1. LHC Gas Control System Stefan Haider EP-TA1-GS

2. 16.6.2003ALICE DCS workshop, S.Haider2 Outline Introduction and working philosophyIntroduction and working philosophy Control architectureControl architecture OperationOperation Hierarchies (bubble diagrams)Hierarchies (bubble diagrams) Information exchangeInformation exchange Who maintains what?Who maintains what? ConclusionsConclusions

3. 16.6.2003ALICE DCS workshop, S.Haider3 Working philosophy for Gas System Controls Synthesize commonalities of proposed gas systems.  Modules: Mixer, Purifier…Synthesize commonalities of proposed gas systems.  Modules: Mixer, Purifier… URD with detailed descriptions of processesURD with detailed descriptions of processes Design document with engineering issuesDesign document with engineering issues Produce PLC code and test on real gas-HWProduce PLC code and test on real gas-HW Instantiate modules for a sub-detectorInstantiate modules for a sub-detector Assembly and commissioning with detector expertsAssembly and commissioning with detector experts

4. 16.6.2003ALICE DCS workshop, S.Haider4 Control architecture UX Plug Surface bldg. Control room Main PLC Ethernet ProfiBUS CPU I/O modul ADC DAC DI/O PBusADC DAC DI/O PBus Device ProfiBUS coupler ProfiBUS Ethernet CAN-bus ProfiBUS CPU I/O modul ADC DAC DI/O PBusADC DAC DI/O PBus Device PLC ProfiBUS ELMB P CAN-bus CERN / Experiment Ethernet Operator workstations

5. 16.6.2003ALICE DCS workshop, S.Haider5 Operation (1/3) - General Aspects The gas maintenance group will be part of the operation team of an experiment. Like experts of any other sub-system, we shall report about gas to the team leaders.The gas maintenance group will be part of the operation team of an experiment. Like experts of any other sub-system, we shall report about gas to the team leaders. The Gas Control System of an experiment must be kept independent of other sub-systems as much as possible, because –The Gas Control System of an experiment must be kept independent of other sub-systems as much as possible, because – –the gas systems startup about 3 weeks earlier than other system –and the maintenance crew must find similar environments coming from one experiment to the next During running periods, Gas Piquets will support the experiments:During running periods, Gas Piquets will support the experiments: –90% of all piquet-interventions at LEP was restarting the gas systems after a power-cut. –Now, the control system will handle this with the “Recover from Power-cut” procedure. Stability:Stability: –Changes of parameters are rare, and reserved for sub-detector gas experts

6. 16.6.2003ALICE DCS workshop, S.Haider6 Operation (2/3) - Operators DCS shifters will observe the gas systems – –warnings and alarms will be reported to a central place,-- ( ok / not ok information ) – –in case of “not ok”, panel of the gas system can be opened that show a more detailed fault report – –shifter has read-access to all online plots and display panels of all gas system of the experiment DCS shifter can restart a gas system – –after power cuts – –after failure of a part of a sub subsystem

7. 16.6.2003ALICE DCS workshop, S.Haider7 Operation (3/3) - Operators GCS sub-detector expertGCS sub-detector expert –has write access to recipes (running parameters) –can start and stop sub-modules of his gas system GCS gas expertGCS gas expert –has access to all changeable parameters of all gas systems in an experiment Gas System maintenance crewGas System maintenance crew –has limited access to parts of systems that need regular interventions, like O2 cells, etc...

8. 16.6.2003ALICE DCS workshop, S.Haider8 “Reporting/recovery hierarchy” DCS Shifter sees a problem first,DCS Shifter sees a problem first, He calls the sub-detector gas expert, who should be able to resolve most situations.He calls the sub-detector gas expert, who should be able to resolve most situations. Only if he can not find a solution (e.g. faulty equipment, etc.), he will call the “Gas Piquet” from the central Gas Team.Only if he can not find a solution (e.g. faulty equipment, etc.), he will call the “Gas Piquet” from the central Gas Team.

9. 16.6.2003ALICE DCS workshop, S.Haider9 Experiment Control System EV HMI driver Sub -Detector Control System EV HMI driver GAS Control System EV HMI driver Shifter Sub detector expert Shifter, Gas expert, etc Status CMS ATLAS LHCb Gas Piquet Shifter Sub detector expert Shifter, Gas expert, etc

10. 16.6.2003ALICE DCS workshop, S.Haider10 DCS TPCTRDTOF….GAS HVLV Sub-sys. CAEN TPCTRDTOF TPC PLCTRD PLCTOF PLC TPC gas equipment TRD gas equipment TOF gas equipment Gas Bubbles mean information concentration/display

11. 16.6.2003ALICE DCS workshop, S.Haider11 Commissioning of several gas systems at the same time… TPC TRD TOF TPC PLC TRD PLC TOF PLC TPC gas equipment TRD gas equipment TOF gas equipment TPC,TRD,TOF… One PVSS systems for all Gas Systems AFTER commissioning phase… Independent PVSS systems on individual PC’s Pro: - maintenance of one system easier - common devices easier integrated Con: - downtime,- problem for all,  has to be short

12. 16.6.2003ALICE DCS workshop, S.Haider12 Information exchange with the Gas Control System Gas Control System GCS  DCSGas Control System GCS  DCS –Status, alarms, events of each sub-detector GCS  DSSGCS  DSS –Under discussion at the moment Hardwired signals and messages via DIP (or different) are possibleHardwired signals and messages via DIP (or different) are possible GCS  Sub-Detector Control SystemGCS  Sub-Detector Control System –Any other information the sub-detector experts may want to access: chamber pressures, main flows, impurities, etc.. DCS  GCSDCS  GCS –None identified yet ! Input from detector experts welcome.

13. 16.6.2003ALICE DCS workshop, S.Haider13 Who creates/maintains what? Gas group responsible for:Gas group responsible for: –PVSS panels that are necessary to interact with the gas system (main navigation, recipes, download/upload mechanisms, access control, alarm panels etc..) –PLC code. Sub-detectors are responsible for:Sub-detectors are responsible for: –Sub-detector specific PVSS panels: E.g. correlation of gas data with performance dataE.g. correlation of gas data with performance data E.g. safety actions that turn off HV in case gas is not ready for physics.E.g. safety actions that turn off HV in case gas is not ready for physics. Etc..Etc..

14. 16.6.2003ALICE DCS workshop, S.Haider14 Conclusions We see our work as a service to the experiments, with the aim of producing gas systems that can be maintained by one team for the operational period of LHCWe see our work as a service to the experiments, with the aim of producing gas systems that can be maintained by one team for the operational period of LHC Sub detector experts are in full charge of their Gas SystemSub detector experts are in full charge of their Gas System “Crash-resistant” PLC computers will control the gas system hardware,--- NOT PVSS on PC’s (PVSS = user interaction only)“Crash-resistant” PLC computers will control the gas system hardware,--- NOT PVSS on PC’s (PVSS = user interaction only) Displays of gas panels can be installed on any PC at CERNDisplays of gas panels can be installed on any PC at CERN Design of gas control system is not at all frozen…. Looking forward to user input…Design of gas control system is not at all frozen…. Looking forward to user input…