Detection based on “Ultrasonic Waves”
What is an ultrasonic / level sensor?
This section provides a detailed look at ultrasonic sensors.
DownloadOutline and detection principle
As the name indicates, ultrasonic / level sensors measure distance by using ultrasonic waves.
The sensor head emits an ultrasonic wave and receives the wave reflected back from the target. ultrasonic / level sensors measure the distance to the target by measuring the time between the emission and reception.
An optical sensor has a transmitter and receiver, whereas an ultrasonic / level sensor uses a single ultrasonic element for both emission and reception. In a reflective model ultrasonic / level sensor, a single oscillator emits and receives ultrasonic waves alternately. This enables miniaturisation of the sensor head.
Distance calculation
The distance can be calculated with the following formula:
Distance L = 1/2 × T × C
where L is the distance, T is the time between the emission and reception, and C is the sonic speed. (The value is multiplied by 1/2 because T is the time for go-and-return distance.)
Features
The following list shows typical characteristics enabled by the detection system.
[Transparent object detectable]
Since ultrasonic waves can reflect off a glass or liquid surface and return to the sensor head, even transparent targets can be detected.
[Resistant to mist and dirt]
Detection is not affected by accumulation of dust or dirt.
[Complex shaped objects detectable]
Presence detection is stable even for targets such as mesh trays or springs.
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Detection based on “Contact Measurement”
Principle and types of contact positioning sensors
Contact Positioning Sensors -
Detection based on “Ultrasonic Waves”
Comparison between ultrasonic / level sensors and optical sensors
Ultrasonic / Level Sensors
