Emerson Rosemount 5900C, Reference Manual

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A.1.9 Measurement principle
The FMCW-method (Frequency Modulated Continuous Wave) means that the transmitted
radar signal has a linear frequency variation around 10 GHz. The reflection from the liquid
surface has a slightly different frequency compared with the signal transmitted from the
antenna when the reflection is received. The difference in frequency is directly
proportional to the distance between the antenna and the liquid surface, and thereby also
the liquid level. This technology enables a very accurate and stable measured value.
Figure A-1: Principle of FMCW Technology
$
%
A. Frequency, f (GHz)
B. Time, t (s)
A.2 Communication / Display / Configuration
A.2.1 Output variables and units
• Level, and ullage: meter, centimeter, millimeter, feet, or inch
• Level rate: meter/second, meter/hour, feet/second, feet/hour, inch/minute
• Signal strength: mV
A.2.2 Configuration tools
Rosemount TankMaster WinSetup, Field Communicator
A.3 F
OUNDATION
™
Fieldbus characteristics
Polarity sensitive
No
Quiescent current draw
51 mA
Lift-off minimum voltage
9.0 VDC
Specifications and reference data Reference Manual
September 2019 00809-0100-5901
246 Reference Manual