Optical Encoder:

Measurement principle: Optical principle is used. Usually consists of transparent grating bars, when the light source passes through these bars, photoelectric signals are generated, and the position is measured by detecting changes in these signals.
Working mode: The light source of the grating ruler emits light, and when passing through the grating bar, the receiver detects the change of light. By analyzing the patterns of these changes, location can be determined.

Magnetic Encoder:

Measurement principle: Using magnetic materials and sensors. It usually contains magnetic strips that produce magnetic field changes as the head moves along these strips, and the position is measured by detecting these changes.
How it works: The magnetic head of the magnetic grid ruler senses changes in the magnetic field, and this change in relation to the position is converted into an electrical signal. By analyzing these signals, the location can be determined.
When choosing a grating or magnetic grating ruler, factors such as environmental conditions, accuracy requirements and cost are usually taken into account. The grating ruler is suitable for clean environments, while the magnetic grating ruler is relatively insensitive to dust and pollution. In addition, grating ruler may be more suitable for applications requiring high precision measurement.