What Is A Grating Ruler And How Does It Work

What Is A Grating Ruler And How Does It Work

The optical scale is also called grating scale position sensor, which is divided into closed grating, absolute open grating and incremental open grating

Grating ruler is a length displacement detection element, commonly understood as a ruler, such as vernier calipers used in life, tape measure used by decoration masters, etc., are based on the scale of the ruler, the length of the object can be known by comparing the measured object with the scale. The scale on the grating is the scale produced by photoengraving.

Grating is on the fiberglass tape scale, the photolithography stripes and gaps, between the two is called the gate distance (generally 40 or 20μm, but also 2μm). The reading head scans a grating distance and transmits a signal. The principle of reading is similar to that of an optical encoder. The grating movement is also read by the LED light source and the corresponding signal is obtained.
The grating ruler determines the minimum scale (grid distance) and the reading head determines the minimum resolution. The accuracy is completed by the ruler and the reading head together. The accuracy is the error that may occur at every 1m. The general accuracy of the grating ruler is ±15μm/m, ±5μm/m, and smaller. Of course, the accuracy is also linked to other factors, the rise and fall of the temperature, will make the grating scale thermal expansion and cold contraction, resulting in small changes in the scale.

How to choose the raster scale

1, precision,
2. Type of received signal (ABZ, digital quantity)
3. Installation space
4. Maximum speed