1. Control System Overview J. Frederick Bartlett Fermilab June 1,1999

2. Outline  Introduction  EPICS Architecture  Channel Access  Scanning  Database Access Levels  Process Variables  Detector Access

3. The DØ Control System  History  Run I - CDAQ Built at DØ VMS and Pascal  Platform Independence Decree  Run II - EPICS Shared with HEP Community Runs on many platforms  The Standard (Control) Model  Operator Interface (OPI)  Local Area Network (LAN)  Input/Output Controller (IOC)

4. The Standard Model OPI IOC OPI IOC LAN

5. Operating Systems  OPI (Host)  Operating System UNIX (including Digital UNIX) Linux Windows NT  IOC (Front End)  Operating System VxWorks Windows NT (Portable CA only) Linux (Portable CA only)  Platforms Motorola 68K (MVME-162) Motorola Power PC (MVME-230x) Intel (Portable CA only)

6. EPICS Characteristics  Maintained by HEP and astronomy community  Tools and building blocks for a control system  Distributed database  Scalable architecture  OPI’s and IOC’s may be added dynamically  Channel Access (CA) servers and clients  Event driven  Portable CA Server Written in C++

7. EPICS Characteristics  High performance (records processed per second)  MVME-162 (68K) >5000  MVME-230x (Power PC) >50000  Extensive collection of applications  Database editors  Display programs  Alarm handler  Archiver  Many more

8. EPICS Channel Access  Channel access provides network transparent access to IOC databases  CA Services  Search - Find a process variable (PV) by name  Get - Get a PV value + optional information  PUT - Change the value of a PV  Add Event - Add a change-of- state callback to a PV

9. EPICS Channel Access  Items returned with a GET  Value String Integer (char, short, int, long) Floating point (float, double) Enumerated menu string  Optional Status and severity Time stamp Graphics and alarm limits Control limits  Channel access transforms  numeric formats  native types

10. Asynchronous  Provides a callback mechanism for change of state  Alarms  Value change Any Deadband Archival

11. EPICS IOC Components Channel Access Database Access Record Support Device Support Driver VME Scanners DB Load Ethernet LAN IOC Database

12. OPI Components User Application Ethernet LAN Channel Access Client Channel Access Client EPICS File Extractor Hardware Database Hardware Database EPICS.DB File EPICS.DB File CA Interface Channel Access Server Channel Access Server DØ Project

13. Scanning  Periodic - Process at a periodic rate  Standard 0.1, 0.2, 0.5, 1, 2, 5, 10 seconds  DØ may add other periods  Event - Process when an event is posted  255 events  Begin run, End run,...  I/O Event - Process on an external interrupt  Passive - Process only when requested

14. Database Access Levels - Record  Record  Provides a generic user view of a device + attributes  Simple records may be linked to provide complex behavior rm AD00 DA00 ai INP VAL ao OUT VAL

15. Database Access Levels - Record  Record  Monitors Alarm conditions Change of value  Transforms Linear scaling Table look-up  Sub-field operations (shift and mask)

16. Database Access Levels - Record  Record  Types Value related  ai and ao - Analog  bi and bo - Boolean  longin and longout - Binary  mbbi and mbbo - Multi-bit fields  stringin and stringout - Character strings  waveform - Block (array) input  calc - General expression evaluation  dfanout - Data replication

17. Database Access Levels - Record  Record  Types Functional  subroutine - Procedure call  timer - Time delay  fanout - Scan propagation  seq - Sequence ordering  event - Event generation Complex  pid - Close-loop controller  histogram - Frequency counts  steppermotor - Positioning  scan - Peak finding

18. Database Access Levels - Device  Device  Transforms device-specific properties to record-specific requirements  Types Bus-specific  VME  MIL-1553B  GPIB  CANBUS  CAMAC

19. Database Access Levels - Device  Device  Types IOC-internal  Soft (linked to another record)  Symbolic (linked to global object)  Function (call interface)  IOC resource measurement Detector-specific  Rack monitor  High voltage  SMT sequencer

20. Database Access Levels - Driver  Driver  Required when a device generates interrupts  DØ uses MIL-1553B bus

21. Process Variables  Application programs access process variables (PV)  A PV is associated with an instance of an EPICS record  EPICS records and, therefore, PVs have many fields (properties) that control its behavior  A field name is usually four characters or less and is always upper case

22. Process Variables  D0 PV naming convention  Concatenation of fields bounded by separators Fields  Detector - i.e. CALN (calorimeter north)  Device - i.e. HV (high voltage channel)  Locator - i.e.  Attribute - i.e. CUR (current)  Field - i.e. HIHI (high alarm limit) Separators  underscore (_)  slash (/)  dot (.)

23. Process Variables  D0 PV naming convention  Examples CALN_HV_001/CUR.HIHI CTL_IOC_11/CPU MUO_PDT_231/ADC

24. Detector Access  Detector component  Calorimeter Central, North, South ICD  Central Fiber Tracker Barrels and Disks Central and Forward Preshower  Forward Proton Detector  Luminosity Monitor  Silicon Microstrip Tracker  Silicon Track Trigger (future)  MUON Central and Forward

25. Detector Access  Accelerator  Gateway link to ACNET system  Data access only  Cryogenics and Gas  Gateway link to DMACS system  Data access only