Author: Leban, P.
Paper Title Page
WEPME037 Fast Orbit Feedback at Taiwan Photon Source 3007
  • A. Bardorfer, P. Leban
    I-Tech, Solkan, Slovenia
  • P.C. Chiu, K.T. Hsu, C.H. Kuo
    NSRRC, Hsinchu, Taiwan
  Low latency, distributed, Fast Orbit Feedback (FOFB) application, based on singular value decomposition, entirely implemented in FPGA, has been developed for the Taiwan Photos Source (TPS). The FOFB utilizes the latest Libera Brilliance+ units for measuring beam position and the Gigabit Data eXchange (GDX) modules, which take care of global orbit distribution via 6.5 Gbit/s fiber optic or passive Cu links, and provide a large orbit data history buffer. The magnet correction in a matrix form of M = V . PI( S-1 . UT . ( Golden-Orbit ) ) is calculated entirely in FPGA, using a massively parallel approach and sent to the magnet power supplies via 2.5 Gbit/s link. The entire FOFB calculation is distributed over 48 GDX modules and the system allows for synchronous (on/off/pause) FOFB control via external input signal. The latencies of 60 ns per BPM for orbit distribution, 1.5 us for FOFB calculation and 1.5 us for magnet data transmission have been measured at TPS test installation in November 2012. The expected total communication and FOFB calculation latency in the TPS final configuration (168 BPMs) is expected to stay within 15-20 us range.