ARCHITECTURE OF THE LEP2 CRYOGENICS CONTROL-SYSTEM - CONCEPTION, STATUS, AND EVALUATION

Conception and realisation of the industrial process control system an d application programs for the four new 12 kW/4.5K cryoplants, and the 192 superconducting accelerating cavities, were critical activities i n the implementation of the cryogenic system for the LEP2 project at C ERN. The main objectives like regulation quality, automatic restarts, centralised remote control, homogenisation of the logics for the cryop lants built by different suppliers are exposed as well as the current state of advancement. The modular distributed control system hardware is presented. The architecture of software using an object oriented pr ogramming method is described. A tentative evaluation is presented wit h a general view on work and costs, from which follow conclusions conc erning future control systems for similar projects.