可以简单理解为DOP是标准发布日期，可以使用的日期。DOW是本标准强制执行的日期，上一版本标准过期的日期。

标准的几个重要日期（ DOR , DOA , DOP , DOW ）的含义：

DOR ( date of  ratification )
DOR is the date when the Technical Board confirms that the results of written vote are positive and that the EN / HD is adopted 
说明在此日期前 CENELEC 相应的技术委员会核准完成并正式推出；

DOA ( date of  announcement )
DOA is fixed by the Technical Board , normaly six moths later than dor。
Normally the annoUncement of the existence of the new CENELECEN / ENV / HD is made by each CENELEC member in the officalnational standarS jOUrnal Or in Similar publication at national level。
在此日期前 CENELEC 会员国（包括所有欧盟成员国）必须在国家层面通告上述标准已经制定完成

DOP( date of publication )
DOP is the date limit for indentical / harmonized national standards corresponding to the new EN / HD to be available。
在此旦期前 CENELEC 会员国（包括所有欧盟成员国）必须出版与其同等的国家标准（加上国家差异）或直接将其采用为国家标准；

DOW( date of withdrawel )
在此日期前旧版标准或成员国内部非调和标准停止使用，意味着所有使用就版本标准的检测证书将自动作废。
DOW is the latest date for al CENELEC members to withdraw or amend any nationa standards containing requirements conflicting with those of the new HD or EN , even if the publication of anew national standard on the basis of an HD is not intended.