| 摘要 |
PROBLEM TO BE SOLVED: To accurately measure the location of a gap between scale pieces on an actual machine by a linear encoder with a scale constituted of a plurality of scale pieces. SOLUTION: Signals with a period corresponding to scale graduations are received by a detecting part fixed to a slider which is moved with respect to the scale. The signals are four signals with the same amplitude and 90 deg. phase shifts. Performance functions G1-G4 which do not have periodic components corresponding to the graduations and change corresponding only to the gap between the scale pieces are computed from the periodic signals. The performance function G1 is obtained as the sum of the four periodic signals, and the location of the gap between the scale pieces is computed on the basis of the location of the slider when the function reaches a specific value TH1.
|
