- Working Principle
1.1 Measuring Principle
Guided wave radar level meter are a kind of measuring instrument based on the time travel , radar wave are travelling as light speed , the travel time can be transformed into level signal by the electronic parts . The detector can send the HF pulse and spread along cable , when the pulse meet the level surface , it will be reflected and received by the receptor inside the instruments , then the receptor will transform the distance signal into level signal.
Input
The reflected impulse signal is transmitted along the problem to the circuit of the gauge .
The microwave processor processes this signal , and recognizes the wave echo of the microwave impulse from the material surface .
The correct wave echo signal is recognized by the intelligent software , the distance from the material surface D is proportional to the flying time of the impulse T:
D=C×T/2
C is the velocity of light .
As the distance of the empty tank E is known , so
L=E-D
Output
By inputting empty tank height E(zero point) , full tank height F(full measuring range) and some application parameter are set . With the application parameters , the transmitter will automatically adapt itself to the measuring environment, corresponding 4-20mA output .
Measuring range
H----Measuring range
L----Empty height
B----Blind area at the top
E----the minimum distance from the probe to the tank wall
The blind area at top is the minimum distance from the highest position of the material level to the measuring reference point (the thread of the flange).
The blind area at bottom is the distance around the bottom of the probe which cannot be measured exactly.
The effective distance is the distance from the top blind area and bottom blind area.
Caution: Transmitter can supply reliable level measurement only when the level is among the top
blind area and bottom blind area.
- Product Introduction
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FRL-SERIES Guided wave radar level transmitter
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Model
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FRL-701
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FRL -801
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FRL -901
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Measuring range
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30M
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6M
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6M
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Process connection
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Thread /flange
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Thread /flange
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Thread /flange
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Process Temperature
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-40-250℃
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-40-250℃
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-40-250℃
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Process Temperature
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-1.0-40bar
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-1.0-40bar
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-1.0-40bar
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Accuracy
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±1mm
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±1mm
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±1mm
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Frequency Range
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100MHZ-1.8GHZ
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100MHZ-1.8GHZ
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100MHZ-1.8GHZ
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Explosion proof/ingress protection
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EXiaIICT6/IP68
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EXiaIICT6/IP68
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EXiaIICT6/IP68
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Signal Output
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4…20mA/HART(two wires )
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4…20mA/HART(two wires )
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4…20mA/HART(two wires )
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