Real Time Measurement and Control at JET Overview & Status
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Transcript of Real Time Measurement and Control at JET Overview & Status
October 2005 ICALEPCS 2005 / RTMC at JET / R.Felton 1
Real Time Measurement and Control at JETOverview & Status
Robert Felton1, and JET EFDA Contributors1 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
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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
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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
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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
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Tokamak Measurement & Control
Hierarchical machine controlSystems (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 controlSystems
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)
OperationsControl 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
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Hierarchical Machine Control
L1 Machine Supervisorsuser interface
component data
parameter data
results data
user & system logs
L2 Machine Systemscontrol & status
start & stop
set-up & readout
r-t signal processing
r-t physics
L3 Device Driversspecific functions
Pulse
RF
laser
Magnets Heat Diagnostics
NB oct4 ECELIDAR ...
recorder ...
Level 1
Gas
parameters resultsLevel 2
Level 3
gas valve
control status
Heat DiagnosticsGasMagnets
...
psu
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Machine Operations
Pulse Schedule
Edit
Pulse Schedule
SL
Run Pulse
EIC
Check & Load
Pulse Schedule
EIC, Operators
Pulse Schedule
log
JET
machine
JET
plant state
Pulse Schedulesreference to other pulse schedules or JET
pulsesconvert physics parameters to control
parameters. validate parameters for consistency and
safety.non-experts use expert scenarios for
otherwise tricky situations (shape)
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.
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The JET Real-Time Control Facility - Basic
Magnetics
plasma
Shape & Current Control
NBI
ICRH
LHCD
GAS + Pellets
PF Coils
Comms network analogue
TAE
Interferom Density
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The JET Real-Time Control Facility - 2005
Magnetics
R-T Signal Server
R-T Controller
plasma
CXS Ti (R)
MSE pitch (R)
Flux surfaces EQX
Confinement
VUV impurities
Shape & Current Control (PPCC)
ECE Te (R)
q profile
Neutron X-ray etc.
Interferom/Polarim
NBI
ICRH
LHCD
GAS + Pellets
PF Coils
Vis H/D/T
Vis Da, Brem, ELM
Comms network ATM, some analogue
X-ray Ti (0)
LIDAR Ne&Te(R)
Simulink codeEQX kinetic map
Pale blue = Diagnostic, Sky blue = Analysis, Red = Heating / Fuelling / Magnets & Power, Yellow = PPCC (XSC), Green = RTMC
TAE / EFCC
Wall Load
Coil Protection
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Distributed Process Control (Real-Time)• 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
NB
RTControlMagnetics
...
Level 2
Interferom
LH
...
q-profile
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Diagnostics & Analysis
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 fittingCharge 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
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)
The JET LIDAR
Thomson scattering
system
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Magnets, Heating & Fuelling
Physics Inputs Outputs Rate
Ion Cyclotron RF Preq[4], Freq[4] Pact[4], Fact[4] 10 ms25..50 MHz 4MW
Lower Hybrid RF Preq[3] Pact[3] 10 ms12 GHz 4MW
Neutral Beam Preq[8] Pact[8] 10 ms120kV 60A 20 MW
Alfven Eigenmode Freq Fact 10 ms
Gas & Pellets GIM[3] GIM[3] 10 msDensity Control Dens[3] Dens[3] 10 ms
[n] refer to Groups == flexible selection of different NB PINIs, RF oscillators, antennae, gasses, etc.
Shape & Current Magnetics PF currents [9] 2 msVertical Stability Fast Radial Field 0.2 ms
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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 Algorithm RTCC
evaluator
Diag. Inputs
Heat/FuelOutputs
Real-time
10 ms cycle
Features
• flexible, general purpose (not low-level code)
• easy (for PDO) :Event-triggered e.g. disruption avoidance, MHD
Feedback SISO e.g. with NBI
• difficult (even for PDO) :MIMO control e.g. profiles
Vector, matrix calculations, state-space
Modular sub-routines
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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
Simulink model
RTCCevaluator
Diag. Inputs
Heat/FuelOutputs
RTMX processor
Real-time
10 ms cycle
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
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Control Design
System Identification
To obtain signals Actuator : u(t) e.g. PNB and Sensor y(t) e.g. N use 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)
C
P
r(t) or R(z)
reference
E(z)
error
Ufb(z)
feedback
y(t) or Y(z)sensor
u(t) or U(z) actuator
uff(t) or Uff(z)
operating point
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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 ActuatorDiagnostic Analysis Control Actuator
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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 FuellingxxLM upgrade to PowerPC and ATM CODAS
RF frequency control, LH position control CODAS
• DiagnosticsBolometer, MSE, X-ray Expts, CODAS
visible cameras, video distribution, hot spots Expts, CODAS
• AnalysisMatlab / 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
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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” Analysis ancient (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
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Summary• 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.