关键机组控制系统PLC改造的探讨

Discussion on PLC Modification in Control System of Key

某聚丙烯装置循环气体压缩机组控制系统采用PLC S7-300,开工至今PLC系统故障频发,造成压缩机联锁停机,导致装置多次非计划停工,同时该系列PLC为非冗余控制系统,无SOE事件记录功能,系统时钟未同步,无法在第一时间查清楚停机原因。在2022年该装置停工检修期间,将原PLC系统改造为DCS,改造后的控制系统硬件和网络结构实现冗余配置,同时支持在线更换卡件,在线下装程序等,提高了机组控制系统可靠性、设备维护性和工艺操作性。

PLC S7-300 is adopted by the polypropylene circulating gas compressor unit as the control system.Since the start of construction,the PLC system has been failing frequently,and have led to compressor interlock shutdown,which resulted in several unplanned shutdown of the installation.At the same time,these series PLC are non-redundant control system without SOE event recording function.The system clock is not synchronized.It is impossible to find out the reason for shutdown in time.During the installation shutdown in 2022,the original PLC system was replaced with DCS.The modified control system hardware and network structure are realized with redundant configuration,while supporting online card replacement and online download procedures,etc.The reliability of unit control system,equipment maintenance and process operability are improved.