Hitachi, Ltd.

Takeshi Takehara

Kotaro Shimamura

Takashi Hotta

Akira Bando

Yuichiro Morita

Shigeta Ueda

Yoshitaka Takahashi

Kazuhiro Imaie

Mitsuyasu Kido

A controller that receives an input of a status of an apparatus, executes predetermined arithmetic and logical operations, and outputs a control signal of the apparatus, and is equipped with a plurality of processors for executing the arithmetic and logical operations; a plurality of data storage elements for storing respective results of the arithmetic and logical operations of the plurality of the processors; a comparator for comparing the results of the arithmetic and logical operations of the plurality of the processors stored in the plurality of the data storage elements; and a comparison record storage element for storing a record of the comparison results of the comparator.

Fail-safe controller

In a synchronization system adopted in a synchronous-multisystem control apparatus comprising a plurality of systems operating synchronously with each other at a fixed control period, the synchronous-multisystem control apparatus can be operated in a single-system mode in the event of failures occurring simultaneously in some of the systems. The synchronous-multisystem control apparatus employs a plurality of control circuits each provided for one of the systems. Any particular one of the control circuits comprises:

Synchronization system and synchronization method of multisystem control apparatus

In a synchronization system adopted in a synchronous-multisystem control apparatus including a plurality of systems operating synchronously with each other at a fixed control period, the synchronous-multisystem control apparatus can be operated in a single-system mode in the event of failures occurring simultaneously in some of the systems. The synchronous-multisystem control apparatus employs a plurality of control circuits each provided for one of the systems. Any particular one of the control circuits includes: a period-signal generating circuit for generating a period signal indicating a start point of a control period; a synchronization-reference selecting circuit for outputting a synchronization-reference signal by referring to period signals generated by the systems; and a control-period correcting circuit for correcting a control period of the particular system by forming a judgment on a synchronization shift of the period signal generated by the particular system from the synchronization-reference signal and keeping the control period as it is in case the synchronization-reference signal is not generated.

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Hitachi, Japan

Takeshi Takehara