Hitachi, Ltd.

Hidechiyo Tanaka

Manabu Kubota

Yasuhiro Kiyofuji

Masakazu Ishikawa

Katsumi Yoshida

Tatsuyuki Ootani

Yasuyuki Furuta

Takenori Kasahara

Atsushi Nishioka

Hisashi Terae

Syuichi Nagayama

Fujiya Kawawa

A fault diagnosis apparatus and method capable of simultaneously detecting the fault of a multiplexer and the fault of an A/D converter and isolating and identifying causes of these faults, the multiplexer and the A/D converter being used in a multi-channel analog input/output circuit. Test-voltage values are inputted from a diagnosis-voltage input unit into the multiplexer and the A/D converter constituting an analog-signal conversion unit, the multiplexer having plural channels, the A/D converter converting outputs from the multiplexer into digital signals, the test-voltage values being different from each other for each channel of the multiplexer. Comparisons are made between the digital voltage values and the test-voltage values inputted, the digital voltage values being outputted for each channel of the multiplexer. From this comparison result, it is judged whether the multiplexer is at fault or the A/D converter is at fault.

Fault diagnosis apparatus and fault diagnosis method of multi-channel analog input/output circuit

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Hitachiota, Japan

Hidechiyo Tanaka