1. F.Carena, CERN/ALICE The ALICE Experiment Control System F. Carena / CERN-PH

2. F.Carena, CERN/ALICE 2 10 October 2005, ICALEPCS 2005, Geneva Introduction uALICE (A Large Ion Collider Experiment) is the heavy-ion experiment being prepared for the Large Hadron Collider (LHC) at CERN

3. F.Carena, CERN/ALICE 3 10 October 2005, ICALEPCS 2005, Geneva Introduction uALICE consists of many particle detectors that can be operated:  All together to collect experimental data  As standalone, independent objects In the present test and commissioning phaseIn the present test and commissioning phase In the future, final setup for calibration and test purposesIn the future, final setup for calibration and test purposes uRunning the experiment implies performing a set of activities on the detectors. These activities belong to different domains:  Detector Control System (DCS)  Data Acquisition (DAQ)  Trigger system (TRG)  High Level Trigger (HLT) uEvery domain of activities requires some form of control  In ALICE independent ‘online systems’ have been developed to control the different domains

4. F.Carena, CERN/ALICE 4 10 October 2005, ICALEPCS 2005, Geneva Introduction uThe existing, independent ‘online systems’  Operate with all the detectors  Allow partitioning (partitioning is the capability to concurrently operate groups of ALICE detectors) uThe Experiment Control System (ECS) must coordinate the operations controlled by the ‘online systems’ for every detector in every partition uThe ECS is a layer of software on top of the existing ‘online systems’. It gets status information from the ‘online systems’ and sends commands to them through interfaces based on Finite State Machines (FSM) uAccess control mechanisms in the interfaces manage the ECS rights  ‘online systems’ under the ECS control  ‘online systems’ operated as independent systems

5. F.Carena, CERN/ALICE 5 10 October 2005, ICALEPCS 2005, Geneva Partitions uA partition is a group of detectors identified by a name and defined by:  A list of ’assigned’ detectors. It contains the names of the detectors that can be active in the partition  A list of ‘excluded’ detectors. It contains the names of the detectors that are assigned to the partition but are not active (active in another partition, operated in standalone mode, or because of explicit operator request) u Two types of operations are possible within a partition:  Global operations involving all the active detectors  Individual detector operations involving one single detector Individual detector operations can be concurrently performed within a partition (e.g. parallel calibration procedures of different detectors)Individual detector operations can be concurrently performed within a partition (e.g. parallel calibration procedures of different detectors) uGlobal and individual detector operation are mutually exclusive

6. F.Carena, CERN/ALICE 6 10 October 2005, ICALEPCS 2005, Geneva Partitions uThe handling of global operations in a partition requires the coordination of  the DCS for all the active detectors  the DAQ Run Control that steers the data acquisition for the partition  the Trigger Partition Agent (TPA) that connects the partition to the Central Trigger Processor (CTP) DCS_1 TPA DAQ_RC DCS_2 DCS_3

7. F.Carena, CERN/ALICE 7 10 October 2005, ICALEPCS 2005, Geneva Partitions uThe handling of an individual detector operation in a partition requires the coordination of  the DCS for one detector  the DAQ Run Control that steers the data acquisition for the detector  the Local Trigger Unit (LTU) associated to the detector DCS LTU DAQ_RC

8. F.Carena, CERN/ALICE 8 10 October 2005, ICALEPCS 2005, Geneva Standalone detectors uA standalone detectors is a detector operated  out of all the defined partitions  totally disconnected from the Central Trigger Processor (CTP) uThe handling of a standalone detector requires the coordination of  the DCS for the detector  the DAQ Run Control that steers the data acquisition for the detector  the Local Trigger Unit (LTU) associated to the detector DCS LTU DAQ_RC

9. F.Carena, CERN/ALICE 9 10 October 2005, ICALEPCS 2005, Geneva Components uThe main components of the ECS are the Partition Control Agent (PCA), the Detector Control Agent (DCA), the PCA Human Interface (PCAHI), and the DCA Human Interface (DCAHI) uThere is one PCA per partitions.  Handles global operations in the partition  Delegates individual detector operations to the DCAs  Handles the structure of the partition (inclusion/exclusion of detectors)  Accepts commands from one PCAHI at a time PCAHI Master Operator PCAHI PCA

10. F.Carena, CERN/ALICE 10 10 October 2005, ICALEPCS 2005, Geneva Components uThere is one DCA per detector  When the detector is in standalone mode Handles standalone operationsHandles standalone operations Accepts commands from a DCAHI at atimeAccepts commands from a DCAHI at atime  When the detector is active in a partition Handles individual detector operations within the partitionHandles individual detector operations within the partition Accepts commands from the PCA onlyAccepts commands from the PCA only PCAHI Master Operator DCA PCA DCAHIDCAHI DCA DCAHI

11. F.Carena, CERN/ALICE 11 10 October 2005, ICALEPCS 2005, Geneva DCA Human Interface

12. PCA Human Interface

13. F.Carena, CERN/ALICE 13 10 October 2005, ICALEPCS 2005, Geneva Architecture uExample of architecture with 3 detectors (SDD, SPD, and SSD)  The SDD detector is operated in standalone mode  SPD and SSD are active in a partition called ITS

14. F.Carena, CERN/ALICE 14 10 October 2005, ICALEPCS 2005, Geneva Interfaces uThe components of the ECS get status information from the ‘online systems and send commands to them through interfaces based on Finite State Machines (FSM) uThe FSM package used for these interfaces is SMI++  http://www.cern.ch/smi uThe interfaces also contain access control mechanisms that allow to control the rights granted to the ECS. The ‘online systems’ can be under the control of the ECS or be operated as independent systems: in this case the ECS get status information but does not send commands

15. F.Carena, CERN/ALICE 15 10 October 2005, ICALEPCS 2005, Geneva ECS/DCS interface

16. F.Carena, CERN/ALICE 16 10 October 2005, ICALEPCS 2005, Geneva ECS/TRG interface

17. F.Carena, CERN/ALICE 17 10 October 2005, ICALEPCS 2005, Geneva ECS/DAQ, ECS/HLT interfaces uThe interface between the ECS and the DAQ is made of SMI objects representing Run Control processes  An RC process per detector. Every RC process steers the data acquisition for a given detector and for that detector only  An RC process per partition to steer the data acquisition for the whole partition with data produced by all the active detectors u The ECS gets status information through a single SMI object representing the HLT ‘online system’ as a whole.

18. F.Carena, CERN/ALICE 18 10 October 2005, ICALEPCS 2005, Geneva ITS combined test uIn October 2004 the ECS has been used to control the combined test of the ALICE Inner Tracking System consisting of  3 detectors Silicon Drift Detector (SDD)Silicon Drift Detector (SDD) Silicon Pixel Detector (SPD)Silicon Pixel Detector (SPD) Silicon Strip Detector (SSD)Silicon Strip Detector (SSD)  Trigger System 3 LTUs3 LTUs Special version of the TPASpecial version of the TPA  DAQ System 4 independent data acquisitions4 independent data acquisitions  Dummy DCS system for the 3 detectors

19. F.Carena, CERN/ALICE 19 10 October 2005, ICALEPCS 2005, Geneva ITS test setup SDDSPDSSD LDC LDCLDC GDC CONTROL Fast Ethernet DDLDDLDDL Localdisks SDD-LTUSPD-LTUSSD-LTU TPA DAQ runControl processes ECS processes (PCA+DCAs)

20. F.Carena, CERN/ALICE 20 10 October 2005, ICALEPCS 2005, Geneva Results uAll the possible modes of operation were successfully tested  3 detectors in standalone mode  Any combination of 2 detectors running together and the 3 rd one in standalone mode  3 detectors running together uSwitching from a mode of operation to another was  Fast (a few seconds)  Totally transparent for the DAQ and the TRG ‘online systems’

21. F.Carena, CERN/ALICE 21 10 October 2005, ICALEPCS 2005, Geneva Conclusion uThe ECS has been intensively developed during the last 18 months uThe architecture and the interfaces have been implemented and successfully tested during the ITS combined test beam uSome developments are still needed  Several detectors have not yet implemented a DCS based on FSM and therefore the DCS states are not yet included in the ECS  Some detectors have not yet developed their calibration procedures  Some information like the definition of the Trigger classes is not available yet (temporary definition used for the time being) uThe above issues will be included as soon as available. The ECS architecture has been proved to be solid and flexible enough to include all the future extensions.