In this group there are sensors for contact displacement measurement and position. The first group of linear inductive sensors is widely used in process automation, quality control of test stands, hydraulics, pneumatic cylinders and in-car engineering. The devices are characterized by high durability, reliability in harsh environments, high signal quality and good temperature stability.
The second group is analog sensors designed to measure displacement linearly in the absolute way. The most important advantages of this measurement method can be the absolute measurement method, ie when the device is switched on, the read position is an absolute position. Others include ease of signal processing and low power consumption, as well as a wide range of measuring ranges.
Optoelectronic linear encoders are used for precise measurements up to 50mm. The sensors convert the information about the change of the linear position into electrical pulses. The number of pulses corresponds to the frequency of the change of position and the frequency of pulses corresponds to the speed of motion. These devices are characterized by high resolution, precision and are suitable for a variety of measurement applications.
In the case of linear magnetic heads the measurement relies on moving the head over a special magnetic belt. The sensor converts signals into quadrature pulses in accordance with the majority of incremental encoders. The number of pulses generated by the head is proportional to the distance traveled. These devices are characterized by a high protection class and a wide temperature range as well as resistance to dirt.
Draw-wire sensors measure the linear movement of an element using a cable made of a highly elastic steel cord, which is wound on the drum using a high-vitality spring motor. The roll-up drum is axially connected with a multi-turn potentiometer, incremental or absolute encoder. Thanks to the linear measuring rule, linear motion is converted into rotary motion and then converted into resistance changes or countable pulses.
Rotary-pulse transducers with measuring wheel are designed for measuring the movement of, for example, the length of the material on the process line. When working with the meter (eg MD150), it is possible to cut the length of paper, glass, cardboard, wood, plastic and metal profiles, and measure the speed of the material and its daily wear.