| 摘要 |
PROBLEM TO BE SOLVED: To provide an electromagnetic induction type linear scale capable of determining whether or not a magnetic member deviates from its regular orbit along a detection axis beyond a tolerance level. SOLUTION: The electromagnetic induction type linear scale 1 includes a coil array 3 which consists of a prescribed number of coil elements L excited by a first AC signal, and the magnetic member 2 which is relatively displaced along its axis outside the coil array 3 and causes the amplitude of an output voltage of the coil elements L to vary in accordance with a positional relation between the coil elements L and itself, thereby measuring a relative displacement based on a phase difference between the first AC signalαand a second AC signalβobtained by composing two differential outputs of prescribed coil elements L. The electromagnetic induction type linear scale 1 further includes: a magnetic sensor 9 which is disposed along the axial direction of the coil array 3 and outputs a detection value corresponding to the positional relation between the magnetic member 2 and itself; and a determining section 10 which determines whether or not an error contained in a measurement value is within a tolerance level, based on whether or not the detection value of the magnetic sensor 9 is within a predetermined tolerance level. COPYRIGHT: (C)2009,JPO&INPIT
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