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Thank you for choosing a HYCONTROL instrument.
We are sure that you will be satisfied throughout its use!
1.
INTRODUCTION
Application
The VF04 2-wire level instrument uses the Time Domain Reflectometry (TDR) measuring principle and two-wire technology for level measurement.
It is designed for measuring the distance, level and volume of liquids, pastes, slurries and powder products.
The device operates in a tank, silo, rigid pipe, process vessel and side chamber.
The device is HART capable, it can be programmed using a HART® Handheld Communicator (HHC) and HyView software supplied as standard with the instrument.
Operating principle
The VF04 2-wire guided microwave level transmitter uses the TDR (Time Domain Reflectometry) principle. The instrument sends low power nanosecond wide pulses
along an electrically conductive rod, cable or coaxial probe with a known propagation speed (the speed of light). As the pulse reaches the surface of the medium or
interface of two liquids (altered dielectric constant
r
), a part of it is reflected back to the electronic module. The size of the reflected signal depends on the dielectric
constant
r
difference of the mediums or layers. (When measuring to the surface of still water through air the reflected signal's strength will be approx. 80% of the
emitted signal). The reflected pulse is detected as an electrical voltage signal and processed by the electronics. Distance is directly proportional to the flight time of the
pulse. The measured distance data is converted to a level then to a 4-20 mA current and HART signals and is displayed on the LCD display. From the level data further
derived measuring values can be calculated such as volume and mass. The TDR technology is unaffected by the other properties of the medium as well as that of the
space above it.
