Abstract
The Large Hadron Collider (LHC) at CERN in Geneva, Switzerland, has just completed the Run 2 era, colliding protons at a center-of-mass energy of 13 TeV at high instantaneous luminosity. The Compact Muon Solenoid (CMS) is a general-purpose particle detector experiment at the LHC. The CMS electromagnetic calorimeter (ECAL) has been designed to achieve excellent energy and position resolution for electrons and photons. A multi-machine distributed software configures the on-detector and off-detector electronic boards composing the ECAL data acquisition (DAQ) system and follows the life cycle of the acquisition process. Since the beginning of Run 2 in 2015, many improvements to the ECAL DAQ have been implemented to reduce and mitigate occasional errors in the front-end electronics and not only. Efforts at the software level have been made to introduce automatic recovery in case of errors. Automatic actions has made even more important the online monitoring of the DAQ boards status. For this purpose a new web application, EcalView, has been developed. It runs on a light Node.js JavaScript server framework. It is composed of several routines that cyclically collect the status of the electronics. It display the information when web requests are launched by client side graphical interfaces. For each board, detailed information can be loaded and presented in specific pages if requested by the expert. Server side routines store information regarding electronics errors in a SQLite database in order to perform offline analysis about the long term status of the boards.
Highlights
The Compact Muon Solenoid (CMS) is a multipurpose detector designed for the precision measurement of leptons, photons, and jets, among other physics objects, in proton-proton as well as heavy ion collisions at the Large Hadron Collider (LHC) [1]
The consequence is an error in the electronic board and the stop of the data flow from the sector associated with the affected Data Concetrator Card (DCC)
The DCC Supervisors publish the detail of the events (SEUs and channels masked) on the flashlist and the Monitor Logic can retrieve them with two consequences: they are saved in the database for future tracking and they are directly displayed on the error tables
Summary
The Compact Muon Solenoid (CMS) is a multipurpose detector designed for the precision measurement of leptons, photons, and jets, among other physics objects, in proton-proton as well as heavy ion collisions at the LHC [1]. The main task of the DAQ online software is the control of the readout electronics It configures the electronics (off and on-detector) with the parameters required to tune the data taking. It sends control commands to the Finite State Machine (FSM) of the boards’ firmware It integrates the ECAL sub-system in the CMS Trigger and DAQ system (TriDAS) [4]. The HAL library can instantiate a VMEDevice object that represents virtually an electronic card and it can perform read and write operations on the hardware registers (Figure 2)
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