An applied research of programmable controller remote diagnosis and maintenance system based on 3G network

This paper provided a solution on how to use latest 3G(3rd-Generation) network technology to build the remote diagnostic and maintenance system for PLC, on the basis of research and practice. With an example of Siemens S7 series PLC, the paper had a detailed discussion on the network topology, the working principle and the technical methods of the system. This solution can effectively improve remote controllability, rapid responsiveness and security of the programmable control system; and provide the new technical guarantee for the remote online diagnosis, uploading and downloading procedures and online programming. The paper also focused on how to use the IPsec protocols and VPN technology to provide security guarantees of industrial data transmission in the Internet.