Do Magnetic Grating Sensors Belong to Linear Encoders or Rotary Encoders?

Magnetic grating sensors can belong to either linear encoders or rotary encoders.

1. Linear Encoders

Principle and structural characteristics

Magnetic linear encoders mainly consist of a magnetic scale and a read head. The magnetic scale is produced by depositing a uniform magnetic film on a non-magnetic substrate (such as glass or stainless steel), then recording equally spaced magnetic signals (usually sine or square waves) with a recording head. The read head senses the magnetic signals. When the head moves linearly relative to the scale, it induces an electrical signal corresponding to displacement.

For example, in CNC machines the magnetic scale is mounted alongside the machine bed and the read head on the moving table. As the table moves, the head reads the magnetic signal changes to precisely measure displacement.

Applications

Magnetic linear encoders are widely used in precision machine tools and automation lines for linear displacement measurement. In PCB drilling machines, for example, they provide precise X/Y positioning with accuracy often reaching ±0.01mm or better.

2. Rotary Encoders

Principle and structural characteristics

Magnetic rotary encoders have the magnetic grating applied to the circumference of a rotating part (such as a shaft) with the read head fixed nearby. As the part rotates, the head reads changes corresponding to angular position or speed. The concentric grating accuracy directly affects measurement precision.

For example, in industrial robot joints, the magnetic rotary encoder mounted on the motor shaft measures joint angle to enable precise motion control.

Applications

Magnetic rotary encoders are commonly used in motor speed control and robot joint angle measurement. In automated storage stackers, they help precisely control platform movement and fork actions.

Looking ahead, advances in magnetic materials and signal processing algorithms will further improve magnetic grating sensor stability and accuracy, reduce external interference, and expand applications in both linear and rotary measurement fields, supporting higher levels of industrial automation.