| 摘要 |
PROBLEM TO BE SOLVED: To provide an absolute encoder, which can accurately detect erroneous reading in a code pattern with a simple structure even though a conventional absolute encoder had such a problem as complicating the circuit and processing for detecting the erroneous reading. SOLUTION: In the absolute encoder, a pattern detection part 21 reads out a part containing a redundancy pattern of k bits from a code pattern of a code plate 1, on which the code pattern is presented with a pattern of n bits corresponding to an absolute position data, a data conversion part 23 computes the absolute position data, by extracting n bits out of n+k bits while sequentially shifting and an error detection part 22 to perform detection to determine whether erroneous reading occurs, depending on whether each absolute position data computed shifting is continuous.
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