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传统PLC常采用CAN总线作为其扩展总线,CAN总线的通信速率往往难以满足工业现场大型应用场合的需求,为提高其通信速率,本文提出了一种利用工业实时以太网技术作为PLC扩展总线的方案,该方案使用FPGA来实现工业实时以太网。本文介绍了基于FPGA的以太网实现方法,在标准以太网的基础上,利用定时器实现PLC主从站间通信的周期性,同时对以太网数据的发送和接收程序进行了系统的描述。测试表明,该方案可以有效地提高PLC的通讯速率。
Traditional PLC often adopts CAN bus as its expansion bus. The communication speed of CAN bus is often difficult to meet the needs of large-scale industrial site applications. In order to improve the communication speed, this paper presents a solution using industrial real-time Ethernet as a PLC expansion bus , The program uses FPGA to achieve industrial real-time Ethernet. In this paper, FPGA-based Ethernet implementation method is introduced. On the basis of standard Ethernet, the timer is used to realize the periodicity of PLC master-slave communication. At the same time, the sending and receiving procedures of Ethernet data are systematically described. Test shows that the program can effectively improve the PLC’s communication rate.