摘要： 将PLC 梯形图逻辑表示为XML 数据，不同于采用二叉树来描述节点连接结构。根据不同的PLC 设备，配置相应的语言转换程序，可将XML 结构数据自动转换成PLC 设备的编程语言，如指令表或结构文本。若以通用单片机系统作为PLC 底层硬件，则可将XML数据转换为汇编语言或C 语言等，从而实现PLC 功能。面向新的IEC61131-3 标准，采用XML 作为与硬件无关的PLC 的编程数据具有极大的灵活性和扩展性。

关键词: 可编程控制器；梯形图；扩展标识语言；单片机系统

Abstract: The methods turning TC(trapeziform chart) logical into XML data are discussed. It differs from using bintree in describing node-link-structure. Collocating language transform program corresponding according to various equipment, it may automatic change XML structure data into the program language of PLC, for example repertoire or structural text. Transforming XML data into assembly language or C may carry out the PLC function if universal SCM(single chip micyoco) is used in PLC bottom hardware. Facing new IEC61131-3 standard, it is of huge flexibility and expansibility that the program language of PLC uses XML irrespective with hardware.

Key words: Programmable logic controller (PLC); Trapeziform chart; eXtensible markup language(XML); Single chip micyoco