Method and apparatus for the monitoring of the operation of linear and rotary encoders
OwnerStephen J. Curtisinventor
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Abstract
A system is disclosed for monitoring the operation of an encoder having a scale which is illuminated from a light source, in which light from the scale is detected by a detector, with the encoder having means coupled to the detector for detecting in-phase and quadrature signals representing scale position, means for detecting the phase difference between the in-phase and quadrature signals, and means responsive to the detected phase difference for adjusting the output of the light source to maintain its output at a predetermined level and for providing an error signal representing the amount of adjustment of the output of the light source.
Claims4
Apparatus for monitoring the operation of an encoder having a scale which is illuminated from a light source and in which light from the scale is detected by a detector, said encoder having means coupled to said detector for generating in-phase and quadrature signals representative of scale position, comprising:
- means coupled to said in-phase and quadrature signals for detecting the phase difference therebetween;
- means responsive to said detected phase difference for adjusting the output of said light source so as to maintain the output therefrom at a predetermined level and for providing an error signal representing the amount of adjustment of the output of said light source;
- and,
- means for providing an alarm indication responsive to a predetermined characteristic of said error signal.
Dependencies are inferred from the claim text.