  CERN is now setting up String 2, a full-size prototype of a regular cell of
the LHC arc. It is composed of two quadrupole, six dipole magnets, and a
separate cryogenic distribution line (QRL) for the supply and recovery of the
cryogen. An electrical feed box (DFB), with up to 38 High Temperature
Superconducting (HTS) leads, powers the magnets. About 700 sensors and
actuators are distributed along four Profibus DP and two Profibus PA field
buses. The process automation is handled by two controllers, running 126 Closed
Control Loops (CCL). This paper describes the cryogenic control system,
associated instrumentation, and their commissioning.
