The measurement of angular displacement is very important in modern industry. Especially in machine tool industry, the rotation angle of mechanical parts was often highly demand. This needs to accurately measure and control the angular displacement.

The Austria AMOSIN steel grade measurement system including three parts:steel grade feet, reading-head and electronic assessment. The steel grade feet was installed on the inner ring of the bearing（figure 2), it is a steel ring with grids uniform distribution on. The reading-head was installed on the outer ring of the bearing (figure 1), it is near the steel grade feet, but not touch; there is a 0.1--0.2mm clearance between them.

When Working, the bearing rotary, the steel grade feet and the reading- head (figure 3) do non-contact relative motion, then turn the data which was collected by induction to the electronic evaluation  (figure 6) through the cable (figure 5). The electronic evaluation then transfers the information to square wave or Positive harmonic signal. These signals were put into the numerical control system In the machine tools, to realize the measuring and control to the angular displacement.

Advantage of the steel measuring system:

A. No- contact inductive encoder, no wearing.

B. The precision can compare to the optical encoder, high precision < 2 arc-second

C. Double reading-head measuring system can correct the deviation on  bearing radial in real time.

D. High speed, high dynamic resolution, high dynamic performance.

E. No magnetic components, no hysteresis reaction, no demagnetization dangerous

F. Strong anti-jamming to solid grain, oil etc. Protection grade IP67, resistance to water pressure and dense dust, not sensitive to any type of dirt and pollutants.

G. Compact design, no matter for narrow installation space.

H. Easy for installation, high speed for adjustment, high resistance to impact and vibration, good stability, high reliability

I. Can output sine wave (1VPP) and square wave signal (TTL), compatible with Siemens and Fanuc numerical control system, etc