基于MODBUS通讯协议的层绕机控制系统

基于MODBUS协议的层绕机控制系统主要由人机界面、PLC和变频器组成,采用RS485串行总线网络实时控制焊丝层绕机的工作,较好地解决了焊丝恒张力层绕和主动放线的技术难题。说明系统控制过程、各控制部分的功能、通讯程序编制、通讯时的变频器参数设置,详述西门子S7-200PLC与深圳汇川MD320T变频器采用MODBUS协议实现通讯的方法,给出通讯程序涉及的协议格式、数据传输形式、自由通讯端口编程所用到的发送指令和接收指令,以及通讯初始化程序和CRC校验程序。

Layer winder control system based on MODBUS communication protocol

The layer winder control system based on MODBUS protocol is main made up of interface, PLC and frequency converters. Adopting RS485 universal serial bus network to control welding wire layer winder work in real time, the technical problems of welding wire layer winding in constant tension and active payoff are resolved better. System control course, functions of control sections, programming communication, frequency converters parameters setting as communication are explained. The method to realize the communication of SIEMENS S7 - 200PLC with Shenzhun Huichuan MD320T frequency converters by MODBUS protocol is expounded, the communication program referring to protocol form, data transmission mode, the sending instruction and receiving instruction used for free communication port programming, and the communication initialization program and CRC checking routine are given.