| 摘要 |
PROBLEM TO BE SOLVED: To simplify the circuitry while reducing cost and current consumption by providing means (e.g. a switching circuit) for controlling current supply to a sensor depending on the type of sensor thereby limiting a measuring current generating part to one circuit. SOLUTION: When a sensor is a thermocouple 2, a CPU 8 delivers a switching control signal for connecting a measuring current generating part 31 with a cold contact compensation circuit 12 to a switching circuit 32. The switching circuit 32 controls switching of an internal switch circuit to connecting the measuring current generating part 31 with the reference contact temperature compensation resistor 3 of the cold contact compensation circuit 12. Furthermore, the CPU 8 controls switching of a multiplexer 1 to fetch a sensor output from the thermocouple 2. When the sensor is a temperature measuring resistor, the CPU 8 delivers a switching control signal for connecting a measuring current generating part 31 with the temperature measuring resistor to a switching circuit 32. The switching circuit 32 controls switching of the internal switch circuit to connect the measuring current generating part 31 with a connection terminal P1 to the temperature measuring resistor. The CPU 8 fetches a sensor output from the temperature measuring resistor.
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