 decimal places
• Unless otherwise described, flanges are presented with sealing surface form EN1091-1, B2;
ASME B16.5, RF; JIS B2220, RF
Function and system design
Measuring principle
The Micropilot is a "downward-looking" measuring system, operating based on the frequency
modulated continuous wave method (FMCW). The antenna emits an electromagnetic wave at a
continuously varying frequency. This wave is reflected by the product and received again by the
antenna.
D
R
A0032017
1
FMCW principle: transmission and reflection of the continuous wave
R
Reference point of measurement
D
Distance between reference point and product surface
The frequency of this wave is modulated in the form of a sawtooth signal between two limit
frequencies
f
1
and
f
2
:
f
t
1
2
f
2
f
1
∆t
∆f
A0023771
2
FMCW principle: result of frequency modulation
1
Transmitted signal
2
Received signal
This results in the following difference frequency at any time between the transmitted signal and the
received signal:
∆
f
=
k
∆
t
where ∆
t
is the run time and
k
is the specified increase in frequency modulation.
∆
t
is given by the distance
D
between the reference point
R
and the product surface:
