LHC Gas Control System

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

2. Outline • Introduction and working philosophy • Control architecture • Operation • Interactions and Gas systems • Who is doing what? • Conclusions ALICE DCS day

3. Introduction and working philosophy • Synthesize commonalities of proposed gas systems.  Modules: Mixer, Purifier… • URD with detailed descriptions of processes • Design document with engineering issues • Produce PLC code and test on real gas-HW • Instantiate modules for a sub-detector • Assembly and commissioning with detector experts ALICE DCS day

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

5. Operation(1/2) - 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 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: • 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. The normal experiment shifter can launch this procedure and only if it is not successful a gas piquet will be called. ALICE DCS day

6. Operation(2/2) - Operators • Observerscan view everything but cannot change parameters. • Gas maintenance operatorscan bring modules into “Test-State”, inhibit alarms, etc… • Gas operator can issue commands like start, stop, recover from power-cut, etc… no parameter changes, though. Shifters profile. • Gas expertshave full access to all parameters and commands • Gas system developers can even change programs… ALICE DCS day

7. Experiment Control System Shifter ALICE Gas Piquet Status Status Sub-Detector Control System ATLAS PVSS PVSS PVSS HMI HMI HMI GASControl System CMS LHCb EV EV EV Shifter, Gas expert, etc Status driver driver driver HMI HMI HMI Sub detector expert ALICE DCS day

8. CMS DT Gas Control System Gas Control System Mixer Gas Control System Mixer Argon Run-MFC X _ Gas Control System DT X X _ _ X _ CMS CSC Digital Mass Flow Controller CMS RPC Primary supply Mixer Purifier Analysis Location : SG15, rack 7890 Actual set point : 540.0 l/h Measured flow : 0.0 l/h Calibration : Argon Totalizer : 345.6 m3 Communication : etc.. Totem CSC Totem RPC Distribution US UX YB2 YB2 YB1 YB1 Analysis Pump YB0 YB0 failure Alarm messages YB-1 YB-1 15:41:22 3.6.2007 | Argon Run-MassFlowController is not responding YB-2 YB-2 Use case : faulty device CMS DT ALICE DCS day

9. CMS DT Gas Control System X _ Gas Control System DT X _ CMS CSC CMS RPC Primary supply Mixer Purifier Analysis Totem CSC Gas Expert Schaefer is logged in Totem RPC Distribution US UX User : Schaefer Password: ******** Commands YB2 YB2 Login Start Stop Recover Change recipe Clear alarms Change sequ. Login YB1 YB1 MFC in use : MFC #1 Calibration : Argon Warning limit : +/- 0.5% Alarm limits : +/- 0.8% Alarm action : GotoStopCommand etc… Analysis Pump Run Fill Purge YB0 YB0 Top Mixer Purifier Distrib. Pump Top Mixer Purifier Distrib. Pump Change recipe YB-1 YB-1 YB-2 YB-2 Use case : Problem solving Mixer Login Start Stop Recover MFC #2 ALICE DCS day

10. Example of remote operation • Standard Mixer • http://lhcexp.web.cern.ch/LHCExp/GasWG/standard_mixer • NEITHER the programming tool NOR the architecture is the final one !!! • Only the control philosophy should be observed • Any future gas control project will be written in PVSS. We started already with purifier and mixer module…. • Many of our gas users ask for web-interfaces for monitoring and control. Will this be available? ALICE DCS day

11. Interactions with Gas Control System (GCS) • GCS DCS • Status, alarms, events of each sub-detector • Any other information the sub-detector experts may want to access: chamber pressures, main flows, impurities, etc.. (needs to be defined) • GCS DSS • Under discussion at the moment • for HV interlocks we can provide hardwired or software signals ALICE DCS day

12. Who is doing what? • Detector experts: • gas requirements at the beginning • TA1-GS: • Gas hardware racks • Organisation of all necessary software parts • IT/CO: • Building blocks of all modules involved. On PLC and on supervision level with clear deliverables. • Instantiate and test first gas systems (help needed for ALL) • ALL together: • commissioning of gas system at sites • determine the best set of parameters with the detector experts • determine start-up and shutdown procedures, etc ALICE DCS day

13. Conclusions • The gas group will be part of the operation team that will be responsible for running an experiment • There will be NO read restrictions to any user profile. Write access will be restricted to “Gas Expert” profiles. • For the central gas team it is favourable to interact with all gas systems of one experiment from a single workstation. This is, however, not in contradiction with accessing gas information from a sub-detector control system. ALICE DCS day