  This paper describes the CERN's vacuum control system from the field devices
to the Supervisory Control and Data Acquisition software. First, a particular
attention is given to the environment present in the accelerators, like noise
coupling and ionizing radiation, which can affect the quality of the
measurements and the reliability of the system. Then, the main vacuum
instruments and their associated conditioning circuits and controllers are
presented, before to introduce the hardware interlock logic and alarms used for
the vacuum system and the machine protection. Finally, the Supervisory Control
and Data Acquisition software and its architecture are described, including
data engineering and the main functionalities provided to the users for
controls and diagnostics.
