The Control System for the Cryogenics in the LHC Tunnel [ First Experience and Improvements ]
A.Tovar, C.Fluder, E.Blanco, G.Penacoba, J.Casas, L.Zwalinski, M.Pezzetti, M.Soubiran, P.Gomes* (CERN)
The Large Hadron Collider (LHC) has been commissioned and started operation with beams in 2008, at CERN. Several months of cryogenic operation in nominal conditions have triggered an optimisation of the cryogenic process functional analysis. This lead to a few revisions of the control logic, realised on-the-fly; and to a major rebuild of the logic, implemented during the 2008-9 shut-down. In order to improve the operability, availability and safety of the LHC cryogenics, the process control structure was reorganised; the logic of process phases, interlocks, regulators and templates for automatic code generators were modified; the hard-wired vacuum-quality signals were upgraded to provide more detailed information; the protection of current feed boxes was enhanced by the addition of new signals; a new tool for remote-reset of Profibus-IO was developed. The databases, containing all instruments and controls information, were rationalized; the automatic specification generators, which extract the parameters used in the control software, were simplified. This paper describes the main improvements applied during the 2008-09 shut-down, and suggests perspectives of further developments.