Design Of Remote Monitoring System For PLC Based On Configuration Mode

Taking the sewage treatment control system composed of Modbus local area network as the research object,the features of PLC and configuration software are analyzed,and the shortcomings of the current PLC monitoring system is summarized.At the same time,the data transmission protocol and the working mode of the execution system and the PID feedback regulation principle are expounded in this paper.A design scheme of the remote monitoring system for data exchange between local area network and the Internet human-computer control interface is put forward,a new executive system controller is designed,the reliability of monitoring network operation can be improved by this remote monitoring system design in this paper.The operating features,control methods,protocol routing of the configuration software,PLC and PIC16F877 A single chip microcontroller in the system are comprehensively described in the paper.The remote monitoring and the data processing of whole system is realized with the scheme which selects the ForceControl configuration software to design the upper computer monitor configuration interface of the monitoring system.Modbus TCP/IP protocol is used between the configuration monitoring interface and the local area network control system.The configuration monitoring interface can be run on one or more PCs so as to achieve the purpose of multipoint monitoring.The Schneider Inc's Modicon M218 PLC.The data acquisition and exchange of various local area network execution system is realized with M218 which is selected as the service host of the Modbus local area network.The data routing of Modbus TCP/IP protocol and Modbus protocol are realized by using M218 as local area network router together with the network module and the remote access server.PIC16F877 A series single chip microcontroller of Microchip Technology company is used to make the controller of Modbus local area network execution system to realize the data acquisition task of the execution system and control the operation of electrical equipment.The implemention of the overall operating system reliability is ensured by closed-loop control and data redundancy processing such as PID algorithm in the implementation of system software design.The paper is organized as five chapters.The research background and the tasks of the project are introduced in the first chapter.The basic principle of PLC and the basic concept of configuration software are introduced in the second chapter.The overall design of the remote monitoring system based on configuration mode is introduced in the third chapter.The communication between the monitoring system host computer and PLC is build according to the requirements of remote monitoring in the fourth chapter.The hardware and software of the executive system controllers and establishes the communication and control between PLC and the executive system are designed in chapter five.Considering the system design scheme studied in this paper.Firstly,in the configuration mode,PLC is put forward as a part of the network server of the remote monitoring system to realize its network protocol routing function.Secondly,the current industrial local area network is connected to the internet,thus realizing the remote monitoring function of the PLC system.Finally,a new executive system controller is designed,which reduce the usage rate of PLC in industrial executive system terminals and provides the possibility to improve the performance-price ratio after the industrialization of the system.