TEMPERATURE MEASURING METHOD FOR USING C-A THERMOCOUPLE IN VACUUM PROCESSOR

摘要

PURPOSE:To prevent the temperature measurement from being troubled by a voltage impressed to an object to be measured by transmitting a measuring voltage obtained by a C-A thermocouple to a photodetecting part driven by a different power source through an optical fiber. CONSTITUTION:An output of a C-A thermocoupler 1 is converted to a voltage through a correcting circuit 2 and an amplifying circuit 3. This voltage is converted to a frequency by a V/F circuit 4, and thereafter, transmitted to an optical fiber 7 through an LED driving circuit 5. In this case, an independent floating power source 6 supplies electric power to all of these circuits. This transmitted signal is returned to an electric signal by a photodetecting circuit 8, and a thereafter, converted to an electric signal again by an F/V circuit 9. In this case, electric power to the photodetecting circuit 8 and the F/V circuit 9 is supplied by a power source 10 provided separately from the power source 6. Accordingly, its temperature is measured exactly without being troubled by a voltage impressed to an object to be measured.