Rotary Encoders


Our exposed rotary encoders consist of a scanning head and a grating disk. These measuring systems are basically characterized by the following main features:

  • Non-contact optical scanning of the ratchet disk by the measuring head, thereby no mechanical retroactive effect on the shaft
  • No mechanical coupling between rotary axis and measuring system, thereby no transmission errors
  • Low space requirement
  • High resolution up to 0.135”
  • Large mounting tolerances
  • Integrated compensation of the measurement signals’ offset- and amplitude fluctuations

Optical rotary encoders are available in different sizes

Since different customers lay down different requirements in a rotary encoder, Numerik Jena provides encoders with different sizes and numbers of increments. At the same time, the rotary encoders have large mounting tolerances and reach high interpolation accuracy due to dynamic offset and amplitude correction.

Even though rotary encoders provide complex information for e.g. positioning and measuring systems, robots and rotary axes, the design is comparatively simple. A Numerik Jena rotary encoder basically consists of a scanning head and a grating disk. An optical scanning method is used in all of our incremental encoders, ensuring no contact between measuring system and rotary axis. Since this method pares down transmission errors to the minimum, Numerik Jena encoders provide the highest possible accuracy.

Differences between incremental and absolute encoders

There are two types of rotary encoders: absolute encoders and incremental encoders, each providing different advantages. Absolute encoders, also referred to as parallel absolute encoders, possess multiple code rings, ensuring a fixed relation between the physical position of the shaft and the state of the encoder. An absolute rotary encoder is used whenever it is necessary to maintain information about the position even after removing power from the system. Absolute encoders are so-called “angle transducers” because their output is an indicator for the current position of the shaft.

In contrary, the output of incremental encoders has to be processed elsewhere in order to gain further information about the motion of the shaft. This includes position, speed and distance.

Application areas of a rotary encoder

Rotary encoders are versatilely suitable for a wide range of applications. This includes pick-and-place positioning systems, robots, controlled drives, computer input devices, rotating radar platforms and other applications requiring unlimited rotation and precise position tracking. Numerik Jena furthermore provides grating disks, which are a main component for a rotary encoder.

Typical fields of application:

  • Production and inspection machines for the semiconductor industry
  • Rotary and Pivot axes
  • Pick-and-Place positioning systems
  • Controlled drives
  • Direct drives (torque motors)
  • Handling technology
  • Positioning and measuring systems for medical engineering
  • Robots