For example, I press a workpiece with a hydraulic press, and the pressure gauge shows 0.3MPa. Then I change the cylinder pressure. When I type, I choose the 0.3MPa cylinder instead of the inner diameter of the cylinder.
To see the pressure gauge is arranged in what position, the general pressure gauge installed in the hydraulic station exit, that is the pressure of the hydraulic system;
No, you want the workpiece to be the force, and the pressure gauge shows the pressure. F=PXS. If ventilation occurs, the cylinder bore and air pressure need to be recalculated.
if you want to change into the cylinder pressure, enough on the line, in addition to consider increasing the oil return pipe of the cylinder, pneumatic actuator only because the system did not return with an air inlet pipe. The trachea.