  By the end of the nineties, the power converter control system (Mugef) of the
CERN proton accelerator (SPS) had undergone a complete modernization. This
resulted in newly developed hardware for function generation, measurement and
I/O in a VME environment, under the LynxOS real-time operating system. This has
provided a platform on which extensions can be developed for future operation
in the Large Hadron Collider (LHC) era. This paper describes some of these
extensions, in particular a fast Surveillance and Interlock system for
monitoring the power converter output currents. This will be mandatory for the
safe operation of the SPS transfer lines TI2 & TI8 to LHC and for similar
applications in the future. The strategies employed to cope with various
failure modes of the power converters and the timely activation of the
interlock are outlined. The new SPS controls infrastructure now under
development, will give rise to new modes of operation for the Mugef systems.
Integration with the proposed middleware must be undertaken in a structured
evolution, while retaining compatibility with the current usage.
