Application of ultrasonic transducers in the field of industrial automation

Application of ultrasonic sensors in the field of industrial automation

Technological progress makes today's ultrasonic sensors very durable and has excellent sensing capabilities. These new technologies make ultrasonic level transducer simpler, more flexible, and more cost-effective. These newly enhanced features open up a new field of application beyond traditional ultrasonic sensor applications. Ultrasonic sensors today offer machine designers a new, creative solution found in industrial fields. A few years ago, in the field of sensor technology, ultrasonic sensors have always been the backup choice. Designers only choose ultrasonic technology when other sensing technologies fail to work. Generally, it occurs in the detection of transparent objects, long-distance sensing or local This technique is only used when the target color changes. the

The application of new technology enables today's ultrasonic sensors to withstand the test of harsh environments:

  Ultrasonic sensors with IP67 and IP69K protection levels can be used in wet environments, such as bottle washing machines.

 Built-in temperature compensation circuit, under normal or changing operating conditions, when there is an obvious temperature change, the temperature compensation circuit will be used for correction.

The surface of the Teflon model ultrasonic piezo transducer has a special coating that can be used to resist the erosion of harmful chemicals.

The advanced filter circuit can shield the ultrasonic sensor from field interference.

The new sensor sensor head has a stronger self-protection ability, can resist material damage, and adapt to a dirty environment.

Ease of use:

A notable feature of the new generation of ultrasonic sensors is the ease of use, which includes button settings, DIP switch programming and a selection of multiple programs.

The switch button is embedded in the sensor device, which makes it very easy to adjust the distance of the installed sensor. It is a very simple matter to put the target in front of the sensor and press the button. This sensor can automatically grasp the size of the window and the distance of the distance. Easy installation means that the same sensor can be used in many different applications.

The way the switches are programmed means that a simple piezoelectric ultrasonic sensor can be customized for a specific application. These personalized features include response time, output type, digital and analog options, and special settings for level/level control. 

Ultrasonic sensors generally contain multiple output types in a single sensor. Models with two switch outputs can use one sensor to sense two objects at different distances at the same time, while sensors with a switch output and an analog output at the same time It can be used for measurement and has an alarm output.

These characteristics make ultrasonic sensors more flexible and selective than other technology sensors.

  Basic Principles of Using Ultrasonic Sensors

Ultrasonic sensors moudle use the vibration of the pressure-vibrating ceramics on the head of the sensor to generate high-frequency sound waves that are inaudible to the human ear for sensing. If the sound waves hit an object, the sensor can receive the return wave. The sensor can determine the distance of the object through the wavelength of the sound wave and the time difference between the emitted sound wave and the received return sound wave. Typically, a sensor can have two settings of close distance and long distance through the setting of the button, regardless of the object In that kind of boundary, the sensor can detect. For example: an ultrasonic sensor can be installed on a pool filled with liquid, or on a box filled with small balls, and send out sound waves to the container, and determine whether the container is full, empty or is partially full.

Ultrasonic sensors also use independent transmitter and receiver models. When detecting slow-moving objects, or when fast response is required or applied in a humid environment, this kind of anti-shooting or separate ultrasonic sensor is very useful. Be applicable. Ultrasonic sensors are used when detecting transparent objects, liquids, smooth, rough and shiny, translucent material surfaces, and irregular objects. The situations where the ultrasonic sensor is not suitable are: outdoors, extremely hot environment, in a pressured container, and also cannot detect objects with foam.

Key points for ultrasonic sensor selection:

Range and size: The size of the detected object will affect the maximum effective range of the ultrasonic sensor. The sensor must detect a certain level of sound waves to be excited to output signals. A larger object can reflect most of the sound waves to the sensor, so the sensor The object can be sensed within its maximum range, and a small object can only reflect a small amount of sound waves, which obviously reduces the sensing range.

Object to be measured: The object that can be detected by the ultrasonic range sensor should be a large, flat, high-density object, placed vertically facing the sensing surface of the sensor. The most difficult to detect are those that have very small areas, or are made of sound-absorbing materials, such as foam, or have corners facing the sensor. Some objects that are difficult to be detected can be taught to the background surface of the object first, and then react to the object placed between the sensor and the background.

When used for liquid measurement, the surface of the liquid needs to face the ultrasonic sensor vertically. If the surface of the liquid is very uneven, the response time of the sensor should be adjusted longer. It will average these changes and can compare the fixed reading. Pick.

Using the ultrasonic sensor in Retrosonic mode makes it possible to detect irregular objects. In retrosonic mode, the ultrasonic sensor can first detect a flat background, such as a wall. When any object passes between the sensor and the wall, it will Blocking the sound waves, the sensor senses the interruption and recognizes the presence of an object.

Vibration: Whether it is the vibration of the sensor itself or the surrounding machinery, it will affect the accuracy of the distance measurement. At this time, some shock-absorbing measures can be considered, for example: use rubber anti-seismic equipment to make a base for the sensor, which can reduce vibration. Can eliminate or minimize vibration.

Attenuation: When the ambient temperature changes slowly, the ultrasonic sensor with temperature compensation can make adjustments, but if the temperature changes too fast, the sensor will not be able to make adjustments.

Misjudgment: Sound waves may be reflected by some nearby objects, such as guide rails or fixed fixtures. In order to ensure the reliability of detection, the influence of surrounding objects on sound wave reflection must be reduced or eliminated. In order to avoid false detection of surrounding objects, many ultrasonic sensors There is an LED indicator to guide the operator to install, to ensure that the sensor is installed correctly, reducing the risk of error.

Typical application examples of ultrasonic sensors

Ultrasonic sensors were once considered too difficult or too expensive to operate, but with the reduction in cost and ease of use, more and more mechanical designers have incorporated ultrasonic sensors into the design of machines. Industrial applications of ultrasonic sensors include detecting filling conditions, detecting reflective objects and substances, controlling the expansion of ring ropes and measuring distances. The following are a few application examples:

In the bottling workshop, inspecting the bottles

In water treatment or factory production workshop, detect liquid level and control container filling

In the liquid level control, the ultrasonic sensor integrated with the pump in and pump out function logic can control the liquid level

Detect whether the can lid is crooked or there is no lid in the packaging workshop

The industrial application of ultrasonic sensors is rapidly developing. This once very expensive and low-precision technology has become easy-to-use, high-precision and low-cost. Ultrasonic sensors have become a routine device in process control to improve product quality, to detect defective products, to confirm presence or absence and other fields. The sensor also improves productivity by reducing scrap and avoiding downtime due to damaged parts. In the future, the development of such products in this technical field will continue this trend. This is a challenge, but there has been a consensus in the industry that ultrasonic sensors are in all manufacturing areas, including quality control, process Both control and detection have great potential for development.