Update of power supply control system at the SAGA Light Source storage ring

The control system for the SAGA Light Source storage ring power supplies is being upgraded to increase the ramp-up speed and allow the stored beam energy to be easily changed. By replacing the CPU module in the PLC used to control the power supplies, the ramp-up time was reduced from 4 to 2 minutes in a test bench prepared for the upgraded system. Until now, the allowable beam energy has been restricted to certain fixed values during ramp-up operation due to the original specifications of the PLC ladder program. To operate the storage ring at an arbitrary energy, the algorithm used in the PLC program was changed. The resolution at which the energy can be changed is less than 1 MeV. The upper layer of the control system, which uses National Instrument LabVIEW and ActiveX CA, was also reconstructed to produce a flexible GUI. Preliminary measurements of the energy dependence of the beam size and lifetime were carried out using the updated control system. (author)