Abstract: A control apparatus performs transmission and reception of data among a plurality of units mounted on a backplane. The control apparatus includes a communication unit that is mounted on the backplane and connected to the units via one-to-one communication lines and relays data among the units by using the communication lines.

Abstract: A controller controls a time stamp providing unit to provide a periodic transfer packet with a time stamp showing the synchronous timing of periodic control designated by the control period timer using the global time indicated by a global timer. Devices are corrected to synchronize operation period timers with the periodic control, by using the time difference between the synchronous timing time of periodic control indicated by the time stamp of the transmitted periodic transfer packet and the global time indicated by global timers, at periodic operation timing of the operation period timers.

Abstract: Transmission delay in a serial bus connected network is determined by transmitting a Ping packet which is replied to in a physical layer of the bus from a request node to a response node, and measuring the time required from transmission of Ping packet by the request node until a Self—ID packet corresponding to the Ping packet is returned to the request node. The delay deviation between cycle timers of the request node and the response node is compensated by this transmission delay. The delay deviation may be also compensated using a time stamp.

Abstract: There is provided a serial transmitting section for serially transmitting a command frame 100 which is sent from a host controller 1 to a positioning type servo amplifier 30 and a command follow-up type servo amplifier 50. In the command frame 100, an information section, into which information to be transmitted is inputted, has discrimination data for showing a selection between the positioning type servo amplifier 30 and the command follow-up type servo amplifier 50. In the positioning type servo amplifier 30 and the command follow-up type servo amplifier 50, there is provided information reading section for reading the content of an information section after the discrimination data of the command frame 100 by the discrimination data of the command frame 100.

Abstract: Transmission delay is determined by transmitting a Ping packet which can be replied in the physical layer from a request node to a response node, and measuring the time required from transmission of Ping packet by the request node until Self_ID packet corresponding to the Ping packet is returned to the request node. The delay deviation amount between the cycle timers of the request node and response node is compensated by this transmission delay. The delay deviation amount may be also compensated by using the time stamp.

Abstract: A controller controls a time stamp providing unit to provide a periodic transfer packet with a time stamp showing the synchronous timing of periodic control designated by said control period timer using the global time indicated by a global timer. Devices correct to synchronize operation period timers with the periodic control, by using the time difference between the synchronous timing time of periodic control indicated by the time stamp of the transmitted periodic transfer packet and the global time indicated by global timers, at the periodic operation timing of said operation period timers.