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Ultrasonic Level Sensor Features
The WL700 ultrasonic level sensors are not susceptible to error due to the
target material's color, shape or composition (e.g., transparent or opaque, liquid or solid). The ultrasonic level sensors
are particularly good for applications that must sense a non-metallic object in an environment where there is systematic, heavy
wash down, liquid, dust, heavy spray, food, ink, or other environmental hazards. Since the ultrasonic level sensor's sound
energy is used for detection, the reflecting object does not have to be metal, but can also be glass, plastic
or even paper.
Stagnant, non-agitated liquids and solids consisting of large and hard particles are good reflectors and, therefore, good
candidates for ultrasonic level sensor measurement. Fluff, foam and loose dirt are poor reflectors, and dust, mist or
humidity in the vapor space tend to the absorb ultrasonic level sensor's pulse. When these conditions are present, they are
generally not measurableby ultrasonic level sensors. As a rule of thumb, use 20% of the stated range of an ultrasonic
level sensor to see if it will overcome these conditions. Where these characteristics are present, a
WL900 radar level sensor might be appropriate.
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Architecture of Ultrasonic Level Sensors
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Operation Principle of Ultrasonic Level Sensors
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The WL700 ultrasonic level sensors are stimulated by a pulse transmitter to
generate a pressure wave that propagates to a target and then reflects back (in similar fashion to a loudspeaker) The reflected
wave is received by the ultrasonic level sensor, in receiver mode, and is converted into an electrical signal (as a microphone
would). The ultrasonic level sensor's electrical signal is amplified and processed to find the reflected echo and then calculated
to find the distance to a specific target. The distance to an object is calculated and then converted by the ultrasonic radar
level sensor to 4-20 mA signal.
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| Ultrasonic Level Sensor Still-Pipe Mounting Considerations |
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No end cut is required for pipes shorter than 6". The ID of the pipe must be greater than the OD of the transducer nozzle.
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If pipe is longer than 6", a 45° cut is required.
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