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Primary Ion Beams in the North Area: Design of the Safety Interlock Information for SPS-OP 14/2/2014. D.Manglunki presenting the work of T. Hakulinen, F. Havart , S.Hutchins , P. Ninin , P.Odier , S.Reignier , F. Valentini , D. Vaxelaire , & colleagues. Motivation.
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Primary Ion Beams in the North Area:Design of the Safety InterlockInformation for SPS-OP 14/2/2014 D.Manglunki presenting the work of T. Hakulinen, F. Havart, S.Hutchins, P. Ninin, P.Odier, S.Reignier, F. Valentini, D. Vaxelaire, & colleagues.
Motivation • Until recently, primary ion beams could be sent towards the North Area only during periods where no protons could be present in the SPS (ex: Pb ions at 13 & 80 GeV/u in December 2010, during PS proton injection septum fault). • For the forthcoming Ar, Xe, and Pb runs, it is foreseen to intermix both proton and ion cycles in the same super-cycle. • Although highly unprobable, it itnot impossible in these conditions to extract a high intensity primary proton beam to the North Area, exposing personnel to a radiation hazard: • Wrongly programmed injection of protons on an ion cycle • Accidental firing of the extraction elements during a high intensity proton cycle • Installation of a slow extraction proton cycle (SFTPRO) during primary ion operations • The principle of an interlock based on BCTs, preventing the extraction of a beam more intense than 2x1011 charges, has been proposed by the SPS OP team leader, and approved by the Beams Department Safety Officer in March 2009.
Technical Solution • Two BCTs installed in BA5, measure the beam intensity and give veto signal if I>2x1011 charges. • The interlock acts on the power supplies of extraction magnets MST and MSE in BA2, forcing them to quasi-zero current if the interlock gives a veto signal. • The interlock function is activated by an “Ion-mode” key in the CCC • Diversely redundant designat the level of measurement, control, transmission & action
Implementation • Respect norms IEC 61511 (process industry) and IEC 61513 (nuclear installations). • Two interlock chains: PLC and wired interlock(response time < 200 ms). • PLC chain based on SIEMENS S7 300 CPU and remote I/O with fiber optic cabling. • Wired chain based on HIMA Planar 4 modular wired logic. • See technical spec EDMS 1146023.
BCTs • Pure hardware solution for maximum reliability and availability • 2 new DCCTs, designed and made at CERN, installed in June 2012 in SPS point 5 • Identical and independent systems • Permanent monitoring of the circulating beam intensity (IB) • Comparator on the analogue signal • threshold @ 2x1011charges • Self-check system to assess the DCCTs performance • 2 status sent to the interlock system indicating • whether IBis > or < 2x1011 charges • whether the DCCTs are available or under test • Real-time software for remote monitoring
Self-check principle • Continuous check: • Performed in the DIAGNOSTIC UNIT • Assessment of important DCCT parameters: • Current consumption • Demodulation signal amplitude • etc. • Quick Check: • Performed automatically once per cycle before injection in the CHECK & COMPARATOR UNIT • Verification of the DCCT and comparator responses to a sequence of 6 calibrated current pulses injected into the monitor • Results stored until the next Quick Check • Validity period fixed to 60s One should tune the right balance between check severity and system availability
Status delivered to the Interlock System Each DCCT delivers 2 status and their complements to the 2 different inputs of the Interlock System (PLC and wired) Galvanic insulation by opto-couplers • LOW_IB_STATUS • TRUE IF Ib < 2x1011charges • AND Self-Check result is OK • AND NOT_IN_CHECK_STATUS is TRUE • NOT_IN_CHECK_STATUS • TRUE when the DCCT and the comparator are available, i.e not in quick check process
Acting on the REF-in of the converter to prevent extraction, forcing it to Imin Feedback to check I=Imin Check if system actually prevented an accident, in which case DSO action is required Actuator card between the Mugef and the Converter control crate -> direct control on the current reference MSE-MST power supplies
Normal behaviour: extraction of low intensity beam • The reference simply passes through the card (REF-OUT=REF-IN) as the NO_EXTRACT_VETO signal from the Interlock is high, allowing extraction. Status NO_REF_FAULT DCCT2 Ierreur - + Idcct I> Carte Ions/Protons Interlocks REF-OUT (Control crate) REF-IN (Mugef) I0 REF Imin REF Imin INTL-FAULT REF – IN < I0 NO_EXTRACT_VETO (PLC) Reset with Key AND NO_EXTRACT_VETO (Wired)
Normal behaviour: high intensity beam, no extraction The BCTs detect an intensity I>2x1011 charges: One of the NO_EXTRACT_VETO signal from the interlocks (PLC and Wired) is low The reference is forced to Imin=(720A for MSE ; Imin=225A for MST), minimum current reference given by the CCC, inhibiting the pulse converter. Status NO_REF_FAULT DCCT2 Ierreur - - + + Idcct I> Carte Ions/Protons Interlocks REF-OUT (Control crate) REF-IN (Mugef) I0 REF Imin REF Imin INTL-FAULT REF – IN < I0 NO_EXTRACT_VETO (PLC) Reset with Key AND/OR NO_EXTRACT_VETO (Wired)
Abnormal behaviour • First Case: The signals NO_EXTRACT_VETO are low. The current reference REF-OUT is forced to Imin. • In the second step, a reference REF-IN (above I0) is still received. • This abnormal case should be analysed: A signal INTL-FAULT is generated and the converter is stopped. • Second Case: The converter of a pulse cycle is allowed, the REF-IN is greater than I0. • In the second step, the signals NO_EXTRACT_VETO become low: This abnormal case should be analysed. The associated actions are: • The reference REF-OUT is forced to Imin. • A signal INTL-FAULT is generated and the converter is stopped. • If either of these cases occurs, a fault in the converter will be activated, which can only be reset with a key. This key will be available to authorized persons competent to reset this fault (DSO), after an analysis of the fault event.
Abnormal behaviour First Case: The signals NO_EXTRACT_VETO are low. The current reference REF-OUT is forced to Imin. In the second step, a reference REF-IN (above I0) is still received. This abnormal case should be analysed: A signal INTL-FAULT is generated and the converter is stopped. Second Case: The converter of a pulse cycle is allowed, the REF-IN is greater than I0. In the second step, the signals NO_EXTRACT_VETO become low: This abnormal case should be analysed. The associated actions are: The reference REF-OUT is forced to Imin. A signal INTL-FAULT is generated and the converter is stopped. If either of these cases occurs, a fault in the converter will be activated, which can only be reset with a key. This key will be available to authorized persons competent to reset this fault (DSO), after an analysis of the fault event. Status NO_REF_FAULT DCCT2 Ierreur - - + + Idcct I> Carte Ions/Protons Interlocks REF-OUT (Control crate) REF-IN (Mugef) I0 REF Imin REF Imin INTL-FAULT REF – IN > I0 NO_EXTRACT_VETO (PLC) Reset with Key FAULT AND/OR NO_EXTRACT_VETO (Wired)
Status as of today (February 2014) • 2 BCTs installed in BA5 and tested with beam • Design of power supply safety system done; implementation being done TE/EPC • Interlock design done and internally tested. • Interface to BCTs tested. • NOW: approbation of the Technical Spec. • Final version of the BCT/Comparator electronics • MST/MSE power supply interlocking electronics • Installation of one Fast BCT (additional beam monitoring) • Global BCT/Comparator system commissioning without beam • Interface to MSE/MST final testing. • Inter-site cabling: • BA5, CCC, CCR done. BA2 planned for March. • All Fiber-optics cabling finished • Integration tests with all components will be connected early 2014. • Finalization of installation and test documentation. • DSO-tests to be scheduled before SPS start-up.
Typical SPS Super-cycle North Area Ion cycle with slow extraction HiRadMat proton cycle LHC proton cycle
Interlock Schematic System monitoring interface using TIM
SIF 1: Avoid high intensity proton beam extraction to north area in ION mode TRIGGERING EVENT- DCCT 1 CHECK WATCHDOG INVALIDATION: TRIGGERING EVENT- SAFETY VETO REMOVAL FROM MST/MSE TRIGGERING EVENT- DCCT 2 CHECK WATCHDOG INVALIDATION:
SIF 2: Send and maintain veto to BIS in case of MSE/MST malfunction TRIGGERING EVENT- SPS SAFETY BEAM DUMP REQUEST:
General layout In red: Minimum system required to fulfil the initial specification In green: Monitoring, remote diagnostic tools + acquisition + logging
Time diagram 4 Cases Range 3 Extraction Permitted NO Extraction NO Extraction NO Extraction Will be NOT_IN_CHECK_STATUS in the final version
Acquisition, monitoring and logging • Acquisition via a RT program running in the FEC (Front End Computer) • 1 FEC per DCCT • ADC • 16 signals per system (Beam intensity on 4 ranges, system 1 and 2, status, etc.) • Sampling rate: 100 S/s • Start 900ms before injection • Stop ~20ms after ejection • Reading after ejection • Input Register • 17 status per DCCT (result of every elementary check, etc.) • Reading after ejection • Data publication via a FESA class once per cycle after ejection • Logging • Timber system • To be decided: • Which signal (Beam intensity, LOW_IB_STATUS, NOT_IN_CHECK_STATUS?) • What time resolution?
Test with beam (SPS.LHC4; 12.10.2012) Real signals seen via the FESA Navigator ADC bin Will be NOT_IN_CHECK_STATUS in the final version Time [ms]
BCT Planning • March 2009 Specification draft • April 2010 ECR 1075945 v1 • Jan 2011 Cable pulling for provisional location (BB5) • May 2011 Writing the technicalspecification (v1) • June2012 ECR 1075945 v2 • Sept 2011-May 2012 Manufacturing of mechanics • March - June2012 Building the electronic prototypes • June 2012 Installation of 2 monitors in point 5 • Since August 2012 Test of DCCT & Soft RT programme • Jan-Feb 2013Tests with the Interlock system • LS1-Cable pulling for final location (BA5) -Approbation of the technical specification -Make final version of the electronic -Installation of one Fast BCT (additional beam monitoring) -Global System Commissioning without beam • After LS1 -Global System Commissioning with Beam -Operation with Ions Beam in North Hall Now Required for the next step
Actuator card between the Mugef and the Converter control crate -> direct control on the current reference • However, setting the current reference to Imindoes not guarantee that in the case of a malfunction of the electronic control of this converter, the current in the circuit is actually Imin • Supplementary DCCT measures the converter output current • compared to the input reference current “REF-IN”, giving us an error signal “Ierror”. • If difference too large, comparator drives a relay into fault (open) position and cause action on the beam(signal NO_REF_FAULT). • DCCT status managed by “Ion/Proton actuator card”: • DCCT dry status contact connected in series with relay contact -> any problem with the DCCT will also cause appropriate action on the beam (signal NO_REF_FAULT). Idcct DCCT2 Crate Status Mugef INTL-FAULT REF-IN Crate Ions/protons Interlocks NO_EXTRACT_VETO (PLC) NO_EXTRACT_VETO (Wired) REF-OUT RESET with KEY NO_REF_FAULT Converter control crate