The CMS ECAL Control and Safety Systems Upgrades During the CERN LHC Long Shutdown 2

The Electromagnetic Calorimeter (ECAL) is one of the sub-detectors of the Compact Muon Solenoid (CMS), a general-purpose particle detector at the CERN Large Hadron Collider (LHC). The CMS ECAL Detector Control System (DCS) and the CMS ECAL Safety System (ESS) have supported the detector operations and ensured the detector’s integrity since the CMS commissioning phase, more than 10 years ago. Over this long period, several changes to both systems were necessary to keep them in-line with current hardware technologies and the evolution of software platforms. The acquired experience of long-term running of both systems led to the need of major modifications to the original design and implementation methods. Such interventions to either systems, which require mid- to long-term validation, result in a considerable amount of downtime and therefore can only be performed during long LHC shutdown periods. This paper discusses the software and hardware upgrades to be carried out during the LHC Long Shutdown 2 (LS2), with emphasis on the evaluation of design choices concerning custom and standard industrial hardware.