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The Control System for the LHC tunnel cryogenics Controlling C ool A ccelerators Controle da Criogenia de Aceleradores de Partículas. Dr. Paulo Gomes on behalf of the team CERN – TE – CRG with the precious contributions of the colleagues: Project Associates (NTU-Athens, AGH-Krakow)
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The Control System for the LHC tunnel cryogenicsControlling Cool AcceleratorsControle da Criogenia de Aceleradores de Partículas Dr. Paulo Gomes on behalf of the team CERN – TE – CRG with the precious contributions of the colleagues: Project Associates (NTU-Athens, AGH-Krakow) Industrial Support Cryogenic Operation AB – CO
LHC : 27km proton-proton collider , 8 sectors of 3.3 km Sector = 3.3 km 2 460 m 270 m 270 m 170 m 170 m
energy per beam: 7 TeV luminosity: 1034 cm-2s-1 main dipoles field: 8 T current: 12 kA main magnets superconducting: 1200 D + 400 Q
QRL feeds He to the superconducting magnets in all magnets +QRL: 10 000 cryogenic sensors & actuators super-fluid liquid He bath temperature: 1.9 K cryo distribution line feeding magnets every: 107 m
5 000instruments 52 DFBs support and cool Current Leads that power the magnets
RF superconducting accelerator cavities @ 4.5 K 16 cavities grouped on 4 modules, on IP4 200cryo instruments
CERN Control Centre architecture CRYO-SCADA PVSS data server CIET PVSS data server surface - local control room Ethernet Technical Network 2 PLC Siemens S7-400 500 ms cycle 8 FEC WorldFIP – Ethernet Gateway 500 ms cycle 4x Profibus 1.5 Mbit/s 4x WorldFIP 1 Mbit/s 100 m 100 m alcoves - radiation free FieldBuses ← large distances industrial electronics → protected areas CVs → electronics moved into protected areas front-end electronics → radTol custom made “intelligent” CV positioners with electronics point-to-point cables tunnel - radiation 180 cryogenic CV without electronics 100 FIP crates custom rad-tol electronics sector = 3.3 km
a few numbers (per sector) 2 000 sensors and actuators 100 FIP crates 2 Siemens S7-400 PLCs 500 Closed Control Loops 1 100 alarms & interlocks PLC cycle 500 ms 5 600 objects of 16 types 250 000 lines of SCL source code >3 Mbytes of machine code AND... the last 5 sectors were to be deployed at a rate of 1 new sector every 2 weeks
Databases are intensively used - LHC Controls Layout DB 17 055 instrumentation channels 798 FIP crates 855 cards 1 738 Profibus components 5 000 cable numbers LHC Layout Database XML files for Mobile Test Bench cabling files for connecting & inspecting cables specification files for manufacturing FIP Crates specifications for control software PLC , FEC, SCADA
software production cycle Layout DBs Layout DBs Layout DBs Specs *.xls Specs *.xls Specs xls Proces Logic *.xls Proces Logic *.xls Process Logic Checker Code generation Code generation Compilation 1d 1h 2d 0.5d Test (existing)UNICOS framework (Unified Industrial Control System) provides methodology & baseline tools to program industrial control systems @ CERN (developed)generator of process specifications extracts from DBs the list of all objects, parameters, logical relations (written) logic templates similar code for objects of same family (existing)UNICOS source code generator for PLC & SCADA code compilation with UNICOS libraries project deployment on field machines (new) last 5 LHC sectors to be deployed at a rate of 1 new sector every 2 weeks (new) checker of specifications (new) external function with common logic (new) generator for specificities not covered by UNICOSgen (new) run/check code on test PLC with simulated inputs full sector code generation now takes 2 days Templates Template Template Templates Deployment
SCADA : Supervisory Control & Data Acquisition CIET for Instrumentation Experts 200 panels / sector 40 synoptics, 35 bar-graphs, 60 alarms & interlocks Repetitive panels use parameterized templates Parameters generator, directly from DB CRYO-SCADA for operation
The control software production relies strongly on a set of databases and on a package of automatic generation tools, which have been developed to create code in several steps, according to a well established methodology The UNICOS automated generation & checking tools proved to be essential for flexible and robust PLC code generation Thanks to extensive automatic code generation, we achieved reduced software-production time and effort increased code reliability minimised risk of human mistakes simplified long term maintenance We managed to reach a deployment rate of 1 new sector every 2 weeks, while in parallel giving support and modifications on other operating sectors And… Conclusions
10 Sep 08 – the first proton beams in the LHC At 10:28, one beam of protons was steered around the machine for the 1st time Around 15:00 the other beam circulated in the second ring (anticlockwise) (http://cdsweb.cern.ch/journal/article?issue=39/2008&name=CERNBulletin&category=News%20Articles&number=1&ln=en)
The 19 Sep 08 incident In Sector 3-4, during powering tests (without beam) at high current (9 KA) for 5 TeV a fault occurred in one electrical connection between magnets, resulting in mechanical damage and release of helium from the magnets into the tunnel. During the ramping-up of current, a resistive zone developed in the faulty connection An electrical arc punctured the L He enclosure, leading to a release/expansion of He into the insulation vacuum of the cryostats; the pressure-relief system was not able to contain the rise of the He pressure; large pressure forces displaced some magnets; several magnets were contaminated with dust; and had their multilayer insulation blankets damaged; (http://press.web.cern.ch/press/PressReleases/Releases2008/PR14.08E.html)
Why did the LHC break down http://cdsweb.cern.ch/record/1176912 .flv
The measures taken Sector 3-4 was warmed and 53 magnets were taken to the surface for repair or cleaning New systems were installed, to ensure that similar incidents will not happen again: enhanced protection system, with more sensitive measurement of resistance (early detection of high-resistance, and quench, of electrical connections) new pressure relief system, with installation of extra relief valves (avoid high pressure to build inside the magnets) the anchoring of the LHC magnets to the floor was strengthened In all LHC sectors, 10 000 high-current superconducting electrical connections were tested: the ones with critically high resistance were repaired the remaining ones do not pose problem for safely running below 5 TeV (http://press.web.cern.ch/press/PressReleases/Releases2009/PR02.09E.html, PR06.09E.html, PR13.09E.html)
The re-start plan After finishing cooling and electrical-tests on all sectors, the LHC beams will restart in Nov09; During a few weeks: Inject and capture proton beams in each direction, for a few days, take data for collisions at the injection energy (0.5 TeV), gradually increase energy up to 3.5 TeV per beam (= 1/2 nominal E); Run at 3.5 TeV to collect data and gain experience then, increase energy towards 5 TeV per beam; At the end of 2010: run with lead ions After that: shut down and do the necessary to have 7 TeV per beam in 2011 (http://press.web.cern.ch/press/PressReleases/Releases2009/PR13.09E.html)
10 Sep 08 - first beams @ CERN – media event http://www.youtube.com/watch?v=fxJqVsQ6yjc .flv