Atonm Knowledge Base | Magnetic Scale vs Optical Grating Scale

Optical grating scales and magnetic scale are commonly used linear displacement sensors in stamping equipment, slides and other machinery.

What is an optical grating scale?

An optical grating scale is a high-precision linear displacement sensor that uses Moiré fringe principles and photoelectric conversion to digitally represent linear displacement. It consists of a grating and a read head. The grating is typically mounted on the moving part and the read head on the fixed part. Optical scales offer very high accuracy but require controlled environments, and are widely used in CNC machines for closed-loop servo systems requiring high repeatability.

(Grating Scale Read Head Diagram)

What is a magnetic scale?

Magnetic scale sensor is produced by non-contact magnetic field scanning. The magnetic scale consists of a uniformly magnetized tape with alternating S and N poles at uniform spacing; the read head reads magnetic field variations and the relative position between tape and head can be determined from field strength.

During installation the read head is usually mounted on the moving part and the magnetic tape on the fixed part to avoid repeated bending of the read head cable.

Magnetic scales have lower relative accuracy but superior resistance to water, oil, dust and vibration, offering better environmental adaptability and longer service life. They are advantageous in large metal-cutting machine tools, underwater measurement, wood and stone processing machines (dusty environments), and large metal rolling equipment.

(Magnetic Scale Read Head Diagram)

Grating Scale Read Head VS Magnetic Scale Read Head:

❖ Accuracy:

Optical grating scales provide higher accuracy (down to 0.1μm).

Magnetic scales offer lower accuracy (typically around 10μm).

❖ Range:

Optical grating scales are effective from 0-3m with clear accuracy advantages, but beyond 5m manufacturing becomes difficult and expensive.

Magnetic scales can reach up to 30m and offer cost advantages for ranges above 2m.

❖ Interference resistance:

Optical scales are sensitive to oil, dust and metal debris, which can severely affect accuracy and stability.

Magnetic scales excel in water, oil, dust and vibration resistance, but may be affected by nearby strong magnetic fields where optical scales could perform better.

Compared with traditional magnetic read heads, Atonm MRR series magnetic read heads have been optimized for accuracy, interference resistance, magnetic tape and installation. Key features include:

Atonm Magnetic Scale

1. High reliability: compact metal read head housing with imported flexible wear-resistant shielded cable, robust against cable wear; interference-resistant hardware and software design for stable operation;

2. High precision: selectable resolutions 1um, 5um, 10um, or customized per customer; parallel installation minimizes mechanical conversion error;

3. High environmental adaptability: resistant to oil, liquid, dust and vibration;

4. Easy installation: differential or single-ended pulse output, compact appearance for tight-space mounting.

For details on Atonm magnetic scales, click the links below:

1. Magnetic Scale Read Head MRR-H200: ###~SITEURL~###pro-detail-11.html

2. Magnetic Scale Read Head MRR-H500: ###~SITEURL~###pro-detail-12.html