| 摘要 |
PROBLEM TO BE SOLVED: To provide an analog signal reading system which uses a photocoupler 3a to attain insulation between an input and an output and automatically calibrates the influence of change with lapse of time. SOLUTION: This analog signal reading system uses an analog switch 2 for switching an input signal current 1 and a reference current 7, the first photocoupler 3a, a second photocoupler 3b and a CPU 4. The CPU 4 stores an output characteristic of the first photocoupler 3a in advance. The input signal current 1 and the reference current 7 are inputted to the CPU 4 through the analog switch 2 and the first photocoupler 3a to be subjected to comparison/operation. In addition, the analog switch 2 is switched by the CPU 4 through the second photocoupler 3b. COPYRIGHT: (C)2004,JPO&NCIPI
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