The timing system for the ASDEX Upgrade experiment control

For the adaptive control system of the ASDEX Upgrade tokamak experiment a new digital timing system was developed. Its structure is centralized and distributed. The timing system defines a systemwide 100-ns absolute timescale by central generation of clock and time zero information. Distributed processes are synchronized by time events and state events generated centrally. The timing system supports preprogrammed operation and adaptive operation in close collaboration with the central control computers. A summary is presented of the ASDEX Upgrade timing system design and implementation and of aspects of the integration into the control system. >