Hitachi, Ltd.

Nissan Motor Company Limited

Seiichiro Ogawa

Ikuro Masuda

Takeo Yuminaka

Shigeo Shiono

Hisayoshi Shiraishi

Jinichi Sakurai

Takasi Abe

Toichi Kudo

An arithmetic logic unit for a stored program sequence controller stores a program equivalent to a relay sequence in a program memory and executes sequence control in accordance with the stored program. A first push-down storage register for sequentially storing logical operation results at branch start points of the relay sequence and a second push-down storage register for sequentially storing logical operation results for branches connected to the branch points based on the logical operation results stored in the first push-down storage register are provided. The arithmetic logic unit carries out the operations based on the logical operation results stored in the first and second push-down storage registers.

Arithmetic logic unit of a sequence controller

Disclosed is a signal transmitting and receiving apparatus for transmitting and receiving parallel-by-word data signals, converting the parallel-by-word data signal to serial-by-word data signal, and transmitting the serial-by-word data signal to control units connected in a multi-drop connection configuration or receiving the signals transmitted from the control units. An external control mode and an internal control mode in receiving the parallel-by-word data signal, a simulation mode, and the prevention of competing status between a write timing of the parallel-by-word data to a buffer memory and a read timing of the data for converting it to serial-by-word data are described.

Signal transmitting and receiving apparatus

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Ichikawa, Japan

Seiichiro Ogawa