Compared with the magnetic grid grating, which differs from the same point

Grating - by optical interference and diffraction theory made of sensors. When two identical grating pitch stacked together, while allowing lined constitute a slight angle, this time in the parallel light irradiation, with engraved lines vertically symmetrical able to see light and dark stripes, called moire, so moire of light diffraction and interference effects of the overall results. When moving a little grating pitch, Grate Magnets the moire fringe moves with a fringe spacing, so that we measure the width of moire lined grating width ratio measurement much easier. In addition, since each raster moire are lined by the intersection of many components, there is a lined lined when there is an error when the (unequal spacing or inclined), this error is lined and there is another raster line pattern intersection location will make a difference. However, a moire fringe is formed by a number of raster lines on the intersection, thus a change in the catch position lined, for a moire effect in terms of its very small, so that moire can play amplification and average effect.
    Magnetic scale - made use of the principle of magnetic sensors. Base feet are uniformly magnetized strip. S and N poles are arranged evenly spaced on the strip through the reading head reads S, N pole count changes.
    Grating affected by temperature, the general use of the environment at 40 degrees or less taken with disabilities. (Coordinate measuring machine are generally required in a constant temperature humidity environment transverse measurements to ensure accuracy.)
    Open magnetic scale easily affected by magnetic fields, closed magnetic scale does not have this trouble, but the cost is higher.