| 摘要 |
PROBLEM TO BE SOLVED: To provide a trouble diagnosing device for an analogue signal input circuit to rapidly detect the trouble of the analogue signal input circuit. SOLUTION: Before a signal for a first analogue input port 121 is A/D- converted and read, the first analogue input port 121 is short-circuited to a GND, a resister R2 discharges the charge of a C1 during the occurrence of the trouble of an analogue signal input circuit 112. Thereafter, by A/D- converting a second analogue input port 122 connected to the GND, a charge in a sample & hold circuit 115 is discharged. A signal for the first analogue input port 121 is then A/D-converted, and when an A/D conversion value is a potential level of the GND, it is decided that an analogue input circuit is abnormal.
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