| 摘要 |
PROBLEM TO BE SOLVED: To provide easy wiring between an external device and a signal input device. SOLUTION: A control section 20 connects the external device 2 to a current input circuit 8 by turning on respective (a)s of change-over switches 7, 18 to feed a current to an A/D converter 19. When an output value of the A/D converter 19 is within a range corresponding to a current input value, the current input is determined. When the output value of the A/D converter 19 is out of the range, a temperature measuring resistor input circuit 9 is used by turning on respective (b)s of the change-over switches 7, 18. When the output value of the A/D converter 19 is within a range corresponding to a temperature measuring resistor value, the temperature measurement resistor input is determined. When the output value of the A/D converter 19 is out of the range, a contact signal input circuit 10 is used by turning on respective (c)s of the change-over switches 7, 18. When the output value of the A/D converter 19 is a value corresponding to a contact input value, the contact input is determined, while when the output value of the A/D converter 19 is not corresponding to the contact input value, it is determined that the external device 2 is not connected. A storage section 21 stores the decision results so as to control the change-over switches 7, 18 corresponding to the stored content when a power supply is switched on. COPYRIGHT: (C)2005,JPO&NCIPI
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