Toyota Jidosha Kabushiki Kaisha

Toyoda Koki Kabushiki Kaisha

Hokuyo Automatic Co., Ltd.

Daiden Co., Ltd

Toyota Jidosha Kabushiki Kiahsa

Goro Kobayashi

Hisanori Nakamura

Toshihiko Yomogida

Tsuyoshi Yamashita

Toshihiro Mori

Hideaki Tobita

Noriyuki Takao

Hidetoshi Takano

Kiyoshi Mizuno

Akira Uchida

Youichi Shibata

Susumu Koga

Shigeo Yamamoto

Preventing signals from undesirably entering and enabling interactive communication. Signals from a main line or branch line are received by receiving circuits. Signal detecting circuits detect signals, and then transmit the detected signals (detection B and detection A) to a first-arrival judging circuit. The first-arrival judging circuit determines which signal is the first arrival between the signals from the detecting circuits, and then allows one of transmitting circuits to output a signal. Accordingly, only one of the transmitting circuits generates signals, preventing signals of the other transmitting circuit from entering and enabling interactive communication.

Interactive communication circuit for selecting a transmitting circuit

An optical transmission device for interconnecting an optical full duplex transmission line and a half duplex transmission line. When a start bit of a data block of an electrical signal received from the half duplex transmission line is detected, a maintaining signal to maintain the same transmission direction is generated during which the data block can be transmitted. An optical signal is received from the optical full duplex transmission line and converted into an electrical signal. Similarly, a maintaining signal to maintain the same transmission direction is generated. In response to either one of the two maintaining signals, passage or stopping of signals by a driver for sending out an electrical signal to the half duplex transmission line and a receiver for receiving an electrical signal from the half duplex-transmission line are controlled. Possible interference of data is prevented and the transmission direction is changed over in this manner. Further, the level of an optical signal is monitored, and when the optical signal level becomes lower than a reference level, an abnormality warning data is transmitted succeeding to the data block.

Optical transmission device

A branching device to send out data received at an arbitrary one of three terminals thereof through the other two terminals. In the device, the terminals are coupled to each other by means of photo-couplers. The head of a data block received by each receiver connected with each terminal is detected, and after such detection of the head, a signal which specifies the length of the data block is generated. Thus, after communication data are received by way of an arbitrary one of the terminals, reception of communication data by way of the other two terminals is inhibited while transmission of the communication data is enabled in response to the signal specifying the data block detected. Since the transmission lines of the three directions are electrically isolated from each other by the photo-couplers, even when a failure of short-circuiting occurs at a main transmission line or a branch line or the like, communications are continued bypassing the location of the failure similarly as in the case of a failure of breaking of a wire.

Transmission line branching device

Among systems configured by connecting a plurality of sequence controllers to one communication line to intercommunicate, many systems has been disclosed which implement fault location and recovery from the faults. In one of these systems, each substation is connected to a circulating communication line via a branch line and switches are respectively disposed on the branch line and on the communication line at both sides of a connecting point of the branch line and the communication line. Further, the communication line can be formed in a loop by a spare line. In another of these systems, an integrated portion of the communication line is formed near the master station, and the communication line is connected to the master station and is configured of one continuous line which goes and backs in sequence between the integrated portion and vicinity of each substation. In that integrated portion, a switch is disposed on each one of two lines, which connect the integrated portion and each substation. Further, a switch is provided on a line which bypasses these two switches. Other systems are a composite of the above systems. Still other systems have automated portions of fault location and fault recovery.

Multiplex communication system for sequence controllers

Growing community of inventors

Okazaki, Japan

Goro Kobayashi