Abstract : For a long time, stepper motors have been used to control electric regulating valves to achieve automatic control of parameters such as pressure, temperature, and liquid level. This article proposes a method for controlling pressure regulating valves using frequency converters, which is simple to implement, precise in control, and inexpensive. Specifically, it utilizes RS485 communication between a PC and the frequency converter, and an application program is written to control the output frequency, phase sequence, and timing of the frequency converter, thereby controlling the opening and closing of the pressure regulating valve. A pressure sensor transmits the system pressure to the PC, forming a closed-loop control system. Keywords : Frequency converter; Automatic control; Pressure regulating valve; RS485 bus 0 Introduction The drilling pump integrated experimental equipment built in the 1980s, limited by the technology at the time, used a three-phase motor connected to the valve stem of a pressure regulating valve via a reducer to regulate the pump outlet pressure. The start, stop, and forward/reverse rotation of the three-phase motor were manually operated to open, close, and position the valve. The original control unit used old-fashioned electrical components such as manual buttons and relays, relying purely on the operator's experience. Obviously, this pressure regulation control method is difficult to operate and control precisely, posing a significant risk. Therefore, this paper proposes a method using a frequency converter to control the pressure regulating valve. The original outlet pressure regulating control unit is redesigned and modified using mature automatic control technology. To reduce investment, a method is designed that uses a frequency converter to regulate the speed, direction, and rotation time of the AC motor to control the pressure regulating valve and thus regulate the drilling pump's outlet pressure. The advantages of this method are mainly reflected in: sending control parameters to the frequency converter via a computer and setting the control parameters through a computer application program, precisely controlling the operation of the three-phase AC motor, thereby achieving the ideal effect of precisely controlling the drilling pump's outlet pressure. 1 Hardware Structure of the Pressure Regulating Unit The hardware structure of the drilling pump outlet pressure regulating unit after modification using mature automatic control technology. [b][align=center]For details, please click: Pressure Regulation Method Based on Frequency Converter Control Technology[/align][/b]