Ultrasonic Sensors Series

TURCK 6/8/2018
Ultrasonic Sensors

The RU-U Ultrasonic Sensor Series from TURCK enables the user to cover large sensing ranges with fewer sensor variants. The Turck ultrasonic sensors in M18 and M30 housing styles thus effectively reduce the range of variants required for stock-keeping. This is made possible by the particularly short blind zones of the sensors, which offer large sensing ranges at the same time. In order to offer the right sensor for every application with only a few sensor variants, Turck has increased the versatility of the individual models: The simple compact version of the RU40 and RU100 modules thus enables the user to set diffuse mode and retroreflective operation as well as NC and NO switching outputs with a teach adapter. The standard  sensor variants offer several operating modes and enable the setting of switch windows or two separate  switch points, either by a teach adapter or via a teach button directly on the sensor. The High-End versions can be operated as a switch and as an analog sensor. Different operating modes, temperature compensation or the output function can also be set via IO-Link. If several sensors are installed next to each other, the customer can set the sensor parameters in synchronization or multiplex mode, in order to prevent mutual interference of the sensors.

TURCK Ultrasonic Sensors Series

Operating Principle

The operation of the sensors is based on the time of flight principle. With this a sonic pulse is emitted and the time required by the reflected signal to be received again by the same sonic transducer is measured. The distance to the object is calculated on the basis of the known speed of sound in air and output as the measured value or as a switch signal. As the speed of sound depends on the air temperature, the sensors use a separate temperature measurement to compensate the time of flight difference at different temperatures. Ultrasonic sensor technology is generally an important link in the field of industrial sensors, which is positioned  between inductive and photoelectric sensors on account of its possible object detection ranges. However, the measuring principle takes a special place as it is not based on an electromagnetic but a mechanical operating principle and therefore requires some additional knowledge for the application.


Large measuring range

TURCK Ultrasonic Sensors Series

The newly developed sonic transducers enable large measuring ranges for the entire sensor series of up to 130 cm in the M18 version and 600 cm in the M30 version. The 300 cm version in the M30 in particular operates without the need for an enlarged transducer head. This increases the options available in existing applications and enlarges the application range.

Short blind zone

TURCK Ultrasonic Sensors Series

The extremely short blind zone (e.g. only 2.5 cm in the M18 version with 40 cm range) ensures maximum downward compatibility. This enables the reliable detection of objects close to the sensor and optimum adaption of mounting depths – such as for level monitoring applications. As the blind zone has to be kept free to exclude signal errors, a short blind zone also improves the possibilities for mounting and effective object detection.

Robust mechanical design

TURCK Ultrasonic Sensors Series

The highly robust housing with a continuous threaded barrel completely made of metal is particularly short and stands out on account of the metal M12 connector, which is turned as one piece with the threaded sleeve. This eliminates any potential weak points that could cause damage in harsh environments and at low temperatures. The thread runs over the entire length of the sensor so that the mounting position can be varied as required within the mounting bracket.

Flush-front membrane

TURCK Ultrasonic Sensors Series

The smooth sonic transducer front of the M18 and M30 sensors reliably prevents contamination and the formation of particle deposits. The mechanical movement of the membrane even shakes off deposits and thus cleans itself. Particle deposits that can occur when the air humidity is high can likewise be simply wiped off completely, without any residue remaining in the transition area between the transducer layer and the transducer ring. Damage arising from sharp and pointed cleaning objects therefore becomes  a thing of the past.

Easy teach

TURCK Ultrasonic Sensors Series

In order for the user to set the sensors simply and intuitively without a PC, all M18 and M30 ultrasonic sensors are provided with a teach-in function which can be implemented via pin 5. The start of switch and measuring ranges can thus be set easily without the use of any external software.
The teach-in is carried out either via the teach adapter using the typical Turck Easy Teach function or via sensor variants with integrated pushbuttons. The pushbuttons are fitted inside the metal housing and are thus protected from accidental actuation. The setting is carried out inside a fixed time window after a preceding voltage reset. The subsequent automatic lock reliably excludes the possibility of the sensor settings from being accidentally changed.
The devices of the M18 compact design also have a teach input on pin 2, which makes this series 100% downward compatible with the previous series.

IO-Link interface

TURCK Ultrasonic Sensors Series
Besides setting via the teach-in function, the High-End variants with a switch and analog output can also be parameterized via the version 1.1 IO-Link interface. The devices can be configured in different operating modes such as in opposed mode with exclusive send and receive operation. Other features include settings for the time in which the teach button can be used after a voltage reset or also the temperature compensation setting via the internal or optional external temperature sensor. This last feature enables a more precise measuring result by including the ambient temperature in the calculation.
The user has the choice between a rising or falling characteristic for the analog output signal, and the user can set the hysteresis for the switching output. If two independent switching outputs are required instead of the switching output and analog output, these can be set to PNP or NPN switching output types with an NC or NO function.
If several devices are installed in the same environment, any mutual interference must be prevented. The sensors can therefore be synchronized or set to multiplex mode, in which the individual devices operate sequentially. The 16-bit data width of the process value can be read at a transfer rate of 38,400 baud via the supported COM2 communication type.

Benefits for the User

The features of the new RU-U ultrasonic sensor series offer clear benefits for the user:
TURCK Ultrasonic Sensors Series

System availability

Maximum process reliability is provided by the robust metal housing design in which the threaded sleeve and the connector thread are made from one piece, and also from the smooth front on which any dirt cannot accumulate. The high interference immunity also significantly contributes to the availability of this product line.


As an alternative to the flexibly configurable PNP or NPN switching outputs and the current or voltage analog outputs, IO-Link enables the sensor to be configured easily via software precisely to the requirements of the application. Besides the parameterization functions, IO-Link also enables the process value to be read out routinely at any time if the standard is used as a communication channel. This flexibility enormously increases serviceability and shortens the replacement lead time.


Turck Easy Teach simplifies the installation and commissioning of the new ultrasonic sensors. The concept enables the user, for example, to precisely define the switching or measuring range limits without the uncertainty arising from     turning a potentiometer. It is also possible to set parameters via IO-Link using the PACTware software standard popular with many suppliers. No proprietary software modules complicate the entry of the different settings and the maintenance of updates is considerably easier.

Variant reduction

With their extremely short blind zones the sensors can also detect very close objects, thus providing greater flexibility for mounting. Together with the larger measuring ranges and the possibility to teach diffuse mode, retroreflective mode as well as NC and NO operation, the user can cover a wide range of applications with fewer models of Turck's new ultrasonic sensor series.

Enhanced performance

The newly developed sonic transducers enable larger measuring ranges up to 130 cm in the M18 design and 600 cm in the M30 version. Larger transducer heads for larger ranges are no longer required. Together with the short blind zones this increases the options available in existing applications and widens the application range.

Application Examples

Conveyor belt

TURCK Ultrasonic Sensors Series

Ultrasonic sensors are ideal for measuring the profile of bulk material on a conveyor belt in harsh and dust-laden environments. The measuring is implemented above the conveyor belt. Several sensors are mounted here next to each other in order to detect the entire width of the  belt. To prevent any mutual interaction the sensor combination uses multiplex operation in which each sensor has its own address. In this mode the sensors operate cyclically in sequence. It is also possible to selectively activate each individual sensor via the controller. If the sensors are arranged further apart, the combination can also be synchronized.

Sag control

TURCK Ultrasonic Sensors Series

Foils, paper and other winding materials are often checked for sag when wound or unwound. This task is mostly carried out by ultrasonic sensors as they are not affected by surface features such as the color of the material or by dust produced from wear. Depending on the size of the sag, detection ranges of up to several meters can be measured accurately to the nearest millimeter. As a limit switch the sensor is used for starting and stopping the drive. However, it can also be used to control speed via the analog output.

Glass pane detection

TURCK Ultrasonic Sensors Series

Clear objects which are difficult to detect using photoelectric sensors are not a problem for ultrasonic sensors. From the right angle, the sensor also detects a glass pane reliably from a great distance. This makes it suitable, for example, in final assembly applications for checking the presence of clear objects, but also other mounted components such as seats, valves, seals or general interiors – as it does not depend on surface colors. The ultrasonic sensor technology also simplifies the functional testing of moving parts, such as for the end position control of seats or the open position of electrically operated car roofs.

Level monitoring

TURCK Ultrasonic Sensors Series

Liquids are a very good reflector of ultrasonic waves if they do not form any foam. Ultrasonic sensors are therefore ideal for monitoring the level of liquid containers. Spray and droplets do not affect the sensor and it even cleans itself through the through the movement of the sonic transducer. The sensor enables several switch limit values, continuous level measuring or also the direct activation of a pump. Due to its short blind zone, the sensor can be mounted where space is limited, as a minimum clearance from the surface of the liquid is no longer required.


The new RU-U ultrasonic sensor series consists of the three compact, standard and High-End series which replace the existing ultrasonic sensor portfolio.

Compact series

The compact version (RU40 and RU100) with ranges up to 40 cm and 100 cm drastically reduces the number of types since the output function can now be selected directly via a teach adapter or cable at pin 5. The compact series offers maximum ranges in the compact M18 design. The devices are available in diffuse mode and retroreflective mode.

Standard series

The standard variants can likewise be set via pin 5, or depending on the model, by means of a teach adapter or teach buttons on the device. With their double switching output, they round off the range with direct setting options for switch range limits and the output function. The sensors offer two independent switching outputs with adjustable switch points or also switch windows or analog output. It is also possible to teach the sensor for a fixed surface and thus configure a retroreflective opposed mode sensor, by which an object interrupts the signal reflection from the taught surface.


The High-End series is the switch/analog version which, besides the programming via teach buttons, can also be parameterized with different settings via IO-Link and even function as a double switch if necessary. The standard and High-End variants  in the M30 design round off the Turck ultrasonic sensor with larger ranges.

TURCK Ultrasonic Sensors Series