An ultrasonic sensor from microsonic microsonic is not your average proximity switch or proximity switch. In many cases, an ultrasonic sensor can replace the function of a conventional proximity switch, the other way around is not always the case. Ultrasonic sensors have different types of detections and measurements that can be performed.
Ultrasonic sensors from microsonic in particular distinguish themselves from other types of sensors through the use of ultrasound and smart technologies such as an internal temperature compensation algorithm. The properties of an ultrasonic sensor and the ultrasonic sound make it possible to detect objects in different ways or measure distances with one and the same sensor.
The different types of detections and measurements with ultrasonic sensors are: diffuse proximity, reflex barrier and window operation. In addition, an ultrasonic sensor can accurately measure a distance, for this there are ultrasonic sensors with an analog output or IO-Link interface.
. Lastly, there are ultrasonic sensors with multiple outputs with which combinations of detection methods can be made. Think of an analog measurement combined with a digital full/empty detection for accurate level measurements. The two digital outputs are used to trigger an alarm when a full or empty tank is detected. In addition to this, the analog output can determine how full or how empty, for example, the tank with rising dough is.
Ultrasonic detection with window mode
The last commonly used detection method for the ultrasonic sensors is window mode. For this, optimal use is made of the foreground and background suppression. With this you can realize a window operation, also known as "window mode". The range in which the ultrasonic sensor is active can be fully defined and configured as desired. In this way, maximum freedom, but also reliability can be achieved, because the sensor is only active in a pre-specified range and everything that happens outside that set range is ignored.
This is ideal in applications where the sensor cannot be mounted directly on the application, but for example there is still a walkway in between. Or in the case of several conveyor belts along each other it can be configured that the sensor only monitors the middle conveyor belt. The microsonic pico+ series ultrasonic sensors are recommended in applications like this.
This mode is exceptionally well-suited for use in an application with multiple conveyor belts that are divided into different zones. Every sensor can be programmed to perform measurements and/or detections in a specific zone.
Reflex barrier detection
Another commonly used detection method of ultrasonic sensors is the reflective barrier, also known as "reflex barrier". This term comes from the world of photoelectric sensors, where you let the sensor "look" at a reflector and switch when the light beam is interrupted. The reflex barrier method works identically with ultrasonic sensors. The sensor is set to the present background, which you can view as a reflector, for convenience. If an object enters the sound cone of the sensor, the sensor switches. In the case of small and round objects, this method is often used to achieve reliable and consistent detection. A mic+ series ultrasonic sensor from microsonic offers a solution in these types of applications.
An example for the use of this principle is the detection of pipes that are transported on a conveyor belt. The reflector is placed behind the passing pipes; the presence of thepipe interrupts the sound wave which makes the sensor interpret the absence of an echo as the presence of a pipe.
Ultrasonic diffuse proximity detections
The “Diffuse Proximity” detection method is the most commonly used mode in ultrasonic sensors. The sensor switches to a sound reflection (echo) of an object within a user-defined range. The excellent background suppression and insensitivity to shape, color and contrast offer a very reliable measurement in most applications. The lcs+ series from microsonic includes ultrasonic sensors that are very suited for use in an application with diffuse proximity detection.
Think of detecting transparent bottles on a conveyor belt, for example. In the background there is machinery or operators working that, because of the background suppression, are ignored by the sensor.
Analog (distance) measurements with ultrasonic sensors
Most ultrasonic sensors that have an analog output are adjustable to operate voltage controlled or current controlled. The analog output "U" operates from 0-10V, the analog output "I" operates from 4-20mA. The output can also be scaled and configured (e.g. inverting, setting hysteresis, etc.). The range of the analog signal can be set as desired, usually this is based on the set measuring range. A rising (0..10V / 4..20mA) or falling (10..0V / 20..4mA) output characteristic can always be selected. For sensors that do not have a combined analog output (/ IU), you must choose one of two (/ I or / U). A good example of a sensor with a combined analog output is the mic+340/IU/TC from microsonic.
An example of an application is a tank filled with water in which the fill level needs to be monitored; so not just whether it is full or not but also how full it is.
Analog measurement with ultrasonic sensors through IO-Link interface
Ultrasonic sensors with an IO-Link interface can be integrated into an IO-Link network of equipment. This equipment communicates over the industrial IO-Link interface and consists of an IO-Link master (eg PLC) and slave devices. A sensor with IO-Link interface is always a slave device. Analog distance measurements are digitized and sent over the IO-Link interface to the IO-Link master. In addition, IO-Link offers many advantages in relation to preventive maintenance, monitoring the sensor status and the like. A suitable ultrasonic sensor for analog measurements with an IO-Link support is the pico+100/F from microsonic.
An example of an application is doing a level measurement in an oil barrel in order to signal when a refill is necessary.