Tokyo Keiki KRG-10, Руководство пользователя

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11-1
Chapter 11 Measurement principle
11.1 Measurement principle
KRG-10 takes advantage of the time-of-flight
measurement principle with microwave pulses
which have central frequency of 26GHz. Placed
on the top of tanks, KRG-10 emits microwave
pulses toward liquids or pastes in the tank.
Microwave pulses reflected from the liquid
surface are received by the antenna. The
propagation time t is converted into the distance
between the transmitter and the liquid surface.
Using t and the speed of light c, the distance D
is expressed by the following equation.
D = c × ( t / 2 ) ······ (1)
Using D and the tank height H, the level L is
expressed by the following equation.
L
＝
H
－
D ········ (2)
KRG-10 has a function to remove unwanted
echo. By using this function, the user can
prevent the erroneous recognition of the
reflected wave by unwanted echo. For more
information, please refer to
Chapter 5 LCD and
4-Keys operation and 6 Operation by
configuration software .
Fig. 11.1.1 Measurement principle
Liquid surface
D
L
H
Bottom
Antenna