The Research And Development Of Open PLC System

The traditional PLC system has some disadvantages, such as privacy technology to others, different hardware, different PLC languages in different companies. Traditional PLC system is hard to extend and update. Open PLC system aims to solve such disadvantages of traditional PLC system. Based on IEC61131-3 standards, the open PLC system is developed. The industry PC is used as hardware, and Linux+RTLinux system is used as operating system.Firstly, the whole architecture of open PLC system is build based on the research of IEC61131-3 standards. The software development is the main part in the research because the hardware adopts industry PC. The realization of the open PLC system software is introduced in details. It includes two parts: PLC executing environment and PLC editing environment. PLC executing environment is developed in Linux+RTLinux. It also includes two parts: PLC executing program and graphical user interface. The PLC executing program runs in field by the control of PLC language. PLC language is edited by user in editing environment. PLC editing environment is developed in windows with VC++. Ladder diagram and instruction list are supported in edit environment, and ladder diagram can be translated to instruction list automatic by command. Finally a specific example is given, which proves the open PLC system runs steadily, and the result is correct.