说明：  该双恒压供水控制系统是以PLC控制为核心，变频调速技术为基础，并结合压力传感器、变频器、水泵、继电器、接触器等组成。在此系统中，PLC将压力设定值与测量值的偏差经PID运算后得到的控制量作用到变频器，从而通过变频器控制水泵的转速调节管网的压力，实现恒压供水的目的
(constant pressure of the water-control system based on PLC control at the core, VVVF technology as the foundation, and the combination of pressure sensors, inverter, pumps, relays, contactors and other components. In this system, PLC will set value and pressure measurement errors by the PID analyzing the role of the volume control inverter thereby inverter control pump speed control network pressure, constant pressure to achieve the purpose of water supply)