| 摘要 |
PURPOSE:To attain packet re-transmission without increasing a load of a communication node in a control system network provided with a token confirmation means to each communication node. CONSTITUTION:An auxiliary node (a) and an auxiliary network 2 are provided and when a communication node of a network 1 for usual communication cannot receive transmission acknowledge data ACK corresponding to transmission data Tx and a transmission fault is caused, the auxiliary node (a) stores the transmission data Tx whose transmission is failed in the internal reception buffer and an auxiliary network 2 is used till the transmission acknowledge data ACK having the same identification data as the transmission data Tx are obtained to send the transmission data Tx again whose transmission is failed. Thus, a transmission fail rate is reduced and the reliability of the network is enhanced and the load of the communication node for usual communication is not increased.
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