基于PLC的污水处理系统设计，PLC的程序流程梯形图，有问题请指教(Design of sewage treatment system based on PLC'PLC program flow chart of the ladder, there are problems please instruct.)

某30万吨污水处理站工艺设计图CAD2004，包含管线图，工艺图流程图，论文等。(300,000 tons of sewage treatment station process design contains a pipeline diagram, process chart flow chart papers.)