| 摘要 |
PROBLEM TO BE SOLVED: To provide a deterioration determination device capable of detecting the change of a value from a fraction to several times the resistance held by a thermocouple, and determining existence of a comparatively small deterioration generated in the thermocouple. SOLUTION: Each one end of compensating lead wires 11, 11 comprising a copper-constantan wire is connected respectively to terminals n1, n2 on the output side of a K thermocouple 10, and a voltage measuring device 12 is connected to the other terminals n3, n4 of the compensating lead wires 11, 11, and the output from the voltage measuring device 12 is inputted into an operation device 13. A current source 17 is connected to the terminals n3, n4 through a control device 16 for controlling make and break of lead wires 15, 15, and the operation device 13 is equipped with a threshold reference table 13a for comparing with a potential difference generated in the K thermocouple when a current is provided to the K thermocouple from the current source 17.
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