Denso Corporation

Jiro Sato

Tomohisa Kishigami

Hajime Kikkawa

Shinichi Senoo

Tatuya Katoh

A secondary device receives an instruction message accompanied by a counted value and compares the received counted value with a counted value stored in an internal memory. Thus, it is determined whether the currently received instruction message is the same as a previously received instruction message and an execution of a process based on the previous instruction message was completed. When the received instruction message is not the same, the secondary device transmits a response message after executing a process according to the received instruction message. In contrast, when the instruction message is the same, the secondary device transmits a response message based on a process history in the internal memory without executing the process according to the received instruction message.

Network system, network device, and program product

A multiplex communication system includes a plurality of networks and a data relay unit. Each node included in each network resets a relay flag which is a predetermined bit of a data frame, when it sends the data frame to another node. If the data frame requires to be relayed, the data relay unit receives and relays the data frame. The data relay unit includes a relay flag check (RFC) section and a relay flag setting (RFS) section. The RFC section checks whether the relay flag of the data frame is set. If relay flag is set, the RFC section inhibits the data frame from being relayed. If the relay flag is not set, the RFC section allows the data frame to be relayed. The RFS section sets the relay flag of the data frame when the data frame is relayed.

Data relay unit and multiplex communication system capable of inhibiting data relay in response to failure

A multiplex communication system includes a plurality of networks and a data relay unit. When an event occurs in a node belonging to one of the networks, the node (sender node) sends a wake-up frame before it sends an event frame. In response to the wake-up frame, the nodes belonging to the same network which includes the sender node are activated and the data relay unit sends a wake-up frame to the respective networks for activating the networks. When it is determined that each of the networks is activated, the data relay unit sends a network activation notifying (NAN) frame regarding the network to all the networks. The NAN frame regarding the network represents that the network is activated. The sender node sends the event frame in response to the NAN frame regarding the destination network of the event frame.

Multiplex communication system capable of activating destination network beforehand

A plurality of electronic control units is continuously supplied with electric power to be capable of communication one another even when respective controlled devices are in inoperative condition. Each ECU transmits a sleep NG information along with its device ID when it not allowed to remain in the sleep mode. An abnormality detection unit connected to the ECUs through communication lines monitors the sleep NG information of each ECU to detect the ECU remaining activated for more than a wait period which is required for the ECU to shift to the sleep mode. The device ID of the ECU which is detected as remaining activated is stored in a memory so that any abnormal location may be specified by the stored device ID.

Growing community of inventors

Kariya, Japan

Jiro Sato