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 M08, M12, M18 and M30 and

40 x 40 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 retro-

reflective operation as well as NC and NO switching outputs

with a teach adapter. The standard sensor variants offer sever-

al 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.

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. Useful infor-

mation on this is available at: www.turck.en/ru

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.