Displacement encoders are used to measure a distance to an object. They consist of sensors and are based on different operating principles. There are also different types of displacement encoders.
In pneumatics, a distinction is made between linear and rotary displacement encoders. Linear displacement encoders are used to detect positions and measure distances. The measurement works either without making contact or with a contacting sensor. Rotary displacement encoders, on the other hand, are usually encoders, shaft encoders or potentiometers. A difference is made here between absolute and incremental measuring systems. With absolute measuring systems, the user can read the position value immediately after switching on the application. With incremental measuring systems, on the other hand, a homing run must first be carried out after switch-on in order to obtain the zero position. The position is then recorded by a cyclic signal.
位移编码器遵循不同的工作原理。感应系统采用完全无接触工作，最大测量范围约为 50mm。输出信号不是二进制，而是作为模拟值输出。根据磁致伸缩测量原理进行测量时，同样无需接触。此外，磁致伸缩系统工作时不产生磨损，而且是测量绝对位置。其测量范围高达 8000mm，这种产品被广泛应用于工业领域。
在接触式系统中，直线电位计是其中一种。这种设备用作具有导电电阻路径的分压器，其上有滑动器运行并记录位置。磁编码位移测量装置也是接触式系统中的一种，这种设备的最大应用范围为 50 m 左右。
除此之外，还有光电位移编码器和光学距离传感器。它们借助发光二极管或激光二极管发出的光束测量与对象之间的间距，因此也属于感应式测量设备。
Festo 提供模拟和数字位移编码器，适合测量和定位，在气动领域用途广泛。位移编码器 MME-MTS-TLF基于磁致伸缩测量原理，采取全感应式工作方式，最大特点是移动速度快。位移编码器 MLO-POT-LWG是一款推杆电位计，使用寿命长，采用绝对测量工作方式，以高分辨率见长。位移编码器 MLO-POT-TLF是一款导电塑料电位器，移动速度快，使用寿命长。