Energy ramping control system for the PLS storage ring

An energy ramping control system was developed for the PLS storage ring. Basically the ramping process is to increase currents of magnet power supplies. But the real process is never easy because of two requirements; fast ramping and keeping the storage ring optics unchanged. To satisfy these requirements, the energy ramping system took full advantage of the three-layered PLS control system. Twelve machine interface units (MIUs) at the bottom layer synchronously control the magnet power supplies. One subsystem control computer (SCC) at the middle layer generates the synchronization signals and sends them to the MIUs for the synchronous control of the magnet power supplies. Operator computer at the top layer does nothing but simply sending ramping start command to the SCC and MIUs. The broadcasting protocol of MIL-1553B is used for the transmission of the synchronization signals from the SCC to the MIUs. Now we can increase 2.0 GeV beam energy to 2.5 GeV in a few minutes with the ramping control system. This paper describes system structure, synchronization scheme, and control software of the PLS energy ramping control system.