The MAST data acquisition system - system architecture

A new data acquisition (DA) system has been developed for the MAST experime nt at Culham. It has also been implemented on the COMPASS experiment as a r eplacement for the old PDP-11 based data acquisition system and as a test b ed for MAST. The DA system is distributed across a number of computers with a DA process for each distinct diagnostic system. An object-orientated app roach is taken to the control and readout of each device in the system. It is designed to be independent of the hardware interfaces used on each diagn ostic. The system is flexible enough to cope with diagnostics ranging from those involving simple time evolving signals to complex spectrometers, and will incorporate a new high speed distributed timing system. This system is also being considered as the interface to the real time Plasma Control sys tem on MAST. A distributed scheduling system is used to co-ordinate the act ivity of each DA process with the Central Control system for each experimen t. This paper describes the architecture of this data acquisition system wi th particular emphasis on the core of the data acquisition system. Aspects of distributed implementation of the system on real diagnostics are discuss ed in a companion paper [1]. (C) 2000 Elsevier Science S.A. All rights rese rved.