Research And Realization Of SoftPLC Development System Based On EP9315

In recent years, SoftPLC technology is developed rapidly because of the establishment of IEC61131-3 standard. As computer technology, communication technology and network technology develop rapidly, embedded system has been widely used in the field of the industry control. Since the embedded processor technology is becoming more maturely and has been able to meet the requirements of the industrial control, it's a trend to combine the embedded system and SoftPLC to make SoftPLC a program running in the embedded system.In this paper, several solutions of the embedded SoftPLC which exist today are analysed and an improved solution is introduced after the development status of the embedded system and SoftPLC are introduced, as well the whole design method of the development system is elaborated. By using the open source tools scratchbox and busybox, a development method based on NFS is used and a cross environment, a root file system and the runtime libraries established which are needed when embeded system is being developed and run separately. Based on the Nano-X and object-oriented C++ graphic library FLTK, the GUI of the SoftPLC system and the drawing of ladder diagram are realized, as well as the handling of the mouse and keyboard events.The major contributions of this paper are summarized as follows:1) The development architecture of the embedded SoftPLC system is proposed.By analyzing the pros and cons of the embedded SoftPLC solutions which exist today, a architecture was proposed for the embedded SoftPLC development system.2) A software and hardware platform are choosed for the embedded SoftPLC development system.The software,hardware platform and the graphic library which are needed by the development system are choosed according to the architecture proposed and the needs of the SoftPLC development system.3) The development and runtime environment are established for the development system.The paper realizes the DHCP, NFS, TFTP services setup and configuration on the host. ports ARM Linux, Microwindows and FLNX to the EP9315 platform, establishs a embedded root file system.4) Realized the embedded SoftPLC development system by using FLNXThe GUI of the system, the drawing of the ladder diagram elements and the handling of the mouse and keyboard events realized by using the open source graphical library tools FLNX, which is a Nano-X version. 5) Design of the data structures and algorithms for the development system.The pointer array data structure and the storage algorithm design for the ladder diagram and the translation algorithm for the ladder diagram to the instruction table are realized.6)The compling and running of embedded SoftPLC development system on the EP9315 platform.The organization of the development system directory and the makefile of the system are realized, and verified the correctness of the system running on the EP9315 platform.