Epics/rtems/mvme5500 for Real-time Controls at Nsls

At several National Synchrotron Light Source (NSLS) beamlines, open source control systems offer a modern solution for cost effectiveness and technical competence. The "Experimental Physics and Industrial Control System" (EPICS) [1] and the "Real-Time Operating System for Multiprocessor Systems" (RTEMS) [2][3] were chosen to constitute the core control system. A RTEMS Board Support Package (BSP) for the Motorola PowerPC MVME5500 board was written at NSLS [4][5]. RTEMS device drivers for a PMC2343 IEEE1394 (firewire) adapter and RTEMS libraries for IIDC 1394-based digital cameras were also written in house to be incorporated with EPICS video software [6] to provide inexpensive yet high-end image processing. As of today, the EPICS/RTEMS/MVME5500 control system is implemented at several NSLS beamlines for real-time experiments. The RTEMS/MVME5500 BSP has been adapted at other facilities for accelerator and industrial real-time controls. The control system in use at these NSLS beamlines, and its performance, will be presented. INTRODUCTION There are over two thousands users of NSLS at BNL yearly. At several NSLS beamlines, EPICS as core control software and RTEMS as real-time Operating System (O.S.), both of them open source, were adapted to produce low-cost and robust VME control systems. Recently, Nobel Prize winning research was performed at one of NSLS beamlines, which utilize the EPICS/RTEMS/MVME2307 control systems. The Motorola PowerPC MVME2307 board was discontinued as of September 2003, which led us to a decision of developing a RTEMS BSP for the high-performance and cost-effective Motorola PowerPC MVME5500, which has a long-lived roadmap. The architecture of its system controller GT64260 is similar to that of GT64360, which offers off-the-shell embedded solutions on the VME/VXS platform (e.g. VPF1 or MVME6100 on 2eSST VME) for fast I/O on the custom hardware. Thus, some of the BSP software would become sharable for the planned embedded solutions. The technical comparison listed in the next section has proven that the real-time performance of the EPICS/RTEMS/MVME5500 is comparable to that of vxWorks, a leading commercial real-time O.S.. The 1GHZ processor speed and high network throughputs of the MVME5500 offer users the advantage to integrate the RTEMS based real-time image processing software written at NSLS into the EPICS/RTEMS Input Output Controllers (IOCs), which further cut the system cost yielding compact, flexible and optimal real-time control systems. PERFORMANCE MEASUREMENT The following subsections present the network and latency performance comparison between RTEMS and vxWorks on the MVME5500.