Van Zeijts, Johannes

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CDEV GENERIC SERVERS FOR RHIC COMMISSIONING ANDOPERATIONS Johannes van Zeijts, BNL, Upton, NY 11733, USAAbstractSeveral systems at RHIC are build using the CDEV Gener-ic Server environment. These include the on-line model-ing server (ACME), the system for managing ramps andreal-time control knobs (Ramp Manager), the longitudinalprofile monitoring and reconstruction system (Wall CurrentMonitor Manager), the beam position server (Orbit Man-ager), and several others. We describe these servers, theiroperational impact, and present results from the commis-sioning run.1 INTRODUCTIONThe Relativistic Heavy Ion Collider (RHIC) at BrookhavenNational Laboratory consists of two intersecting storagerings. Using super-conducting magnets, RHIC will be ableto collide ions from protons to gold. The existing AGS ac-celerator complex will be used as injector, supplying goldions at 10.8 GeV/u and protons at 28.1 GeV. The beams arethen accelerated in RHIC to 108 GeV/u and 249 GeV re-spectively. All ion beams except protons will cross the tran-sition energy during acceleration. At storage energy, thebeta functions in the interaction points are reduced from 10meters to 1 meter. The machine was declared operationalin August 1999 when gold beam was stored and acceler-ated in the Blue ring. Gold beam also was stored in theYellow ring for 1000 turns. Commissioning will resume inDecember, with collisions planned soon thereafter.The control system for RHIC is RPC based and de-scribed in [1, 2], while the control system for the AGS andBooster is of the ‘mature’ (i.e. older) type [3]. For this rea-son CDEV [4] was introduced to provide a common APIto both systems. Several generic applications, like data-logging, are written by the Control Group using the CDEVAPI. In addition, accelerator physics applications are au-thored by people in the Rhic Accelerator Physics group(RAP). There the CDEV API is used to provide access tothe control system and also to connect to the multiple ‘mid-dleware’ servers which are described in this paper.2 RHIC APPLICATION ENVIRONMENTThe Accelerator Physics applications used for RHIC com-missioning are build using the 3-tier control system view.Middleware servers perform data collation from Front-EndComputers (FEC’s), and timing synchronization. Otherservers provide a high level device view of the machineWork performed under the auspices of the US Department of Energy.(i.e. by ring name), or provide an interface to the ramping,magnet, and modeling systems.2.1 Magnet Control and RampingThe super-conducting magnets are powered by multiplepower-supplies in a main bus, multiple trim bus schemeshown in Figure 1. This was done to minimize the numberof power feed-throughs into the cold regions but it compli-cates the programming of the Wave Form Generator driver-s. Each WFG (Figure 2) needs to be programmed with awaveform which describes the change in magnet parame-ter like K, for quadrupoles, or angle, for dipole correctors.We define discrete points on this curve as ‘stepstones’, eachdescribing a full set of magnet settings. These stepstonesare presented as devices in the Ramp-Manager. Clients in-clude the Ramp-Editor where tunes and chromaticities canbe changed (Figure 3).A ‘ramp’ device contains a set of stepstones and as-sociated energies. Multiple ramp and stepstone devicesare available simultaneously in the Ramp-Manager. Eachof these devices supports the standard ‘get’, ‘set’, ‘moni-torOn’, and ‘monitorOff’ verbs for several properties. Inaddition a ramp device supports an ‘activate’ messagewhich will initiate the loading of the WFG’s.Q1Q2Q4Q5Q6 Q7Q1 Q2Q3 Q3 Q4 Q5 Q6150-150150-150150-150150-150150-150150-150AQ9QFA150-150150-150150-150150-150150-150150-150150-150150-15045006000Q7AA AAADEQ8QFAQ8 Q9QDAQDAA AC450-450BQT6B B B B BQT6QT5 QT4 QT4 QT5IF IFID IDFigure 1: Wiring of Power Supplies and Magnets2.2 Model ServersEach stepstone device provides access to the associatedoptics through properties like ‘LatticeFunctions’, ‘Orbit’,or ‘ClosedOrbitMatrix’, amongst others. In addition, tosupport what-if scenarios, we provide the logical devicesInternational Conference on Accelerator and Large Experimental Physics Control Systems480International Conference  Accel rator and L rge Experim ntal Physics Control Systems, 1999, Trieste, ItalyWFG WFGWFG WFG WFG WFGPS PSγΤPSRF RFVolt PhaseKnob Knob SequencerWFGManagerWFGKnobP B ρManagerRTDLEvent Link...Figure 2: Control Model of Magnets and Power-SuppliesFigure 3: StepStone Parameter Editing Window‘Blue’, and ‘Yellow’ for the two rings representing period-ic optics, and ‘BlueInj’, ‘YellowInj’ devices representingthe injection lines and the one-turn optics.The Accelerator Computational Model Engine (ACME)environment (Figure 4) is described in [8], and multipleservers are available in the same CDEV server domain.2.3 Orbit Display and CorrectionThe orbit system is monitoring approximately 700 BeamPosition Monitor (BPM) devices times 10 properties perdevice, on several tens of FEC’s. On receiving call-backsthe data is synchronized across the machine and a callbackis generated for each plane property (‘xtbt’, ‘ytbt’, ‘xavg’,and ‘yavg’) of the Blue and Yellow ring devices. The da-ta associated with the call-back has the position for 128up to 1024 turns for each BPM in the ring, the status foreach turn, and the associated timestamp in seconds and rev-olution count when the triggering event was issued. Theintegration with the Ramp-Manager is shown in Figure 5,CME AdapterCDEV Model Serverread/writeControl SystemLive Magnet Strengthslattice/strengthstransactionsCMELattice RepositoryOptics / Survey DatabasesModel DataCME Lattice AdaptersClient ApplicationsCDEVFigure 4: Model Server Program Processeswhere the Orbit-Correction application is shown retrievingdata from both the Ramp-Manager and the Orbit-Manager.Database AccessSystem ServicesApplication Architecture for the RHIC Orbit SystemFront-End VME Computers (FECs)Console Level Computers (CLCs)TuneMeasurementAdoIf TransactionsControls NetworkingBPMADOsBPM/DSPHardwareBPM/DSPHardwareLogging and AlarmsName ServerRamp ManagerEventMonHardwareEventMonADOsBPMADOsADOsWFGWFGHardwareOrbit ManagerOrbit Displayand CorrectionLinksRHIC Event Beam SyncsReal-Time DataCDEV CLIPFigure 5: Orbit Display and Correction Program Processes2.4 Wall Current Monitor ManagerThis manager asynchronously collects data from sever-al Wall Current Monitor (WCM) parameters and collatesthem into one cdevData which is delivered to interestedclients. Each set of profiles typically consists of 1000points times 100 turns. The manager also keeps a 15minute buffer of profiles for quick historic diagnostics. Theclients to this manager include an application which shows481a waterfall-like display of the profiles, and an applicationwhich uses a commercial widget to show an interactive 3Ddisplay of the profiles vs. turn. Both applications can up-date a live signal at 1Hz. It is planned that the tomographicreconstruction work done at CERN [11] will be integrat-ed through a server and accessed by new properties of thesame device names.2.5 SequencingThis application orchestrates the actions in the whole ma-chine. A minimal scenario involves injecting beam in theBlue ring, followed by a polarity change in the switchingmagnet, injecting beam in the Yellow ring, and the initial-ization and triggering of the synchronized ramping. Cur-rently this application is implemented in Tcl/Tk with a bi-nary extension to access CDEV. The sequence proceedsasynchronously where for micro-second resolution, delay-generators are preprogrammed and triggered by events onone of the RHIC event links. Events on these links aremonitored, on a slower time scale, by the sequencer andsubsequently acted upon.2.6 Gateway ServersControl system signals need to be available outside thelocal control network for use by interested 3’rd parties.These include users in the experimental halls and diagnos-tics users in their offices. For these purposes a CDEV Gate-way is installed which allows CDEV applications outsidethe firewall read access to a selected group of signals.3 CONCLUSIONSCDEV middleware servers have been deployed to great ad-vantage in the AGS/RHIC environment during the commis-sioning phase of RHIC. New logical devices add function-ality and flexibility to client applications, while hiding a lotof the complexities otherwise exposed to the end-user. TheCDEV Generic Server framework provides a robust and s-traightforward integration of Accelerator Physics serviceswith control system access, using the same CDEV API.4 REFERENCES[1] T. Clifford, D. Barton and B. Oerter. “The RHIC ControlSystem”, Proceedings of ICALEPCS’97.[2] L. Hoff, “Object oriented APIs for accelerator control sys-tems”, Proceedings of PAC’97.[3] J. Morris, J. Skelly. “Design, Evolution and Impact of theAGS/RHIC Control System”, these proceedings.[4] J. Chen, G. Heyes, W. Akers, D. Wu and W. Watson, “CDE-V: An Object-Oriented Class Library for Developing DeviceControl Applications”, Proceedings of ICALEPCS’95.[5] P. Cameron, R. Lee, T. Shea, J. van Zeijts, E. Barsotti, J.Crisp and B. Fellenz, “The RHIC Wall Current Monitor Sys-tem”, Proceedings of PAC’99.[6] W. Akers, “An Object-Oriented Framework for Client-Server Applications”, Proceedings of ICALEPCS’97.[7] M. Bickley, B. Bowling, D. Bryan, J. van Zeijts, K. Whiteand S. Witherspoon, “Using Servers to Enhance ControlSystem Capability”, Proceedings of PAC’99.[8] T. Satogata, K. Brown, F. Pilat, A. Alai Tafti, S. Tepikianand J. van Zeijts, “The RHIC/AGS Online Model Environ-ment: Design and Overview”, Proceedings of PAC’99.[9] J. Kewisch, “Implementation of Ramp Control in RHIC”,Proceedings of PAC’99.[10] J. Kewisch, J. van Zeijts, S. Peggs and T. Satogata, “RampManagement in RHIC”, Proceedings of PAC’99.[11] S. Hancock, A. Jansson, M. Lindroos, “Tomographic Re-construction of Transverse Phase Space from Turn-by-TurnProfile Data”, Proceedings of PAC’99.482

CDEV Generic Servers for RHIC Commissioning and Operations

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