Process Control and Supervision through Internet

 In this paper the control and supervision through Internet of a process managed by PLCs (Programmable Logic Controller) is presented. The proposed software architecture allows remote users to know the sensors state and to send control signals to process actuators, by means of a graphical interface that is accessible via a web browser. Also the remote user can download control programs to PCL. It has been used the client/server architecture, where the PLC and the server PC are connected by a Visual Basic application, and the server PC and the client PC exchange data using the TCP/IP protocol. This architecture has been applied to a real system that consists in an electropneumatic manipulator. This manipulator together the PLC and the server PC form the virtual laboratory. This kind of remote control has a shiny future in the industry and the education world. From an educational view point, it allows students to verify its control algorithms in a real system from its house, analyzing the process evolution using only the web browser, without any software else. Index Terms  Programmable Logic Controller, process control, Internet, client/server model, virtual laboratory.