| 摘要 |
PURPOSE:To correct output voltage of a thermocouple simply, by detecting a temperature of a reference point and finding electromotive force of the thermocouple concerning with its temperature and hereafter, measuring the temperature adding to the electromotive force of the thermocouple in measured temperature. CONSTITUTION:An electromotive force of a thermocouple V' is detected at a certain point of time and a difference portion of voltage DELTAVR corresponding to a temperature of a reference point at that time is held in a sample holding circuit 26 from an AD converter 20. At the same time, a voltage V'R corresponding to the temperature of the reference point at that time is outputted from a factor device 22 also and both voltage DELTAVR, V'R are added to an adder 28 and then, an output voltage VR corresponding to the output voltage of the thermocouple at the temperature of the reference point at that time is obtained. This voltage VR is added to the voltage V' by an adder 12 and an output voltage V corresponding to the electromotive force of the thermocouple at the time when the temperature of the reference point is regulated to zero degree is inputted to a subtractor 13. Next, the output of an operational amplifier 14 is inputted to an AD converter 19 through a switch 23 and also, is inputted to a factor device 17. On this occasion, the converters 19, 20 and memory devices 18, 24, are used in common. |
