Non-marking RPM measurement at smooth shafts - determining angular deviation alpha of reflector of external resonator of laser-sensor compared to vertical of optical axis

摘要

The method for measuring the alternation in the length(L) of an external resonator uses a semi-conductor laser(HL), and the parallel beam falls on a reflector(R) which can be a single mirror. The reflector(R) is adjusted, so that it stands vertical to the optical axis of the system. A photo diode(PD) measures the intensity of the light produced by the laser. Its signal is evaluated by an evaluation unit(AE). The light intensity of the laser can also be measured with a beam divider (SL) and a photo diode(PDE), with a medium having a refractive index(n) filling a chamber(N). Whereby the light intensity of the laser with monotonic alternation of the value to be measured periodically varied, and from the num-ber of periods of the variation, the light intensity of the alternation of the value to be measured is determined. The indentification of the direction of alternation of the effect to be measured, results by the evaluation of the direction dependent signal shape of the occurring periodic variat-ions of the light intensity. USE/ADVANTAGE - System for marking rpm measurement at smooth shafts. Eliminates previous disadvantages and removes restriction in its use.