| 摘要 |
A radar level detector for detecting that a surface of a product in a tank has entered a predefined distance range in an upper half of said tank, said level detector comprising a transmitter for transmitting an electromagnetic transmission signal into the tank, a propagation device for allowing said transmission signal to propagate towards said surface and for returning a reflection of said transmission signal from said surface, a selector for selecting a portion of said reflection, said portion defining said predefined distance range, a detector for setting a discrete signal to an active level if said portion includes information indicating a surface reflection, and an interface for communicating said discrete signal externally of said level detector. As it is not necessary to determine the filling level at every point in time, the signal processing of the detector according to the present invention can be significantly simplified, leading to a more cost efficient product and less power consumption.
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