说明：  西门子PCS7 V7.1的高级库说明文档。做DCS系统的工控工程师必不可少的手册，中文版很难找的。在这里把我用的分享给大家。
(Advanced library description documentation for SIEMENS PCS7 V7.1. DCS system to do industrial control engineers indispensable manual, the Chinese version, it is difficult to find. Here, share what I use with you.)