Linear vs. rotary encoders

August 20, 2020



We classify encoders according to the type of motion and distinguish between two types: linear and rotary. The linear encoder is installed above the magnetic scale, and when the scale moves, the encoder reads the distance travelled. If you need to measure rotation, the rotary encoder can be installed at the end of the axis as an on-axis or off-axis variant. Both are typically used in electric motors, as they follow the position of a rotating shaft and measure the completed angle. The on-axis variant is positioned at the top of the axis and the magnet is attached to the rotating shaft. The off-axis variant is a through-hole encoder that is particularly suitable for applications where cables must be fed through the ring that is fixed around the axis and the encoder is positioned off-axis (off-axis = through-hole). The rings can be magnetised axially or radially.

Different types of movement with magnetic scale, radial and axial ring.

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