Influencing Factors on Ultrasonic Sensors
- Ultrasonic sensors detect objects, made of different materials (wood, plastic, glass, metal, …) independently from their shape (both rough and smooth surface structures), color (black, white, transparent, matt, glossy) and state (solid, liquid or powder)
- The sensing range depends on the surface properties and the angle to the object.
- Best measurement results can be achieved with objects that have smooth surfaces, positioned with an exact right angle to the sensor axis
- Very small objects or objects that partially deflects the sound will reduce the sensing range.
- Sound-absorbing materials (isolation materials, textiles, foam, cotton, …) affects a performance degradation.
Influencing factors on Ultrasonic Sensors / installation instructions
- The mounting of the ultrasonic sensor near a wall/ surface can influence the measurement
- The rougher a surface is, the bigger the distance between sensor and wall have to be selected due to undesired diffuse reflexions.
- The smoother a surface is, the smaller the distance between wall and sensor can be chosen
- In individual cases tests are necessary.
- In case of a smooth and flat surface a maximum change of angle of ca. ± 5° is possible.à sufficient reflection is available! (See Below)
- Bigger angle deviations are possible, provided that there is a rough target surface (See Below)
- The sound is diffusely reflected
- The measuring zone is reduced
In case of rough surfaces, carry out tests to identify the maximum valid angle deviation and the maximum possible measuring zone.
- If the tilt angle becomes too big, the echo is deflected completely à Signal loss (See Below)
- Level monitoring is a common application for using ultrasonic sensors
- During filling or draining, turbulence in the liquid can cause temporary moments of complete signal reflection.
Bulk Material Monitoring
- In case of measuring conical accumulations, such as with bulk material, it‘s useful to measure from the side or diagonally above to minimize signal loss from diffuse reflections.
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