Control System Reconstruction for 4W1 Magnet Power Supply in BEPC

4W1 magnet in BEPC for Synchrotron Radiation X-Ray beam lines consists of main resistance winding and auxiliary resistance winding which are respectively powered by two independent power supplies with high precision. These two power supplies called main power supply and auxiliary power supply are rebuilt with a new interface PSI (power supply interface). They are controlled by a PSC (power supply controller). This system is completed within one month after the control prototype for BEPC II magnet power supplies with PSC/PSI has been finished. During the beginning of this system running, it is modified many times to meet its operation requirements. It has been running for about four months without big problems so that it ensures synchrotron radiation research on the two X-ray beam lines. This paper describes a new control system based on EPICS for 4W1 magnet power supplies. The requirements to 4W1 magnet ramp and its ramp programming are also discussed.