基于Modbus协议的PLC与多台电表通信研究

Communication Between PLC and Several Meters Based on Modbus Protocol

针对ABB公司的PLC在生产中应用广泛,本文基于Modbus RTU通信协议,构建了ABB PLC控制器与多台电表通信的控制系统。该系统以ABB公司的AC500-eCo PLC控制器为主站,多台B23 312-400电表为从站,通过RS485总线硬件连接。同时,利用编程软件完成硬件和网络配置,并根据Modbus RTU通信协议规格及轮询通信思想,编写PLC主站通信程序,实现PLC与多台电表之间的轮询通信控制。实验结果表明,利用编程软件在线监测,可实时显示多台电表的电压、电流和工作频率等通讯数据,并且AC500-eCo PLC与多个电表间的双向轮询通信效果良好。该研究在工业生产中具有实际应用价值。

For ABB PLC has a wide range of application in production, this paper constructs a communica- tion control system between a ABB PLC controller and several meters based on Modbus RTU protocol. The control system is composed of a AC500 - eCo ABB programmable controller which is used as a Modbus master station, and several B23 312 - 400 meters which is used as Modbus slave station. PLC connects with meters by RS485 bus. Using the programming software, we can complete the hardware equipment configuration and the network configuration. The communication program between PLC and several me- ters is designed according to the Modbus RTU communication protocol and the polling communication ide- as. The programming software can real-time display the communication parameters of voltage, current and working frequency etc, by using online monitoring. The results verify that the polling intercommunication system between AC500 - eCo PLC and meters is effective, and can be applied to the industrial engineering.