| 摘要 |
PURPOSE:To detect the abnormality of a thermocouple automatically while measuring temp. with the thermocouple by calculating the resistance value of the thermocouple at each time and detecting the abnormality of the thermocouple in accordance with a moving average value. CONSTITUTION:Signals S1, S2 for selecting selector switches (SW) 2A, 2B; 5A, 5B, a signal S3 for opening and closing SW7 and a signal S4 for turning on and off of an analog memory 4 are outputted from an arithmetic unit 11. The thermal electromotive force by by the thermocouple 1 for temp. measurement is supplied via a thermoelectric converter 3 to a temp. controller 6 and the analog memory 4 in a section I of a time chart. The electromotive force is then inputted to an amplifier 9 and is inputted via an A/D converter 10 to the arithmetic unit 11 in a section II. On the other hand, the content of the memory 4 is outputted to the controller 6. A potential difference across a reference resistor 8 is detected by the amplifier 9 and is inputted to the unit 11 in a section III. The unit 11 calculates the moving average value of the resistance values of the thermocouple 1 and detect the abnormality of the thermocouple 1.
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