1. Working pressure control accuracy control circuit is the main transformer control circuit. The regulating working pressure of the speed regulating valve shall exceed the maximum pressure of the hydraulic system, including all kinds of working pressure damage on the hydraulic oil pipe road.

2. Connect the remote control pressure reducing valve 2 to the remote control port of the main speed regulating valve 1 and adjust the valve 2 to adjust the system software pressure. The main speed regulating valve is used to control the safety protection working pressure value of the precision system software.

3. According to the adjustment toughness of the hydraulic proportional speed regulating valve of the frame hydraulic press, which is proportional to the input current, the goal of stepless adjustment of the working pressure of the system software can be completed by continuously changing the incoming power flow of the proportional speed regulating valve.

4. According to the proportion between the adjustment toughness of the hydraulic proportional speed regulating valve of the frame hydraulic press and the input current, continuously changing the input flow of the proportional speed regulating valve can complete the target multi-level voltage transformation control circuit for stepless adjustment of the working pressure of the system software. This circuit can be used when the hydraulic transmission system must be operated by multi-level working pressure. The remote control port of the main speed regulating valve 1 in the figure is respectively connected with the remote control pressure reducing valves 2 and 3 according to the three position four plug-in valve 4. When in the hydraulic directional valve, the working pressure of the system software is controlled by the speed regulating valve 1. When the hydraulic directional valve is in the left position, the working pressure of the system software is controlled by valve 2, and when the right position is powered on, it is determined by the valve. Therefore, the system software can set three working pressure values. Note that the control accuracy working pressure of remote control pressure valves 2 and 3 must be less than the constant working pressure of main speed regulating valve 1.