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Real Time Measurement and Control at JET Overview & Status

Real Time Measurement and Control at JET Overview & Status. Robert Felton 1 , and JET EFDA Contributors 1 Euratom / UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK.

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Real Time Measurement and Control at JET Overview & Status

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  1. Real Time Measurement and Control at JETOverview & Status Robert Felton1, and JET EFDA Contributors 1 Euratom / UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK This work this work has been performed under the European Fusion Development Agreement. It is funded in part by the United Kingdom Engineering and Physical Sciences Research Council and by EURATOM ICALEPCS 2005 / RTMC at JET / R.Felton

  2. JET = Joint European Tokamak • Fusion plasmas in reactor-relevant conditions • Theory - Deuterium and Tritium easiest to access • D + D = T 1MeV + p 3MeV • D + T = 4He 3.5 MeV + n 14 MeV • temperature 100 M oC, • density 2-3 x 1020 m-3 (1 mg m-3) • confinement > 1s • improved confinement modes • complex interplay of magnetic and kinetic forces • internal and edge instabilities with pressure gradients • short and long range forces: not “classical ideal gas” • Practical - Toroidal Magnetic Confinement • magnetic confinement, shape and current • power loads on vessel components • particle fuelling and exhaust • impurities from plasma-wall interaction ICALEPCS 2005 / RTMC at JET / R.Felton

  3. JET = Joint European Tokamak • Machine Engineering - many and varied issues • vessel toroidal R 3m, r 2m, 200 m3, Inconel • wall CFC tiles (Beryllium and Tungsten coming) • vacuum base 10-8 mBar (cryo), plasma 10-5 mBar • magnets 32 Toroidal, 9 Poloidal, ~ kV, ~ kA • heating NB, 20MW, RF 30MHz 8MW, 3.7GHz 10MW • fuelling 12 gas injectors + pellet; ~500 mBarl per pulse • radiological Biological shield, Tritium compatibility • remote-handling radioactive and toxic (Be) components • diagnostics magnetic, thermal, optical x-ray .. visible, neutronic ... Pulsed ~ 10s 300MJ ICALEPCS 2005 / RTMC at JET / R.Felton

  4. JET = Joint European Tokamak • Systems Engineering - many and varied • machine control • hierarchical, distributed, pulsed • home-grown • real-time communications • analogue, digital signals • data packet networks • operations data • 15000 points, 35000 pulses and growing • data acquisition • 1ns … 1s, nV .. kV, • VME, PCI, CAMAC, PLC • data analysis • traditionally post pulse, • increasingly real-time • remote participation • VRVS ICALEPCS 2005 / RTMC at JET / R.Felton

  5. Tokamak Measurement & Control Hierarchical machine control Systems (vessel, magnets, gas, auxiliary heat & fuel, diagnostics) Independent, with common, distributed time-base (fibre-optic + local decode) Controlled by specific Operators Connected by ethernet (TCP/UDP/IP; > 100 systems, miles of copper/fibre) Operations (experiments) Parameter sets designed by Session Leader in pulse schedule Distributed to the Systems by Level1 Supervisor infrastructure Checked and loaded to machine by Engineer-in-Charge, and System Operators Distributed real-time control Systems Real-time, calibrated outputs (avoid device dependence) Real-time data sent to/from a Central Controller over ATM AAL5 (~ 40 systems) Central Controller has its own Operator (PDO) Operations Control algorithm - conceptualised by Scientists, realised by PDO Event driven (step NB on n=2 mode) and feed-back (3He conc, q-profile) High level language in pulse schedule ICALEPCS 2005 / RTMC at JET / R.Felton

  6. Hierarchical Machine Control L1 Machine Supervisors user interface component data parameter data results data user & system logs L2 Machine Systems control & status start & stop set-up & readout r-t signal processing r-t physics L3 Device Drivers specific functions Level 1 Pulse Magnets Gas Heat Diagnostics Magnets Gas Heat Diagnostics parameters results Level 2 NB oct4 RF ... LIDAR ECE ... control status Level 3 psu gas valve laser recorder ... ICALEPCS 2005 / RTMC at JET / R.Felton

  7. Machine Operations The EIC and Operators validate the parameters (JET Operating Instructions) and load the plant. Other users (e.g. Heating, Diagnostics) set-up their equipment. The Plasma Duty Officer prepares and loads Real-Time Control Algorithms. Check & Load Pulse Schedule EIC, Operators Edit Pulse Schedule SL Pulse Schedule Pulse Schedule log JET plant state Run Pulse EIC Pulse Schedules reference to other pulse schedules or JET pulses convert physics parameters to control parameters. validate parameters for consistency and safety. non-experts use expert scenarios for otherwise tricky situations (shape) JET machine ICALEPCS 2005 / RTMC at JET / R.Felton

  8. The JET Real-Time Control Facility - Basic Shape & Current Control Magnetics PF Coils Interferom Density GAS + Pellets plasma NBI ICRH LHCD TAE Comms network analogue ICALEPCS 2005 / RTMC at JET / R.Felton

  9. The JET Real-Time Control Facility - 2005 Shape & Current Control (PPCC) PF Coils Magnetics VUV impurities GAS + Pellets Interferom/Polarim Vis Da, Brem, ELM NBI Neutron X-ray etc. Vis H/D/T plasma ICRH ECE Te (R) Confinement q profile LHCD CXS Ti (R) Flux surfaces EQX TAE / EFCC LIDAR Ne&Te(R) Wall Load MSE pitch (R) EQX kinetic map Simulink code Coil Protection X-ray Ti (0) Pale blue = Diagnostic, Sky blue = Analysis, Red = Heating / Fuelling / Magnets & Power, Yellow = PPCC (XSC), Green = RTMC R-T Controller R-T Signal Server Comms network ATM, some analogue ICALEPCS 2005 / RTMC at JET / R.Felton

  10. Data physics device independent standard data sets sizes : 4 to 400 float pt nos. rates : 1 to 250 ms Connections fast, low latency < 0.15 ms one-to-many changes : local impact isolation : fibre-optic range : 1 .. 100 m Technologies analogue messy ATM AAL5 configurable, reliable, available Industry standard, multi-platform, multi-vendor Time - a seperate network Distributed Process Control (Real-Time) Level 2 RTControl Magnetics NB Interferom LH q-profile ... ... ICALEPCS 2005 / RTMC at JET / R.Felton

  11. Diagnostics & Analysis Earl Ferrers:“My Lords, what kind of thermometer reads a temperature of 140 million degrees centigrade without melting?” Viscount Davidson:“My Lords, I should think a rather large one.” from a debate on JET in the House of Lords (1987) Wide range of processing techniques, and space / time resolution Filtering and down-samplingBlack Body Bolometer 48 chan, 2ms out Cross-calibration factorsElectron Cyclotron Emission 96 chan. 2ms Phase tracking of modulated signals Far InfraRed Interferometry 15 chan. 2ms Lock-in amplifiers (in software) Motional Stark Effect 25 chan. 2ms Levenberg Marquadt spectral fitting Charge Exchange Spectr. 14 spectra, 50ms Thomson Scattering LIDAR laser 250ms, analysis 25 ms Plasma magnetic boundary by Taylor expansion “XLOC” 65 coeffs, 2ms Finite element MHD equilibrium Grad-Shafranov “Equinox” 500 pt mesh 25ms Interpolation Te, Ne, q, etc on flux surfaces “Equinox map” r/a = 0; 0.1; 1.0 The JET LIDAR Thomson scattering system ICALEPCS 2005 / RTMC at JET / R.Felton

  12. Magnets, Heating & Fuelling Physics Inputs Outputs Rate Shape & Current Magnetics PF currents [9] 2 msVertical Stability Fast Radial Field 0.2 ms Gas & PelletsGIM[3] GIM[3] 10 msDensity Control Dens[3] Dens[3] 10 ms Neutral BeamPreq[8] Pact[8] 10 ms120kV 60A 20 MW Ion Cyclotron RFPreq[4], dFreq[4] Pact[4], dFact[4] 10 ms25..50 MHz 4MW Lower Hybrid RFPreq[3] Pact[3] 10 ms12 GHz 4MW Alfven EigenmodeFreq Fact 10 ms [n] refer to Groups == flexible selection of different NB PINIs, RF oscillators, antennae, gasses, etc. ICALEPCS 2005 / RTMC at JET / R.Felton

  13. The Real-Time Controller Preparation Level1 • User (PDO) designs and loads the algorithm • High level process block / data flow language Operation Level2 • RTCC receives measurement data • RTCC evaluates the user algorithm • RTCC sends heat /fuel requests Diag. Inputs Algorithm RTCCevaluator Features • flexible, general purpose (not low-level code) • easy (for PDO) : Event-triggered e.g. disruption avoidance, MHD Feedback SISO e.g. b with NBI • difficult (even for PDO) : MIMO control e.g. profiles Vector, matrix calculations, state-space Modular sub-routines Heat/FuelOutputs Real-time 10 ms cycle ICALEPCS 2005 / RTMC at JET / R.Felton

  14. The Real-Time Controller - Matlab/Simulink extension Preparation Matlab/Simulink & Level1 • User designs Matlab / Simulink models • User generates C function, data and DLL files • User transfers the code and parameter files to RTMX Operation Level2 • RTMX receives Diagnostic data, etc. • RTMX sends control requests to RTCC • RTCC relays the Heat/Fuel requests Diag. Inputs Simulink model RTMX processor RTCCevaluator Features • Flexible • EFDA users work on control problem at home lab • Use Matlab / Simulink function libraries (discrete time) • Responsibilities • PDO still loads and runs RTMX and RTCC • Protection stays with Local Managers Heat/FuelOutputs Real-time 10 ms cycle ICALEPCS 2005 / RTMC at JET / R.Felton

  15. Control Design E(z) error Ufb(z) feedback r(t) or R(z) reference C uff(t) or Uff(z) operating point P y(t) or Y(z)sensor u(t) or U(z) actuator System Identification To obtain signals Actuator : u(t) e.g. PNB and Sensor y(t) e.g. bNuse theoretical models TRANSP, JETTO, ASTRA, CRONOS, GS2, …or use experimental data. Model the process P as a differential equation for y(t) resulting from u(t). use State-Space or Laplace transforms : Y(z) = GP(z) . U(z) Control Design Design a controller C which achieves a desired reference signal r(t) by driving the actuator u(t) using feedback of the measured signal y(t) within constraints (e.g. error, settling time)Check the controller C by simulation, using the process model P U(z) = GC(z) . E(z) E(z) = R(z) - Y(z) ICALEPCS 2005 / RTMC at JET / R.Felton

  16. RT System Engineering • RT systems have been developed to satisfy JET Scientific Programme • they work in parallel with existing measurement and control systems • they integrate with existing system infrastructures • Even so, diversity and sustainability not always balanced • Common Application Frameworks - HTTP protocol • 1 VxWorks, 2 Windows - healthy competition - should have prize-giving ! • Common Platforms • VME + PowerPC + VxWorks & PCI + PC + Windows - future ? • Association-supplied Diagnostics “In-kind procurement” • Windows + Linux diverse interfaces, long-term support of internals ? • RT systems will evolve further • Need to improve functional partitioning, and data distribution • Model-based system engineering not yet established at JET way to go! Diagnostic Analysis Control Actuator Diagnostic Analysis Control Actuator ICALEPCS 2005 / RTMC at JET / R.Felton

  17. Work In Progress (JET’s EP programme) • Magnets / Shape and Current Control eXtreme Shape Control Plasma Ops, CREATE, ENEA, CEA Coil Protection System Power Supplies • Heating and Fuelling xxLM upgrade to PowerPC and ATM CODAS RF frequency control, LH position control CODAS • Diagnostics Bolometer, MSE, X-ray Expts, CODAS visible cameras, video distribution, hot spots Expts, CODAS • Analysis Matlab / Simulink Plasma Ops Equinox and Polarimetry, MSE Plasma Ops, CEA, U.Nice Disruption Prediction Plasma Ops, U.Naples, ENEA L-mode / H-mode Plasma Ops, & Murari • Databases & Communications extend ATM network, Plasma Ops, CODAS ICALEPCS 2005 / RTMC at JET / R.Felton

  18. Long term To Do (JET’s EP2 programme) • Magnets / Shape and Current Control • Vertical Stabilsation upgrade project ~ many Associations, ~ MEu ! • Error Field Correction Coils control ? • Heating and Fuelling • ELM info for ITER-like antenna ? • Pellet synch • Diagnostics & Analysis • EP2: Be / W Diagnostics, Neutron and Gamma Cameras • Alven Eigenmodes ? • RT magnetics analysis to speed up PostPulse Analysis • “Integrated” Analysisancient (map onto flux) and modern (pattern recog.) • Databases & Communications & Computers • try EPICS, MDSplus • evaluate new network technology Is there an Integrated Services Data Network (control, status, events, audio, video, time)? • evaluate new computer technology PCIexpress, CELL ICALEPCS 2005 / RTMC at JET / R.Felton

  19. Real-time Diagnostics simplified operation and analysis :: reliable quick-look real-time processing will be “designed in” to many new Diagnostics limited by lines of sight, field of view, calibration dependencies Real-time Magnets, Heating & Fuelling improving modelling and control algorithms for shape and stability improving power output and control Real-time Experiment Control SISO and MIMO demonstrated; more sophisticated tools needed Real-time Communications ATM ok - fast enough for most applications, flexible, reliable Science Requirements (JET programme in support of ITER) can best be satisified by Real-Time Measurement and Control Scientific Task Forces explore Plasma and Fusion Physics, and physics-based control concepts - either simple or complex Real-time systems are the means to practically demonstrate the concepts. Summary ICALEPCS 2005 / RTMC at JET / R.Felton

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