Product line Sensorline

The French mathematician Pierre Vernier would definitely have been proud of our innovative interpretation and application of the principle that he introduced in 1631, although the usual German term for this measuring principle is Nonius, after the Portuguese geographer Pedro Nunes (Latin: Nonius), who, however, did not invent it.

The core feature of this innovative technique is sampling an integrated high-precision ferro-magnetic steel contour disk. The contours on this three-track code disk have dimensions of from a few 100 µm to 2 mm; the disk is manufactured using light exposure and etching processes, just like an optical code disk.

The surface contours are sampled using giant magneto-resistive sensors (GMR). The GMR effect was discovered in 1987 and is based on the surface layer effects of multiple layer magnetic systems. GMR-based read and write heads soon revolutionized the development of computer hard disks and have since been installed in their millions.

These magneto-resistive sensors return a sinusoidal signal for each track. The contours on the surface of the code disk impart a phase offset to the returned signals, and a highly integrated circuit then performs a vernier analysis on the result. This phase offset is unique within one complete revolution, and thus permits absolute determination of the position.

This innovative technology enables our magnetic absolute rotary encoders to offer unrivalled singleturn 16-bit resolution and a precision of 0.1°.

  back