rotary

Incremental measuring methods are used to measure lengths and angles. They are referred to as rotary encoders, rotary pulse encoders or linear encoders. Length is determined using linear encoders, which can be incremental or digital linear encoders.

With incremental linear enc oders, the position of a moving workpiece is determined by connecting it to an evenly spaced grid. This grid can be scanned mechanically or optically. The number of detected increments is decisive for the position determination. With incremental measuring methods, the position of the workpiece relative to a reference point is determined by counting the individual measuring steps or increments.

Linear encoder, incremental (top) and digital

In addition to incremental measurement of paths and angles, in which the measured values are determined relative to the starting point, it is also possible to assign the individual measuring points to a code so that the position can be determined unambiguously, which corresponds to an absolute value measurement. For this purpose, digital linear encoders, coding rulers or coding disks are used, which are binary coded in several paths.

In the mechanical scanning of a digital linear encoder, the ruler is coded by live conductor tracks. The scanning is done with the help of sliding contacts. Similarly , optical scanning by reflected light is also possible. Scanning errors are minimized by using a one-step code (e.g. Gray code), since here only one bit is changed during a transition from one position to the next and not several.

An incremental protractor is a rotating disk divided into translucent and opaque sections. A light source and a phototransistor are used to generate rectangular pulses that are counted and then displayed. A second, offset channel on the turntable is used to distinguish between clockwise and counterclockwise rotation. The distinction is made by special evaluation electronics.