基于PLC的电厂化学水处理程控系统设计.doc

摘要 I 基于 PLC 的电厂化学水处理程控系统设计摘要化学水处理控制系统是电厂中非常重要的一部分,自然水中含有大量对电厂设备有腐蚀性的成分,直接使用会对设备造成极大的破坏,因此必须经过严格的处理才能使用。本课题先分析了传统控制方式和现代控制方式的优缺点,然后分析自然水的成分及其对化学水处理的影响,再分析选择化学水处理工艺,并完成此次设计的系统硬件配置和软件设计。根据分析, 本次设计选择的工艺为反渗透(RO)—混床工艺流程,选择双滤料过滤器、反渗透装置以及混床等为主体装置, 进行了 PLC 输入/输出分配、外部接线图的设计及控制系统的流程图的设计,并用 STEP7 编译软件编制了控制系统的梯形图并转换为指令语句。该系统经过模拟调试,可有效实现过滤器的运行与反洗,反渗透的运行和混床的运行、反洗和再生功能。关键词工艺, PLC ,梯形图,模拟调试攀枝花学院本科毕业设计(论文) ABSTRACT II A BSTRACT The system of chemical water treatment is an important auxiliary system of power plant , natural water contains corrosive ingredients ina large number of power plant it directly can cause a great damage to the equipment,so it must tobe treated before using it. First , the project analyses the quality of natural water and the influence of impurity on chemical water treatment, and then chooses the chemical water treatment technics of power plant. On the basis, pletes hardware configuration and software design of chemical water treatment control system. According to the analysis , the project chooses the craft of reverse osmosis (RO)-mixed bed, using dual-media filters, reverse osmosis devices and mixed beds and soon. After the design of PLC I/O assignment and the exterior diagrams and the flow charts of the control system, pilers Ladder Diagram of control system with STEP7 and transforms it into directive statements. Through simulative debugging, This system can efficiently realize the operation and backwashing of filters, the running of reverse osmosis and the operation, backwashing and regeneration of mixed beds. Key word s C raft,PLC,Ladder diagram,Simulation debugging 攀枝花学院本科毕业设计(论文) 目录目录摘要................................................................................................................................. I ABSTRACT ......................................................................................................................... II 1绪论..........................................................................................