| 摘要 |
PROBLEM TO BE SOLVED: To detect abnormality with high precision without increasing a space or cost even if applied to a line driver type encoder. SOLUTION: An abnormality monitor detects abnormality by inputting output signals of the encoder 12, which are a plurality of signals having different phases, as a pair of differential signals to a control device 350 via a wiring system including a power source line and a signal line, and by processing the differential signals, wherein the control device 350 includes: a first abnormality detection means composed of line receivers 351A, 351B and counters 335A, 335B for converting the plurality of differential signal groups to each of the digital signals, a pulse number comparison abnormality detection unit 336, and the like; a second abnormality detection means composed of timers 338A, 338B, a pulse width comparison abnormality detection unit 340, and the like; and a third abnormality detection means composed of level measuring means 341A, 341B, AD conversion units 332A, 332B, level abnormality detection units 333A, 333B, and the like. COPYRIGHT: (C)2011,JPO&INPIT
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