The Application Research Of Frequency Converter And PLC In High Building Water Supply

The main content of this thesis is the water supply system designed and constructed for Ronghai Kaiyuan Building in the city of Panzhihua. The system is integrated with the living water supply and fire fighting water supply. The system is with the virtue of energy saving, smaller volume, lower investment, higher reliability and easier for maintenance and manage compared with the traditional water supply method with tower and bank.The system is based on the inner PID regulate function of frequency converter to regulate the living water stress with low constant stress, and the stress signal is sensed by the stress translator as feedback signal and the construction is sent by the computer as the given signal. The water stress is regulated to high constant stress when the fire happens. The system is also designed to supply the water by air pot with low flux at night when the demand of water decreases and pump is stopped. The design avoids the system working and pausing frequently and assures the system working with high efficiency.A distributed control system is built based on the water supplying system and the fire fighting system. Two ABB frequency converters and a Siemens programmable logic controller(PLC) are with the lower-level computer and industry computer are with the host computer. The communication between with the host computer and low-level computer not only translate the system condition, but also send the control instruction. The system condition is shown with Chinese window in the host computer, and the constant stress function is realized through the frequency converter part. The PLC controls the system logic and check the system with constant period. The fault report is also given through PLC.The system has worked since the May of 2002 and which is very reliable and very easy for control and manipulation, and energy saving is very marked. The system has passed the fire fighting inspection.