我在siemens international bbs上咨询了一下。专家回答如下：

The XML-interface in CAD programs is an option.

Normally you make your electrical drawings for example in EPLAN and then export the information to STEP7. So STEP7 is feed with the information from EPLAN, if there are made some changes then you can make the drawings AS-BUILT with the import in EPLAN of the Export from STEP7.

So it won't make drawings, it made the symbolik up-to-date in STEP7 and EPLAN for example.

The names are so in both packages the same, that's where it is fore.

[COLOR=red]看来STEP7 cax application导出的xml文件只能用于EPLAN这个专用于电气设计的工程软件，而且XML接口功能还是个选件，貌似不能用于AutoCAD...

并且这个功能在EPLAN中只是更新电气模块符号，不能生成CAD图，至于EPLAN的电气模块符号的表示方法我就不懂了，因为没用过这个软件。如果大家有用过的或者谁有兴趣就去搞个EPLAN来研究研究吧:)

我有空也来研究研究[/color]

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https://www.automation.siemens.com/ww/forum/guests/PostShow.aspx?PostID=61561#61561&language=en