Author: Schwemmer, R.
Paper Title Page
MOBAUST06 The LHCb Experiment Control System: on the Path to Full Automation 20
  • C. Gaspar, F. Alessio, L.G. Cardoso, M. Frank, J.C. Garnier, R. Jacobsson, B. Jost, N. Neufeld, R. Schwemmer, E. van Herwijnen
    CERN, Geneva, Switzerland
  • O. Callot
    LAL, Orsay, France
  • B. Franek
    STFC/RAL, Chilton, Didcot, Oxon, United Kingdom
  LHCb is a large experiment at the LHC accelerator. The experiment control system is in charge of the configuration, control and monitoring of the different sub-detectors and of all areas of the online system: the Detector Control System (DCS), sub-detector's voltages, cooling, temperatures, etc.; the Data Acquisition System (DAQ), and the Run-Control; the High Level Trigger (HLT), a farm of around 1500 PCs running trigger algorithms; etc. The building blocks of the control system are based on the PVSS SCADA System complemented by a control Framework developed in common for the 4 LHC experiments. This framework includes an "expert system" like tool called SMI++ which we use for the system automation. The full control system runs distributed over around 160 PCs and is logically organised in a hierarchical structure, each level being capable of supervising and synchronizing the objects below. The experiment's operations are now almost completely automated driven by a top-level object called Big-Brother which pilots all the experiment's standard procedures and the most common error-recovery procedures. Some examples of automated procedures are: powering the detector, acting on the Run-Control (Start/Stop Run, etc.) and moving the vertex detector in/out of the beam, all driven by the state of the accelerator or recovering from errors in the HLT farm. The architecture, tools and mechanisms used for the implementation as well as some operational examples will be shown.  
slides icon Slides MOBAUST06 [1.451 MB]  
MOPMN019 Controling and Monitoring the Data Flow of the LHCb Read-out and DAQ Network 281
  • R. Schwemmer, C. Gaspar, N. Neufeld, D. Svantesson
    CERN, Geneva, Switzerland
  The LHCb readout uses a set of 320 FPGA based boards as interface between the on-detector hardware and the GBE DAQ network. The boards are the logical Level 1 (L1) read-out electronics and aggregate the experiment's raw data into event fragments that are sent to the DAQ network. To control the many parameters of the read-out boards, an embedded PC is included on each board, connecting to the boards ICs and FPGAs. The data from the L1 boards is sent through an aggregation network into the High Level Trigger farm. The farm comprises approximately 1500 PCs which at first assemble the fragments from the L1 boards and then do a partial reconstruction and selection of the events. In total there are approximately 3500 network connections. Data is pushed through the network and there is no mechanism for resending packets. Loss of data on a small scale is acceptable but care has to be taken to avoid data loss if possible. To monitor and debug losses, different probes are inserted throughout the entire read-out chain to count fragments, packets and their rates at different positions. To keep uniformity throughout the experiment, all control software was developed using the common SCADA software, PVSS, with the JCOP framework as base. The presentation will focus on the low level controls interface developed for the L1 boards and the networking probes, as well as the integration of the high level user interfaces into PVSS. We will show the way in which the users and developers interact with the software, configure the hardware and follow the flow of data through the DAQ network.