The Evolution of the CERN SPS Timing System for the LHC Era

The SPS is the last machine in the LHC injector chain; however, it will be difficult in the LHC era to treat it like the other lower energy multi-cycling machines. Not only is there a huge amount of legacy hardware and software, but due to machine physics constraints, it is doubtful that it would ever be possible for the SPS to truly multi-cycle in the PS sense. Today, the SPS control system regularly performs super-cycle changes in an average time of 20 minutes, but then setting the beams up afterwards takes longer. We expect many more SPS super-cycle changes per day in various LHC filling scenarios, and machine developments, and hence any savings we can make in SPS super-cycle switch-over time will not only better exploit the PS complex, but will also provide more SPS beam for other users. Centrally coordinated sequence changes make obvious gains for physics, but also, the cost benefits of a uniform approach to controls have been identified elsewhere. This paper will discuss the planned central-timing due to come online in November 2003.