| 摘要 |
PROBLEM TO BE SOLVED: To enable easily improving response of position detection at a low cost. SOLUTION: This position detector comprises a position sensor 2 which has primary windings 22, 23 and a secondary winding 24 and generates a secondary winding voltage having phase difference corresponding to a rod position of an injection molding machine to a primary winding voltage, an analog AC voltage generating circuit 60 supplying an AC voltage to the primary windings 22, 23, a comparator 71 detecting a zerocross point of the AC voltage waveform outputted from the analog AC voltage generating circuit 60, a comparator 31 detecting a zerocross point of a secondary winding voltage waveform corresponding to a zerocross point detected with the comparator 71, a phase counter 32 outputting phase difference on the basis of detection timing of the comparator 71 and the comparator 31, and a position calculating part 43 calculating a rod position on the basis of phase difference detected with the phase counter 32.
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