三菱Q系列PLC串口自由通讯方法的探究

Research on Mitsubishi Q Series PLC Serial Port Free Communication Method

多种工业控制场合需要使用智能设备,并以串行通信将数据发送至上位机;三菱Q系列PLC无顺序通信方法仅支持接收“固定长度”与“变长度有固定结尾”两种数据对象,与发送“变长度无固定结尾”数据的智能设备不能妥善匹配;为此设计了一种Q系列PLC串口自由通信方法,该方法采用顺序控制程序实现了“变长度无固定结尾”数据接收、异常数据消除与通信模块故障自恢复,具有破除通信模块设定局限、可自行定义通信协议的特点;经实验其可同时支持多种智能设备,具有良好的适应性和通用性。

The intelligent device which transmits data to the upper computer by serial communication is needed in many industrial control occasions.When using the nonprocedure protocol Mitsubishi Q-series PLC which only supports receiving“fixed length”and“variable length fixed end”data objects,which can not match with the intelligent devices which send“variable length without fixed end”data properly.For this reason,a free serial communication method of Q series PLC is designed.By using sequence control program,this method realizes“variable length without fixed end”data reception,abnormal data elimination and self-recovery of communication module.Such method has the characteristics of breaking the limitation of communication module itself and making self-defining communication protocol available.Experiments show that it can support multiple intelligent devices at the same time and has good adaptability and versatility.