Status Report of the Measurement Service for the CERN Accelerator Logging

The LHC (Large Hadron Collider) Logging service is aimed to satisfy the requirement of capturing and storing any relevant accelerator data to track its variation over time. This service is presently operational on the whole CERN accelerator complex, from ion and proton sources to LHC, and has become a critical component of the CERN control systems. The focus is given to the measurement part of this service, which is responsible for the data acquisition and preparation (processing, filtering, concentration) prior to its storage in database and file systems. Incoming data is often processed by a concentration layer, the processes that transform data of multiple devices into single values according to well defined rules and then publish them further on, to the LHC Logging among others. The paper describes the architecture and presents the solutions to the very challenging requirements imposed by the LHC in terms of overall performance and reliability. The efficiency of the data acquisition and filtering as well as the flexible software design are highlighted.