Mazda Motor Corporation

The Furukawa Electric Co., Ltd.

Furukawa Electric., Ltd.

Koji Terayama

Yoshikazu Nobutoki

Hiroaki Sakamoto

Toshiaki Kawanishi

Seiji Hirano

Hiroo Moriue

Yutaka Matsuda

Kyosuke Hashimoto

Hideki Nakazono

Osamu Michihira

Eiji Ichii

Toshifumi Ikeda

Toshitaka Hara

Toshiyuki Matsuzaki

Mitsuru Akimoto

Koji Umegaki

A multiplex data communication system including a number of communication nodes interconnected through a transmission path, each of which includes a data transmitting/receiving circuit providing a reception signal representative of normal data reception from another communication node and a transmission signal representative of normal data transmission therefrom, and a data operation circuit for controlling an electronic equipment unit associated with each communication node based on the data from the other communication node and generating the data relating to each communication node which is transmitted by the data transmitting/receiving circuit, the data operation circuit making a judgement of normality of a data communication function of each communication node based on at least one of the data reception signal and data transmission signal.

Multiplex data communication system

The object of this invention is to provide a multiplex transmission system which can effectively reduce the traffic amount associated with digital information on a communication line and can improve the efficiency of digital information transmission during a period after the beginning of activation of each of a plurality of communication nodes connected to the communication line until the communication nodes are set in a normal operation state. The multiplex transmission system includes a communication line (11) for transmitting multiplexed digital information, and a plurality of communication nodes (12A, 12B, 12C) each of which incorporates an arithmetic processing unit, and performs an information output operation for outputting digital information onto the communication line (11), and an information fetching operation for selectively fetching digital information from the communication line (11). Upon activation of the plurality of communication nodes (12A, 12B, 12C), a communication node, which is set in a normal operation state earliest, of the plurality of communication nodes (12A, 12B, 12C) outputs digital activation information, and the remaining nodes are shifted to the normal operation state in accordance with the digital activation information.

Multiplex transmission system

An object of this invention is to provide a multiplex transmission system which can temporarily use an existing data area as a destination address area and an area for designating data to be transmitted when a communication node of the multiplex transmission system is started or reset, and can prevent unnecessary data other than designated data from being transmitted even when a data sendback request is issued to another communication node to which a transmission request is to be issued. In a multiplex transmission system in which a plurality of communication nodes A to E are connected via a multiplex transmission path MB, each communication node transmits a communication frame in which event data of, e.g., switch ON states of its own lamps, motors, and the like, via the multiplex transmission path MB, and the communication frame is received by all the communication nodes when a communication state is normal, when the communication node A at the transmitting side issues a data transmission request to another communication node D, the communication node A writes data representing that a frame F is a transmission request frame in an existing data area I, and the address of the communication node D which is to receive the frame F and ID(0) to ID(3) of data to be transmitted from the communication node D in data write areas D-0 to D-3, and transmits the frame.

A plurality of gateway nodes for connecting high- and low-speed networks as multiplex transmission lines include buffers for signal transmission and reception, communication ICs, and control units. A priority order in signal processing is set for these gateway nodes. Only a gateway node which operates normally and has the highest priority executes signal transmission between the high- and low-speed networks.

Multiplex transmission apparatus for supporting prioritized

A multiplex transmission system includes a plurality of multiplex nodes interconnected by a common multiplex transmission line. Data frames are transmitted among the multiplex nodes through the multiplex transmission line. A data frame transmitted from a sending multiplex node includes a data area which is divided into subdivided areas in accordance with data transmitted therefrom and data transmitted from receiving multiplex nodes which send data in response to a send request, in accordance with the number of data pieces or the number of bits, and the receiving nodes send data to respective subdivided areas in a predetermined order, to thereby carry out a data transmission. Accordingly, the sending multiplex node can simultaneously collect data from the receiving multiplex nodes which are functionally subordinate. When any of the receiving multiplex nodes fails to return an ACK signal, the sending multiplex node retransmits the data frame.

Multiplex transmission system having plurality of nodes and common

When a message is transmitted, frame by frame, from any one (10) of a plurality of multiplex nodes to a common multiplex bus (MB) to which the multiplex nodes are connected, each of the multiplex nodes (20 and 30) determines that transmission of a frame therefrom is allowed when it detects a transmission permission signal (b, b') added to the frame after detection of and idle state of the multiplex bus, and starts transmitting a message data frame. This makes it possible to properly implement priority-based control according to the priority levels of the data frames irrespectively of variations in the reference clocks of the multiplex nodes. Further, receiving multiplex nodes perform frame synchronization at the rise of a special code (a) of a start code (SOM) of a message data frame, and then perform re-synchronization at the rise of a special bit pattern (b') which includes a passive bit and a dominant bit. This prevents synchronization from being deviated and bit errors resulting from deviated synchronization, thus leading to higher reliability of multiplex transmission.

Multiplex transmission method and a synchronizing method in multiplex

Communication nodes which respectively transmit periodic information and non-periodic information in multiplex fashion are provided separately. These communication nodes selectively transmit periodic information to a multiplex transmission line which is originally for transmitting the non-periodic information or non-periodic information to a multiplex transmission line which is originally for transmitting the periodic information in accordance with the state of transmission/reception of the periodic information and non-periodic information.

Multiplex transmission apparatus

A multiplex transmission system according to this invention includes a plurality of multiplex nodes connected to one another via a common multiplex bus, for effecting data transfer between the nodes. When reception nodes correctly receive data transmitted from one of the nodes for each frame, each of the reception nodes returns an ACK signal to the multiplex bus, registers all of the nodes connected to the multiplex bus into the ACK table in response to the ACK signal, and effects the ACK management. In this case, for example, if a door FR multiplex node causes an interruption to transmit a frame while an air-conditioning unit multiplex node is retransmitting a frame, the air-conditioning unit multiplex node effects the ACK management without regarding the ACK signal for the interruption frame as an object of the updating logic of its own ACK table.

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Hiroshima, Japan

Koji Terayama