Device and method for position measuring

Patent 6029118 Issued on February 22, 2000. Estimated Expiration Date:

October 2, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Error correction system for position measuring instruments
Patent #: 4490914
Issued on: 01/01/1985
Inventor: Spies

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Inventor: Schmitt

Position measuring apparatus and method having reduced memory requirements
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Issued on: 06/01/1993
Inventor: Kranitzky

Measuring device for determining an absolute position of a movable element and scale graduation element suitable for use in such a measuring device
Patent #: 5279044
Issued on: 01/18/1994
Inventor: Bremer

System for measuring lengths or angles with a high-velocity movable scanning unit
Patent #: 5294793
Issued on: 03/15/1994
Inventor: Schwaiger, et al.

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Issued on: 03/10/1998
Inventor: Thaler, et al.

Inventor

Strasser, Erich

Assignee

Dr. Johannes Heidenhain GmbH

Application

No. 942909 filed on 10/02/1997

US Classes:

702/94, Position measurement33/706, Scale reading position sensor (e.g., grid counting)33/707, Optical702/150, Orientation or position702/151Angular position

Examiners

Primary: Hoff, Marc S.
Assistant: Bui, Bryan

Attorney, Agent or Firm

Brinks Hofer Gilson & Lione

Foreign Patent References

0256 229 B1 EP. 02/25/1988

International Class

G01B 011/00

Foreign Application Priority Data

1996-10-04 DE

Abstract

An absolute position-measuring device has several graduation tracks with different graduation periods. Because of the low-pass filter behavior of the scanning elements, scanning signals with a high frequency are effected in the phase. A correction device is provided to compensate this frequency-dependent phase shift ($c;). As a function of the instantaneous frequency (f) of the scanning signal, the phase of the latter is corrected by a correction value ($c;) stored in the correction device.