GSD安装失败，STEP7中无法安装GSD文件的处理方法。故障信息：“An update is presently not possible. In one or more STEP 7 applications at least one GSD file or type file is being referenced.”“目前尚无法更新。在一个或多个STEP 7 应用程序中将至少有一个GSD文件或类型文 件正在被引用”