The Development System Of Embedded Soft PLC Design

Traditional PLC has played a huge role in the field of automation controlling. Butrecently with the rapid development of computer technology and the formulation ofIEC61131-3 standard, Soft PLC is getting a rapid development. Meanwhile, along with theembedded system widely used in industrial controlling, the combination of embedded systemand Soft PLC is an inevitable trend in the field of industrial controlling. Soft PLC can be usedas an embedded application running in an embedded system. Embedded Soft PLC can notonly realize functions of Soft PLC which is based on PC platforms, but also has highflexibility in aspects of real-time performance, resource allocation, system tailoring and costcontrolling.Embedded Soft PLC system can be divided into two parts, development system andoperation system. Development system is run on PC platform, while operation system is runon embedded platform. And Development system is the foundation of Soft PLC system. Thispaper is based on embedded software development system of PLC for the main researchcontents, which is to provide a friendly user interface and good PLC programmingenvironment, Furthermore can be compiled and simulated PLC program. This topic is usedby C++ language which is object oriented, with Windows operating system and Visual C++development environment, to realize the soft PLC system function of development system.Through analyzing the structure and principle of soft PLC, this paper determined thenecessary functions of Soft PLC development system, which can specific for editing module,compile module and simulation module. Through the analysis of IEC1131-3 internationalstandards for PLC programming language and according to the provisions of the respectivefeatures, this paper choose ladder diagram (LD) as this development of PLC systemprogramming language.Firstly develop editing module, including data structure of ladder diagram, and functionsof generation, display and modification. Next develop compile module, and design ladderdiagram information format which operation system can identify, and according to the formatto realize compiler function. Then develop simulation module, via analyzing the runningprocess of PLC, design the simulation process and realize its logic control function.Finally this paper simply introduced PLC operation system, and experimental test, theresults show that the development system design is reasonable and correct, and fully meetsthe design requirements.