Control system capable of gracefully degraded operation for the 750 MeV synchrotron radiation source

A control system which is capable of gracefullydegraded operation for the 750 MeV electron storage ring as a dedicated VUV (vacuum-ultra-violet) synchrotron radiation source at the UVSOR has been developed to provide a synchrotron radiation beam for a long time without any fatal shutdown. Based on a client-server model with a hierarchy of three layers, the control system was designed to be reconfigurable. Under normal operation, the distributed control system is configured so that two process computers control the storage ring cooperatively with full throughput. If a failure occurs in one computer, the control system is reconfigured so that the remaining functional computer can provide gracefully degraded operation to resume control of the storage ring for synchrotron radiation experiments. The control system automatically operates the storage ring with a single action on a menu initiated by an operator. Operational experience has shown that the control system can successfully operate the storage ring.