Design And Implement Of Function Block Configuration Software Based On IEC61131-3

IEC61131-3 standard is the third part of IEC611131, it defines the expression and syntax of the most popular programming language in the field of industrial automation. The development of control system that consists of PLC based on IEC61131-3 is a main trend and the configuration software has an important status in the system.The function block Configuration software based on IEC61131-3 is developed in VC++6.0 platform. The configuration information of each device is managed in the form of device configuration unit. IEC61131-3 programming environment is designed based on the concept of function block configuration and modularization. The cooperation of devices and configuration software is realized using device description, XML is used to describe the configuration information of devices for data exchange in the system.The application of XML device description in IEC61131-3 configuration software is designed to resolve the problem of co-operation between devices and the configuration software. XML description criterion is defined in the aspects of I/O channels, software function units, register storage resources and basic attribute parameters of device. The method based on DOM is used for parsing XML files as the acquisition of device information. All kinds of devices are manipulated through a consistent interface from the application of XML device description. A universal design pattern for IEC61131-3 configuration software is created as the application of device description to realize device integration and co-operation in configuration platform of IEC61131-3 control system.XML language has an excellent capacity of self-explanation and can reflect the data structure of information described properly and is used for data description and storage in the middle layer between the background data of the software's user interface and the compiled instructions of special devices. Through this method, the storage of user program is separated from the programming language and the hardware platform of devices. The XML description of function block and ladder program can be transferred between different applications and devices with corresponding explanation and conversion regulation.Based on above design points, the software is used in the configuration platform of the control system to realize the function of user program editing and device integration.