Title:
通信装置、同期通信システムおよび同期通信方法
Document Type and Number:
Japanese Patent JP4760978
Kind Code:
B2
Abstract:
A communication device and method are provided in which even when communication devices are connected in series to a transmission path, devices connected to the individual communication devices are synchronized so that a communication cycle can be reduced. A second communication device (2) includes a relay path (260) and a return path (261) which do not pass through a storage device, and a path selection switch (250) therefor. A first communication device (1) instructs switching of the return path (261) from a transmission path (5), measures a transmission path delay time, notifies the second communication device (2) of it, and sends a reference time of the first communication device for each communication cycle. The second communication device corrects its reference time using the transmission path delay time and the reference time. Also when a new second communication device (2) is found during synchronized communication, the first communication device (1) performs transmission path delay measurement using the remaining time in the communication cycle. Furthermore, the first communication device and the second communication device include means for detecting a frame start signal and reducing transfer delay.
Inventors:
Hidetsugu Koga
Fukuda Mamoru
Tatsuhiko Sato
Fukuda Mamoru
Tatsuhiko Sato
Application Number:
JP2009509123A
Publication Date:
August 31, 2011
Filing Date:
March 26, 2008
Export Citation:
Assignee:
Yaskawa Electric Co., Ltd.
International Classes:
H04L7/00; H04L45/121
Domestic Patent References:
| JPH10142361A | 1998-05-29 | |||
| JPH11305812A | 1999-11-05 | |||
| JPH1091222A | 1998-04-10 | |||
| JP2007189457A | 2007-07-26 |
Attorney, Agent or Firm:
Shohei Oguri
Hironori Honda
Toshimitsu Ichikawa
Hironori Honda
Toshimitsu Ichikawa