Research Of PLC Simulation Platform

Because of the limitations of objective condition such as place, equipment and funds, it is hard to fix real control objection in the laboratory for PLC experiment, leading the experimental results not intuitive enough. For that matter, this paper designed a virtual simulation PLC Experiment System, which is suit for teach, easy to be operated on and with high-level simulation degree. Students could do many PLC experiments on the system, and could develop various simulating PLC experiments as they like, and the running situation would be displayed dynamically on the HMI, through which the students could give the rein to their imagination and creativity, improved the teaching effect on PLC experiment evidently.Based on the analysis of the requirement of the basic function of the system, the overall framework of the system is built as follows: the simulation object library part is used to store simulation components of the components of a virtual reality subjects; the data communication part uses OPC technology to achieve the data transmission between simulation software and PLC; the experimental operation part provides an experimental platform for the students to do the simulation experiments, on which the students can carry out typical experiments or develop more new operations. So the whole system could be divided into three major parts: the simulation object library part, the data communicated by OPC technology part, and the experimental operation part.The architecture design of simulation object library module is based on SQL Server 2005 database platform. SQL Server 2005 database is easy to use and has good stability, which has a good compatibility with Visual C# developing software. Meanwhile, it provides a guarantee for stable operation of experimental software. The simulation object library can be used to store the simulation object components database of simulation object components needed by experiments and realize the preservation function database of preserving students' experimental design functions. And the system uses Flash technology which has good animation production capacity to make a variety of simulation experiment components, which could be chosen and called to build various forms of PLC simulation experiments.The data communication module realizes data interactive function between simulation software and PLC, using the middleware technology advantage of OPC, it realizes efficiency and real-time between software and PLC. Also it is very good to connect the OPC application under the COM platform and .NET platform, using OPC specification under the .NET environment realizes the data transmission between simulation software and PLC. In addition, using OPC technology to make the simulation experimental software can be connected to communicate various types of PLC, instead of developing a communication module for each PLC, which can meet the teaching needs of a variety of PLC.The experimental operation module provides students with two experimental modules for framework experiments and optional self-test experiments. The experimental framework modules provide a component library to facilitate students to choose the components and a perfect experimental auxiliary function, which helps students do convenient design simulation experiment. Optional self-test experiments provide students with some typical PLC experiments, finally take three typical PLC simulations for example to introduce the use of simulation platform, and thus verify the function of simulation platform expressing in the experimental teaching role. The PLC virtual simulation experimental platform can cultivate the students of automation and related major to get close to the actual control system's engineering training, which has a strong practical significance.