Temperature input unit, temperature measuring device, and recording medium

A temperature measuring device to measure a temperature of a measurement target with at least one of a thermocouple or a temperature measurement resistor, the temperature measuring device comprising:

• a disconnection detector to feed a disconnection detection current for disconnection detection to the thermocouple and a compensating wire connected to the thermocouple in a case of measurement of the temperature with the thermocouple;
• a thermocouple detection circuit to detect a thermoelectromotive force of the compensating wire and the thermocouple both connected to the temperature measuring device in the case of measurement of the temperature with the thermocouple;
• a temperature measurement resistor detection circuit to feed a constant current to the temperature measurement resistor, which is connected to the temperature measuring device, and to detect a resistance of the temperature measurement resistor in a case of measurement of the temperature with the temperature measurement resistor;
• a connection switch to connect the compensating wire to the thermocouple detection circuit or the temperature measurement resistor detection circuit;
• and
• a measurer to calculate the temperature of the measurement target based on the thermoelectromotive force detected by the thermocouple detection circuit in the case of measurement of the temperature with the thermocouple, and to calculate the temperature of the measurement target based on the resistance of the temperature measurement resistor detected by the temperature measurement resistor detection circuit in the case of measurement of the temperature with the temperature measurement resistor,
• wherein the measurer
• controls, before measuring the temperature of the measurement target with the thermocouple, the connection switch to connect the compensating wire to the temperature measurement resistor detection circuit, and calculates a predicted value of a voltage drop resulting from a resistance of the compensating wire occurring in response to the disconnection detection current, and
• controls the connection switch to connect the compensating wire to the thermocouple detection circuit, and subtracts the predicted value from a measured value of the thermoelectromotive force detected by the thermocouple detection circuit to calculate a corrected measured value of the thermoelectromotive force detected by the thermocouple detection circuit and based on which the measurer calculates the temperature of the measurement target.

A non-transitory computer readable recording medium storing a program executable by a temperature measuring device that measures a temperature of a measurement target with at least one of a thermocouple or a temperature measurement resistor, the temperature measuring device including:

• a disconnection detector to feed a disconnection detection current for disconnection detection to the thermocouple and a compensating wire connected to the thermocouple in a case of measurement of the temperature with the thermocouple,
• a thermocouple detection circuit to detect a thermoelectromotive force of the compensating wire and the thermocouple both connected to the temperature measuring device in the case of measurement of the temperature with the thermocouple,
• a temperature measurement resistor detection circuit to feed a constant current to the temperature measurement resistor, which is connected to the temperature measuring device, and to detect a resistance of the temperature measurement resistor in a case of measurement of the temperature with the temperature measurement resistor,
• a connection switch to connect the compensating wire to the thermocouple detection circuit or the temperature measurement resistor detection circuit, and
• a measurer to calculate the temperature of the measurement target based on the thermoelectromotive force detected by the thermocouple detection circuit in the case of measurement of the temperature with the thermocouple, and to calculate the temperature of the measurement target based on the resistance of the temperature measurement resistor detected by the temperature measurement resistor detection circuit in the case of measurement of the temperature with the temperature measurement resistor,
• the program causing the temperature measuring device to perform operations comprising:
• controlling, before measuring the temperature of the measurement target with the thermocouple, the connection switch to connect the compensating wire to the temperature measurement resistor detection circuit;
• calculating a predicted value of a voltage drop resulting from a resistance of the compensating wire occurring in response to the disconnection detection current;
• controlling the connection switch to connect the compensating wire to the thermocouple detection circuit;
• and
• subtracting the predicted value from a measured value of the thermoelectromotive force detected by the thermocouple detection circuit to calculate a corrected measured value of the thermoelectromotive force detected by the thermocouple detection circuit and based on which the measurer calculates the temperature of the measurement target.