Operator Interface for the PEP-II Low Level RF Control System
Contents
1. ring buffers containing the most recent values of the loop parameters are kept as compress records in the database for diagnostic display purposes Standard data base records are provided so that the user can to turn the loop on and off reset the loop to known good values and change the loop period gain maximum actua tor delta allowed in one cycle and any other loop specific constant Bumpless Reboot Bumpless reboot is an IOC software package developed at LANL that saves all input constants states and other data as they are changed and then restores them as part of IOC initialization performed during reboot This package is not part of the standard EPICS distribution but is considered critical for RF station operation and thus was imple mented early in the project To enhance the user interface an optional informational message is now logged when ever an input is changed providing a trail for debugging and determining system usage Since so many fields in the database are modifiable it is unreasonable to save every possible value since this would affect IOC performance due to the overhead of data base monitoring and file IO As a result users must iden tify up front what items they plan to change on the fly As yet this limitation has not proved to be too restricting Message Logging In addition to messages logged by subroutine records se quence tasks and bumpless reboot errors are also logged by various EPICS system a2. OPERATOR INTERFACE FOR THE PEP II LOW LEVEL RF CONTROL SYSTEM S Allison R Claus Stanford Linear Accelerator Center Stanford University Stanford CA 95309 U S A Abstract This paper focuses on the operational aspects of the low level RF control system being built for the PEP II storage rings at SLAC Subsystems requiring major operational considerations include displays for monitor and control from UNIX workstations slow feedback loops and control sequences residing on microprocessors and various client applications in the existing SLAC Linear Collider SLC control system Since commissioning of PEP II RF is currently in progress only those parts of the control system used during this phase are discussed is detail Based on past experience with the SLC control system it is expected that effort expended during commissioning on a solid user interface will result in smoother transition to full reliable 24 hour a day operation I INTRODUCTION The PEP II RF system 1 consists of 5 klystrons each with 4 cavities for the high energy ring HER and 3 klystrons each with 2 cavities for the low energy ring LER Currently two of the HER RF stations are undergoing commissioning For controls each RF station has a VXI crate containing a VXI based microprocessor running Vx Works Allen Bradley AB VME scanner card and a collection of custom VXI modules used for low level RF controls monitoring and machine protection on arc an
3. User s Manual 2 4 March 1997 5 Stein et al Data Exchange from Allen Bradley PLC Based Systems to EPICS ICALEPCS October 1995 2472
4. d power faults Outside the VXI crate AB hardware is used for both the high voltage power supply HVPS and machine protection on slower changing inputs UNIX workstations and a DEC computer are used for the operator interface and higher level applications During commissioning UNIX workstations are the primary X terminals in use During operation other types of X terminals some with touchpanels will supplement the workstations The interface between the user and the hardware is constructed using the Experimental Physics and Industrial Control System EPICS took kit To meet requirements additional software is being developed in house or at other labs to supplement the standard EPICS software distribution The tasks running on each RF VXI processor also known as an Input Output Controller IOC provide data scanning for updating the database data archival for bumpless reboot message logging control loops state transitions calibration sequences and channel access allowing other hosts to access the database In addition to software on the IOC other EPICS based packages are used on the UNIX stations for client operator interface OPI applications including the EPICS display editor and manager EDD DM a stripchart tool 0 7803 4376 X 98 10 00 1998 IEEE and various channel access tools Existing SLC control system applications are being modified to perform channel access and to incorporate EPICS messages into the SLC
5. d to be valuable for quick debugging and verification during commissioning An example display follows Override 1000 uz HVPS Voltage kY 65 27 HVPS Current Amp 15 44 i HVPS Power kW p 1008 Se 6 8e 09 7 0e 09 5 7e 09 p 895 pre 86 iz el a E 30 00 20 00 a ee a ne ee ee ee eee ries are available with one button push An RPC server task was developed to receive messages from the IOCs and forward them to the SLC message handling facility The existing message display system with its rich set of fea tures can then be used to search for and list specific mes sages V ACKNOWLEDGEMENTS We would like to acknowledge P Corredoura T Himel D Kerstiens K Krauter R Sass and M Zelazny for their efforts in either specifying or implementing the EPICS user interface We would like to thank the SLC controls group for their help and patience during integra tion and the EPICS collaboration for their invaluable assistance REFERENCES 1 P Corredoura et al Low Level System Design for the PEP II B Factory Proceedings of the 1995 IEEE Particle Accelerator Conference 2 P Corredoura et al Commissioning Experience with the PEP II Low Level RF System these Proceedings 3 Dalesio et al The Experimental Physics and Industrial Control System Architecture Past Present and Future ICALEPCS October 1993 4 P Stanley EDD DM
6. een size To match similar capabilities on the SLC control system the user now has the ability to select a printer or save to file New kinds of buttons for selecting files toggling a binary state and printing have been added The name behind any dynamic button is now made visible on request and put into the workstation paste buffer for use by other applica tions The same displays are used whenever possible for all stations with distinctions defined by macros Except for diagnostic displays all displays have a similar look and are consistent in the use of color coding button and data display sizes and placement of common items on all dis plays like the title exit print and help buttons The dis plays are hierarchical so the user starts at the high level displays which show overall summaries and statuses and works down to the lower level displays providing more detail for a smaller part of the machine In general when going from one display to another the parent display is killed to prevent clutter and manage resources Buttons on the lower level displays allow the user to go back up Since displays must work on touchpanel X terminals by people standing in a crowded and cluttered control room the mouse usage is minimized by employing more realestate for display and control selections rather than using mousedriven popup or pulldown menus The size of many control buttons and spacing between buttons are made for fingers rather
7. message log II IOC SOFTWARE The RF IOC software was developed for an efficient and easily maintainable hardware interface For the custom VXI modules one EPICS record per module was developed encapsulating all data and functions of that module For the AB interface software developed at APS and LANL was implemented as is or modified slightly for the machine protection and high voltage systems For the AB stepper motor card device support software for the existing stepper motor record was developed Additional software on top of this lower level interface is being added to allow a user without detail knowledge of the control hardware to operate the RF station The EPICS database is the bedrock of the RF control sys tem Some subsystems such as machine protection monitoring are implemented with just database records To allow quick changes with minimal software impact all RF stations use the same database and startup files with distinctions defined by environment variables The follow ing packages are being added to supplement the basic data base and provide a more usable system Subroutine Calculation and Sequence Records Subroutine and calculation records provide data processing and analysis An example of their usage is in the calcula tion of phase power and other related parameters from input in phase and quadrature count values at 24 locations in the RF station at 2 hz Also for each component of the RF station reco
8. nd database tasks The mes sage logging mechanism provided by the standard EPICS distribution does not integrate well with the existing SLC message logging a system familiar to the users and heav ily used As a result a remote procedure call RPC client task was developed which forwards all messages to a server in the SLC control system HI OPI APPLICATIONS The PEP II control system is built from both EPICS and the SLC control system Both systems are high perform ance distributed database driven systems using microproc essors running real time operating systems and performing control and monitoring of nearby hardware Both provide similar basic client applications such as data archival alarming correlation plots backup and restore and knob bing Since users are already familiar with SLC applica tions the only EPICS UNIX OPI tools enlisted for PEP If are those with either no equivalent or with highly desirable features not available in the SLC control system Currently these tools include EDD DM from LANL and a strip chart tool from TJNAF EPICS channel access tools are also used by MATLAB data analysis programs written and used only by the RF engineers EDD DM EDD DM provides real time graphical displays Though already rich in options additional features are being added to EDD DM by LANL to meet PEP II requirements Be cause of the variety of X terminals in use displays are now automatically scaled depending on scr
9. olt aon Cavity D Volt ky 677 D E 2 21 STRIP CHART TOOL The strip chart tool is used during commissioning to monitor RF processing parameters such as cavity vac uums and gap voltages Buttons on EPICS display allow users to start a variety of canned strip charts Once active the users may change any plot setup parameter for tailor ing to their specific needs This tool is quite popular and there are plans to allow it access to SLC control system data IV SLC CONTROL SYSTEM Channel access has been incorporated into a subset of SLC control system client applications to access the RF databases EPICS database record naming conventions were developed so that the existing user interface could be adopted with few changes During commissioning the two mostly widely used applications are data archival and message logging Other applications such as configuration save restore correlation plots alarm handling and mul tiknobs will be used later during full operation For data archival a channel access history buffer process was de veloped that periodically samples a subset of RF analog data points and saves them to files in the same format as SLC data The user can then request plots of specific channels for any time period using the existing interface for SLC history Canned plots of the more popular histo the value which the user can select to get detailed database and other related information These database displays have prove
10. rds providing summaries of severities and trips are processed on change and allow quick determina tion of trouble spots Sequence records perform a series of simple control steps in a particular order with optional delays Functions performed by sequence records include station reset which executes the 12 steps needed to reset after a trip reinitiali zation of the cavity tuner stepper motors calibration of various system coefficients and DAC update SEQUENCE TASKS For more complex control sequences and loops sequence tasks are being developed instead of a series of subroutine and sequence database records Sequence tasks include one per Work supported by Department of Energy contract DE AC03 76SF00515 cavity for cavity tuning high volt age control for either station processing or to maintain the klystron drive power DAC calibration and station state control for transitioning to a desired run mode such as 2470 OFF ON PARK for allowing beam through the cavities while the station is offline and TUNE or FM for station processing while no beam For all sequence tasks common features are incorpo rated especially for the user interface Metered descriptive error messages are logged on abnormalities such as hard ware errors and trips Informational messages are logged on state changes atlimit conditions and other warnings These conditions are also updated in the database as strings for real time display For control loops
11. than cursors Currently the dis plays have too much information and very few graphics per page convenient for commissioning but not ideal for normal operation since the displays take too long to acti vate and are too dense Colors are limited to a handful and if possible are combined with other attributes such as text and flashing for color challenged users For both summaries and indi vidual items green means OK yellow means warning but with time for action flashing yellow means a trip is im minent red indicates the item is currently tripped and keeping the station off flashing red indicates the item 1s the first to trip the station and magenta means a hardware or software problem Currently all display backgrounds are light colored with informational text in darker colors 2471 though this may change once operation is transferred to the dimly lit control room In general monitored data is displayed in black text with the current status shown using a colored rectangular box around the value A small DB box resides next to HER RF1i2 1 Station In TUNE Auto Reset State Control Tries Left FM OnE Filament Voltage V Filament Current Amp p 4 28 i Filament Time Left Sec 05 O Max Voltaga kr prive Bower v Vacum Level Torr Forward Power kW 701 p as Reflected Power kW pre 43 Stn Volt ky Tuner Posn mm cavity A vort aw x Cavity B Volt kY 613 B poe 2 06 cavity v
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