CONTROL-SYSTEM CAPABLE OF GRACEFULLY DEGRADED OPERATION FOR THE 750 MEV SYNCHROTRON-RADIATION SOURCE

A control system which is capable of gracefully-degraded operation for the 750 MeV electron storage ring as a dedicated VUV (vacuum-ultra-vi olet) 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 la yers, the control system was designed to be reconfigurable. Under norm al operation, the distributed control system is configured so that two process computers control the storage ring cooperatively with full th roughput. If a failure occurs in one computer, the control system is r econfigured so that the remaining functional computer can provide grac efully degraded operation to resume control of the storage ring for sy nchrotron radiation experiments. The control system automatically oper ates the storage ring with a single action on a menu initiated by an o perator. Operational experience has shown that the control system can successfully operate the storage ring.