Research And Implementation Of Embedded SoftPLC System

The origin and background of embedded SoftPLC technology are introduced firstly in this dissertation, then the key technologies of embedded SoftPLC system are discussed, lastly the design and implementation of an embedded SoftPLC system—ESPLC are explained carefully.ESPLC system consists of development system and running system (referred to as virtual machine system). The development system runs on windows platform and is used as programming environment like Tornado for application PLC program. The development system is constituted of five parts: editor, compiler, linker, debugger and communicational interface. The interface of editor is friendly, so programmer is able to do his work easily with LD, ST and FBD. The compiler and linker can compile and link source code program files into object code file that is executable to the virtual machine system. The debugger can debug program and rectify errors with the help of services provided by the virtual machine system. The communicational interface is used between the development system and the virtual machine system.The running system runs on an Arm7 platform equipped with uCLinux, it consists of running kernel module, system management module and communicational interface module. The running kernel module is used to schedule and execute application program and manage clock while the system management module to manage system states and other things. The communicational interface module is responsible for communication with the development system and I/O devices. The third chapter and the fourth chapter introduce separately the uCLinux operating system and development method ofembedded software.