Ieiri, M

Kato, Y

Kusano, E

Minakawa, M

Noumi, H

Suzuki, Y

Takasaki, M

Tanaka, K H

Yamanoi, Y

CERN Document Server

THE NEUTRINO BEAM LINE CONTROL SYSTEMY. Suzuki, Y. Yamanoi, E. Kusano, M. Ieiri, Y. Kato, M. MinakawaH. Noumi, K. H. Tanaka, M. TakasakiInstitute of Particle and Nuclear Studies, KEKTsukuba, Ibaraki, JapanAbstractThe control system of the beam line for the long-baselineneutrino-oscillation experiment at KEK is reported. Thefast-extracted beam from the KEK 12-GeV protonsynchrotron (KEK PS) is transferred through a 400m longbeam line which consists of 104 magnet power supplies,including a 2.5MW magnet power supply and two 250kApulse power supplies for magnetic horns. The controlsystem for these magnet power supplies is PC-based, anduses LAN, GP-IB, POD (programmable operation displaywith touch panel). The lower level device controllers aredesigned to reduce the load of the system-controller PC.When the device controller receives a message to set theoutput current, it performs: sequential check interlock, setpolarity, turn on main transformer, then set a smoothoutput current, and watch the condition. For the 250kApulse power supply, the controller performs not only theordinary function of the magnet power supply, but alsotiming control of the high-voltage capacitor charging unitand the triggering unit to synchronize with the KEK PS.The condition of the magnet power supplies is available tomonitor through the Web browser. The run startedJanuary 1999. The initial problems or fixed are alsoreported.1  INTRODUCTIONFigure 1 shows the neutrino beam line. The north counterhall is a physics experimental area. There is a primarybeam line, EP1, which transfers the proton beam to theneutrino beam line and a parasitic beam line, EP1-B, andtwo secondary beam lines, K5 and K6. The neutrino beamline is 250m long, and transfers protons to a targetembedded in the 250kA pulse current magnetic horn(horn-1). Horn-1 and a following horn (horn-2) focus thepion particles produced by the target, and transfer them tothe next section decay volume tunnel.Table 1 gives the number of magnets and power suppliesequipped in the north experimental area. Table 2 listsspecial power supplies for the neutrino beam line.  Thosepower supplies are installed in three sites: the north hall,power station 1, and power station 2. Each site is far fromthe control room of the north hall. It then decreases theefficiency of the check-up and maintenance work of thepower supplies, the magnets, and the control system.Figure 1: 12GeV-PS, North counter hall, and neutrinobeam lineLine Magnet PowersupplyLocationEP1 29 29 North hallEP1-B 13 14 North hallNeutrino 1 34 23 Power station-1Neutrino 2 49 40 Power station-2Table 1: Equipped magnets and power suppliesArc section 17 magnets 2.5MW DC 1 set17 collection coils 90A, 40V dc /GPIB 17Horn 1 / Horn 2 250kA 2msec,half-sin 2Table 2: Special power suppliesInternational Conference on Accelerator and Large Experimental Physics Control Systems104International Conference  Accel rator and L rge Experim ntal Physics Control Systems, 1999, Trieste, ItalyTherefore, the control system must provide not only anoperation interface for the operator, but also effectivesupport to the check-up and maintenance work on bothperiods of the construction and the following usual run.Then, to control the neutrino beam line, two types ofpower supply controllers were developed. One (PSCx8)was for eight magnet power supplies of the ordinal type.The other (HMPSC) was for the pulse power supply of the250kA magnetic horn. The features of the controllers aregiven below:1. The operation and check procedures of themagnet power supply are programmed in thosecontrollers (PSCx8 and HMPSC).2. It reduces the load of the system (beam line)controller PC.3. The HMPSC not only has the ordinary controlfunction for power supplies, but also timingcontrol to synchronize with the fast-extractionbeam.4. Those controllers could easily control the powersupplies by PC and an interpretive language (e.g.BASIC or visual language HP-VEE). It waseffective in the construction stage of the neutrinobeam line. It saved time and labor of the check-up work and test operation of the equipment,magnets and power supplies at the local sites.2  SYSTEM CONFIGURATIONFigure 2 shows the configuration of the control system.Table 3 shows the equipped devices and those for storage.In consideration of less maintenance work, those devicesare selected. The magnet power supplies are installed atthree sites. At each site, the magnet power supplies aredivided into groups of eight. The eight magnet powersupplies are connected to one PSCx8 with shortstandardized cables. Those PSCx8s and a Windows PCsystem controller are connected through GP-IB extendersand coaxial cables At the initial design of this part, theconnection between the PC and PSCx8s was expected touse LAN, and had been tested. But at the final stage of theconstruction, it was changed to a direct connectionthrough coaxial cables to increase the reliability.PC System controller Windows NT/Hard discPOD Human interface Flash memoryPSCx8 Eight Power supplies controller ROM-baseHMPSC Horn Power supply controller ROM-baseTCS-7146 LAN/RS-232C converter Flash memoryHP-E2050 GP-IB extender Hard logicTable 3: Devises and their storageFor operation, POD (programmable operationdisplay) was introduced into this control system. The mainpurpose of the manufactured POD was to be used withPLC (programmable logic controller) in a production line.The POD has a colored display; touch switches on thedisplay, and a serial interface (RS 232c). Four PODs areequipped. One in the control room is directly connected tothe PC. Others are connected with RS 232c/LANconverters.Figure 2: Configuration of control systemFigure 3: a Web page shows current stabilityThe POD offers sixteen programmed screens tooperate and monitor the power supplies. Loading todisplay the screens and to treat data input is performed bythe POD, itself. Then, loading of the PC becomes less105than that using a terminal. The PC’s program of thecontrol system including Web pages was developed by avisual programming language (HP-VEE). Thedevelopment time was comparatively short in spite ofincluding effective human interface. The PC periodicallymonitors the status of the magnets and power supplies.The result of the monitoring is used to make Web pages.Figure 3 shows a Web page used to monitor the currentstability of the magnets.3  POWER  SUPPLY CONTROLLERThe PSCx8 is a controller for eight power supplies. It actsas a good tool, and reduces the time and labor for thetesting operation of the power supplies. Likewise, itreduces the load of the beam-line controller PC. ThePSCx8 consists of cards installed in a STD-BUS (IEEE-961) card rack. Table 4 gives a list of the circuit boards.Table 5 gives a list of the steps performed by the PSCx8when the data of the output currents of the eight power-supplies are received.Board Function CharacterCPU Z-80 4MHz, ROM-baseGP-IB TMS-9914DAC 16-bit    x8 0 t0 10V, 1mV-resolution16ch-MPXADC AD1170Output current and voltagemonitoringIN 24-bit x3 Read statusOUT 24-bit x1 Actuate on/off, polarity, reset-interlockDIP-SW 8 bytes Power supply ratingTable 4: Circuit boards for PSCx81 Check status (Local/Remote) and interlocks2 Set polarity switch3 Reset interlock circuit and check status4 Main transformer turn ON5 Check turn ON status6 Current set ramp-up and status-check loop7 Report the result by SRQ8 Current monitor and status watch loop--- SRQ9 Continue --- receive current 0 data10 Current down to 0 and status-check loop11 Turn OFF, check status12 Report the result by SRQ13 Stand-by (monitor loop of status, output current,and voltage) Table 5: Control Sequence of magnet power supply4  HORN POWER SUPPLY CONTROLLERThe HMPSC is a controller for one horn-magnet powersupply. This controller is also designed [1] based on thesame policy as the PSCx8. Also, the hardwareconfiguration is almost the same. The timing controls ofthe high-voltage capacitor charging unit and the trigger ofthe output pulse are different. This part is performedeffectively by a combination of the Z80 interrupt function,Z80-CTC (counter timer circuit chip), and someadditional circuits. Table 6 gives a list of the circuitboards. Table 7 shows action of the HMPSC receivestrigger signals from the accelerator.Board Function CharacterDAC DAC701 Reference voltageDAC-2 AD7546 Modulate reference voltage toramp wave formIsolation Timing signal, interruptTable 6: Unique circuit boards for HMPSTrigger ActionA Charger ON/OFF.Generate Reference voltageB Delay timing control.  250kA pulseTable 7: Trigger signals5  CONCLUSIONBased on the initial design [2] of this control system, aUNIX workstation and x-terminals were expected to beused. Later, however, those devices were changed toWindows PC and PODs. The choice greatly reduced thetime to develop the human-interface program.   During thefinal-stage one-week work on this control systemconstruction, the time was short and tight, the PSCx8s andHMPSCs effectively supported engineers to check-up andtest the magnets and the power supplies. Aftercompletion, it has provided a good operator interface andWeb pages. The low-level controllers (PSCx8s andHMPSCs) and the human interface PODs reduce the loadof the system controller PC, and contribute to therealization of this economical control system; that is tosay, the functions are properly distributed.6  REFERENCES[1] Y. Suzuki et al., ‘Control and Timing of the 250kA pulsedMagnetic Horn’, ICALEPCS’97, Beijing, China, November3-7,1997[2] Y. Suzuki et al., ‘An interface for the neutrino beam linecontrol system’, IWCSMSA96, KEK, Tsukuba, Japan,November 11-15, 1996106

The Neutrino Beam Line Control System

The Neutrino Beam Line Control System

Abstract

Similar works

Full text

Available Versions

CERN Document Server