Patent ID: 8725827
Filing Date: 2014-05-13
Classification: H04L

Abstract:
1. A data communication system that performs data communication between a master station and a plurality of slave stations in a token passing system employing an Ethernet, wherein the master station includes: a communication processing unit that performs, as first data transmission and reception processing, data transmission and reception between the master station and the slave stations performed by circulating a token frame between the master station and the slave stations; and a data transmission and reception processing unit that is connected to an arithmetic processing device and performs, as second data transmission and reception processing, data transmission and reception performed between the arithmetic processing device and the communication processing unit, the arithmetic processing device subjecting data transmitted from the slave station to arithmetic processing and generating data transmitted to the slave station, wherein the communication processing unit performs, as a third data transmission and reception processing, data transmission and reception performed between the communication processing unit and the data transmission and reception processing unit, and wherein, when data reception processing for circulating the token frame between the master station and the stave stations and receiving the data from the slave stations in the first data transmission and reception processing is subjected to a retry processing, in the retry processing, the communication processing unit circulates the token frame between the master station and the slave stations and receives the data from the slave stations without performing the third data transmission and reception processing, and performs the third data transmission and reception processing after the retry processing.