Abstract : This paper introduces the design principle and control process of variable frequency technology in industrial automated water supply systems, as well as the practical effects achieved by this technology. Keywords : PID control; frequency converter; PLC 0 Introduction In traditional water supply system design, the most unfavorable situation of the pipeline network (where the flow rate is the largest and the required head is also the highest) is generally used as the main basis for selecting the pump unit design. However, when the pipeline flow rate decreases, overpressure in the pipeline will occur at low flow rates, and energy waste is inevitable. Since variable frequency speed control water supply systems do not require the construction of elevated water tanks and water towers as in traditional water supply systems, they avoid secondary pollution and reduce civil engineering investment. Moreover, they can adjust the pump speed in real time according to the system flow requirements, achieving stepless speed regulation. This is very suitable for the transformation of ordinary water supply systems, and is a technical transformation project that is convenient to transform, requires little investment, has quick results, and is highly practical. 1 Design Principle Pump speed regulation can be achieved through many means, among which variable frequency speed regulation is currently the most ideal. Variable frequency speed control (VFD) works by sampling the water pressure in the water supply system's pipeline using pressure sensors. The pressure signal is converted into an electrical signal and sent to a regulator for comparison and calculation with the user-set pressure value. The result is then converted into a frequency adjustment signal and sent to the VFD. The VFD adjusts the power frequency of the water pump motor according to the received frequency adjustment signal, thereby regulating the pump's speed. [b][align=center]For more details, please click: Application of Variable Frequency Technology in Water Supply Systems[/align][/b]