What Does Magnetic Scale Resolution Mean?

Magnetic Scale Read Head is a common precision measuring device that uses magnetoelectric effects to measure position, length, angle, and other parameters with high accuracy. Magnetic scale resolution refers to the smallest displacement the device can detect, usually expressed in length units. In this article, Atonm introduces the working principle of the magnetic scale, methods to calculate resolution, the relationship between resolution and measurement accuracy, and typical applications.

1. How a magnetic scale works

A magnetic scale is a high-precision displacement sensor consisting of a long graduated scale and a moving read head. The scale has many equally spaced magnetic stripes with alternating polarity. The sensors in the read head detect magnetic field changes of each stripe to determine the read head position and calculate displacement and length. As a non-contact measurement technology, magnetic scales provide high precision, high resolution, long life, and reliability, and are widely used in machining, precision manufacturing, optical measurement, and semiconductor production.

2. What does resolution mean?

Resolution is the minimum displacement the scale can detect, determined by the distance between adjacent magnetic stripes. It is often expressed as the smallest measurable increment. For example, a scale with 1 μm resolution can detect 1 μm displacements; actual measurement error may be smaller depending on system design.

3. How to calculate resolution

When using a magnetic scale, motion is converted to electrical signals for counting and processing. The magnetic stripe pitch is the basic measurement unit. If the adjacent stripe spacing is d and the readout has n-bit resolution, the resolution can be calculated as d/2^n. For example, with 12-bit readout (2^12 = 4096), resolution = d/4096. Higher readout resolution, better linearity, and improved temperature stability result in finer measurement increments.

4. Relationship between resolution and accuracy

Resolution and accuracy are related but not identical. Resolution is the smallest distinguishable step; accuracy is the deviation between measured and true values. Accuracy is affected by factors such as temperature, magnetic interference, and mechanical vibration. Improving accuracy requires temperature control, magnetic shielding, and mechanical stabilization.

5. Typical applications

Magnetic scales are widely used in CNC machines, machining centers, precision instruments, semiconductor manufacturing, and medical equipment for precise position and motion measurement. They will continue to be adopted in more fields, providing increasingly accurate and reliable measurements.