Method of electronically correcting position errors in an incremental measuring system and measuring system for carrying out the method

摘要

In the operation of an incremental measuring system, a measuring scale is scanned for generating periodic sinusoidal, analog measured-value signals. Digital countable signals are derived from the measured-value signals in conjunction with an electronic subdivision of the scale and are delivered to an electronic evaluating unit. Each countable signal is associated with a certain phase angle of the measured- value signals. For an electronic correction of position errors, predetermined signal levels are detected at a series of first points, which have an electrical spacing corresponding to a sub-incremental step constituting a fractional part of a scale increment, and these signal levels are alternatively detected at a series of second points, which have the same electrical spacing as the first points and are offset by a fractional part of this spacing, and in accordance with a correction program the measurement is selectively evaluated in response to the signal levels at these points so that corrections can be effected in steps corresponding to only a fractional part of such sub-incremental step.