| 摘要 |
PURPOSE:To detect and control accurately the temperature of a rotor by using a frequency counter which receives wirelessly the temperature information of the rotor, etc. synchronously with the number of revolutions of the rotor. CONSTITUTION:The rotors such as upper and lower surface plates 21 and 22 of a polishing machine, etc. are cooled 26 down to a proper level of temperature. This temperature is detected by a sensor 27 consisting of a sensor 27, and the oscillation frequency is radiated through an antenna 28. This frequency is received by an antenna 30 of a control part 29 containing a receiving part 31 and a microcomputer 32. Based on this received frequency, the quantity of cooling water is controlled. In this case, a light reflecting shield 50 is provided to the side surface of the plate 21. Then a pulse synchronous with revolutions of the plate 21 is made available by a light source 51 and a photodetecting element 52. This pulse is used to a gate signal of the time base to a frequency counter of the part 31. The gate is opened only when transmission/reception antennas 28 and 30 get close to each other. This prevents a count error due to deterioration of the receiving level, etc. |
