Computer control system of PLS 2-GeV storage ring

A real-time computer control system has been developed and is used for the precise remote operation of the Pohang Light Source (PLS) 2-GeV storage ring. It consists of three layers of computer systems: console computer for operator interface, subsystem control computer (SCC) for front-end data processing, machine interface unit (MIU) for low-level data acquisition. The console computer is a Sun Microsystem's SPARC station with UNIX. It uses X-Window/Motif for the GUI (graphic user interface) tool. The SCC acts as a front-end data processing between the console computer and the MIU. There are 24 MIUs placed in the storage ring building. The MIU is directly connected to individual machine components to do low-level data acquisition. The SCC and MIU are based on VMEbus standard and use Microware's OS-9 real-time operating system. Console-computers and SCCs are connected through Ethernet (TCP/IP). SCCs and MIUs are connected through MIL-STD-1553B fieldbus. This paper presents general hardware and software structures of the control system.