| 摘要 |
PURPOSE:To extend the speed detection range by arranging plural sped sensors along a carrying path and selecting speed sensors alternatively in accordance with advance of a carrying body. CONSTITUTION:While a position sensor 102-2 detects a pallet 1, a low-level signal is supplied to the first input terminal of an AND gate 112-1 in an important position G3 by an inverter 13-2. The pulse signal of an optical switch 82-2 and that of an optical switch 82-1 are inputted to a converter 9 without superposing each other thereby even if the length between sensors 102-2 and 103-1 is shorter than the overall length of the pallet 1 because the length between important positions G2 and G3 is shrot. Thus pulse signals outputted in speed detection ranges adjacent to each other are not supplied simultaneously to the converter 9 even if these ranges overlap because the interval between important positions is short. Consequently, the speed detection range is extended to control the speed finely in wide ranges of important positions of the carrying path.
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