Application of PLC in transformation of control system of hydraulic machine and control of analog variable

YA32-315 as four-column type hydraulic press was changed from relay control to the programmable logic controller(PLC)control.Original control system of the hydraulic oil system of liftout cylinder was transformed.The oil pressure was controlled by the high accuracy proportional spillover valve and the analog I/O model of the PLC.With the deep drawing process of sheet metal the variable blank-holder force control was realized on the single-action hydraulic machine.The forming force,the black-holder force and the punch stroke were monitored and controlled in real time in the sheet metal forming process by the programmable Terminal(PT).