基于ARM的PLC的CAN通信协议设计与实现

Design and Development of the CAN Communication Protocol in Programmable Controller Based ARM

在分析了PLC系统通信模块的基础上,提出了一种基于ARM实现的PLC系统的主CPU和I/O板之间进行数据采集和输出的CAN通信协议。该通信协议中,首先,主CPU向输入板请求数据。其次,输入板收到请求后向主CPU发送采集的数据。然后主CPU收到数据后对SIPROM编码进行解释执行,并通过CAN总线将输出结果发给输出板。最后,输出板对收到的数据进行处理后输出到外部设备,实现PLC控制功能。该协议通过I/O测试台的测试已成功运用于国家高档数控工程研究中心的PLC通信模块中。

Based the analysis of communication module of PLC system,this paper proposes a CAN communication protocol between main CPU and I/O board of PLC system to process data collection and output based on ARM.In this protocol,firstly,main CPU acquires data from input board.Secondly,the input board accepts the acquirement and sends colleting data to main CPU.Then after accepting data,main CPU will compile and run the SIPROM codes and output data to output board by CAN bus.Lastly,output board deals with the data form main CPU and output to the external equipment to achieve the function of PLC.This protocol has been tested by I/O testing platform and successfully applied in communication module of PLC of National Engineering Research Center.