Method for evaluating measurement signals which are obtained by scanning an incremental scale by means of a scanning unit, and measuring device for carrying out this method

摘要

In a method for evaluating measurement signals which are obtained by scanning an incremental scale (1) by means of a scanning unit (2), at least two analog signals (sin a, cos a), whose basic form is sinusoidal and which are mutually phase-shifted, being generated and evaluated by a computer (5), the direction of movement of the scanning unit with respect to the scale is determined and signals which specify this direction of movement are applied to the computer (5). The measurement signals (sin a, cos a) are digitised in an analog-to-digital converter (8) and fed to the computer. Correction values for standardising the signals (sin a, cos a) with respect to amplitude, dc component and phase angle are determined from the scanning of at least one complete signal train, and the computer (5) is calibrated with the aid of these correction values, so that it uses a corrected signal variation as a basis for the interpolation calculation of signals corresponding to incremental fractions of the graduation. The number of the complete graduation increments of the scale that are obtained in the measurement section is also acquired in the computer and linked with the result of the interpolation calculation to form the displayed value. IMAGE