Analysis of a Variable Frequency Control Method for Constant Pressure Water Supply Based on Siemens S7‑1200 PLC

With the continuous expansion of urban high?rise buildings, secondary water supply systems are increasingly demanded to deliver superior pressure stability and energy?saving performance. To address the issues of response lag and high energy consumption inherent in conventional constant pressure water supply control, a variable frequency control system for constant pressure water supply is constructed based on the Siemens S7?1200 PLC. By analyzing the characteristics of water supply networks and the operational principles of parallel multi?pump configurations, a fuzzy adaptive PID pressure regulation method is proposed, which is further integrated with multi?pump loading/unloading and sleep control strategies to achieve dynamic optimal regulation of water supply pressure. Operational tests and comparative analyses are conducted using an actual engineering pump room. The results demonstrate that the proposed method effectively enhances the pressure stability and dynamic response capability of the system while reducing operational energy consumption, thereby exhibiting favorable engineering application value.