| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide data useful for failure prediction or the like to an encoder. <P>SOLUTION: Characteristic values (amplitude, an offset value, waveform distortion of each phase and a phase difference, and so on of two-phase sinusoidal signals) of two-phase sinusoidal signals light input from the encoder are calculated at a block of "characteristic value calculation" in a control apparatus. A block of "alarm detection" checks whether the values are out of predetermined allowable ranges or not, and gives an alarm indication or the like when the values are out of the ranges. A block of "characteristic value comparison" compares the values with "past characteristic values" and analyzes the comparison results whenever "current characteristic values" are input. Maximum variations (with positive or negative signs) are obtained by calculating the differences between the current values and respective past values. A signal showing "foretaste of abnormalities" is output when the variations exceed predetermined values. Comparisons with the characteristic values calculated from encoder reference signals are also available. Besides, monitoring and comparison of characteristic values can be performed within the encoder. <P>COPYRIGHT: (C)2008,JPO&INPIT |
