T.Korhonen, M.Heiniger (PSI)
The timing system of the Swiss Light Source is based on the event system concept of APS, Argonne . However, for SLS the hardware was completely redesigned while preserving the software compatibility with the APS system. This gave us a head start in the implementation: we could use the latest available hardware and take advantage of the features integrated in the EPICS software. The event system is used as the sole timing distribution method, for hardware trigger delivery (assisted with a high-precision delay at a few places) and for controlling all the timing-related tasks of operation: injector sequencing, filling patterns, software synchronization, timestamps and so on. The event network is also extended to the beamlines to allow synchronization of the beamline experiments. The implementation consists of the hardware (Gigabit Ethernet link, FPGAs) and a firmware core written in VHDL. The functionality of the cards can be modified in situ by rewriting the firmware in flash memory. On the other hand, the functionality can be easily ported to new hardware architectures, allowing smooth upgrade paths and maximal reusability of the soft- and hardware resources.
 F.R.Lenkszus et.al., 'The Advanced Photon Source Event System', Proc. ICALEPCS'95
Last updated: September 13, 2002
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