电能质量监测系统中基于Modbus RTU的多机通信

电能质量检测与无功补偿相结合是未来发展的趋势,它的关键技术之一是数据通信。研制了一套基于数字信号处理器(DSP)的电能质量检测与无功补偿综合测控系统,该系统采用ModbusRTU(远动)报文格式,通信协议支持传统的RS-232、RS-422、RS-485及Ethernet设备,实现了以单片机为主机、DSP与PC机为从机的多机通信。主机89C 51采用中断方式进行数据发送与接收,并采用模块化的方法编程实现,DSP与PC机为从机,完成报文接收、处理、成帧及发送功能。同时依据通信规约设计了相应的通信接口,有效地解决了多机通信引起的电平冲突,实现了主机与从机的点对点通信。

Multi-computer communication based on Modbus RTU in power quality monitoring system

For the integration of power quality monitoring and reactive power compensation,one of its key techniques is data communication.A DSP(Digital Signal Processor)-based control system integrating power quality monitoring and reactive power compensation is developed.It adopts Modbus RTU(Remote Terminal Units) communication protocol,which supports RS-232,RS-422,RS-485 and Ethernet devices,to realize the multi-computer communication between MCU(Micro Controller Unit) master and DSP or PC slaves.The master,MCU 89C 51,employs interruption subroutines for transmitting and receiving messages,programmed in modularization.The slaves,PC or DSP,perform functions of message receiving,analysis,framing and response.The communication interface is designed accordingly to settle the level conflicts of multi-computer communication and realize point-to-point communication between master and slave.