[China Glass Network] Presence detection is one of the more common applications of sensors. Generally, proximity sensors are often used to accomplish this purpose. But when it comes to special measurement objects, this method is usually very difficult. For example, glass. Due to its special physical properties, its presence detection has always been a problem. However, in some practical applications, the presence detection of glass is indispensable. Among them, the detection of the sunroof in the automobile manufacturing process is one, and in this case, the ultrasonic sensor can be used for measurement.
An ultrasonic sensor is a sensor that performs distance and position sensing measurements in the form of transmitting and receiving ultrasonic waves. Since the sunroof of the car is mostly transparent, the various sensors of the optical principle cannot measure. The ultrasonic sensor is capable of emitting ultrasonic waves outward and receiving echoes from the glass surface. The distance of the object is estimated by combining the time of receiving the echo and the wave velocity. When the time constant measured by the sensor is within the preset range, it indicates that there is glass present at the sunroof of the detected vehicle; conversely, when the sensor does not receive the echo, it indicates that the presence of the glass is not detected.
Honeywell's 900 Series ultrasonic sensors are available in a wide range of sub-series models to solve some of the most difficult problems. When using this sensor, the object to be detected can be any material and is independent of color. It can detect transparent, shiny, and dark, opaque objects. Non-contact inspection is possible from transparent glass bottles to black rubber tires. And the 900 Series can also be used in dusty harsh environments without compromising accuracy and repeatability, which many other sensors can't. The 900 series can also perform background suppression, that is, it can detect only the target within the set distance and is not sensitive to the background material after the object is detected. The 900 Series uses a high frequency carrier with an operating frequency of 130 to 300 kHz, which is much higher than the noise frequency in a typical industrial environment.