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Control System Overview

J. Frederick Bartlett

Fermilab

June 1,1999

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Outline

Introduction EPICS Architecture Channel Access Scanning Database Access Levels Process Variables Detector Access

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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)

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The Standard Model

OPIOPI

IOCIOC

OPIOPI

IOCIOC

LAN

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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)

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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++

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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

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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

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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

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Asynchronous

Provides a callback mechanism for change of state Alarms Value change

Any Deadband Archival

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EPICS IOC Components

Channel Access

Database Access

Record Support

Device Support

Driver

VME

Scanners

DB Load

Ethernet LAN

IOC Database

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OPI Components

UserApplication

Ethernet LAN

ChannelAccess Client

ChannelAccess Client

EPICS FileExtractor

HardwareDatabaseHardwareDatabase

EPICS.DB File

EPICS.DB File

CAInterface

ChannelAccess Server

ChannelAccess Server

DØProject

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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

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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

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Database Access Levels - Record

Record Monitors

Alarm conditions Change of value

Transforms Linear scaling Table look-up

Sub-field operations (shift and mask)

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Database Access Levels - Record

Record Types

Value relatedai and ao - Analogbi and bo - Boolean longin and longout - Binarymbbi and mbbo - Multi-bit

fieldsstringin and stringout -

Character stringswaveform - Block (array) inputcalc - General expression

evaluationdfanout - Data replication

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Database Access Levels - Record

Record Types

Functionalsubroutine - Procedure calltimer - Time delayfanout - Scan propagationseq - Sequence orderingevent - Event generation

Complexpid - Close-loop controllerhistogram - Frequency countssteppermotor - Positioningscan - Peak finding

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Database Access Levels - Device

Device Transforms device-specific

properties to record-specific requirements

Types Bus-specific

VMEMIL-1553BGPIBCANBUSCAMAC

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Database Access Levels - Device

Device Types

IOC-internalSoft (linked to another record)Symbolic (linked to global

object)Function (call interface) IOC resource measurement

Detector-specificRack monitorHigh voltageSMT sequencer

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Database Access Levels - Driver

Driver Required when a device

generates interrupts DØ uses MIL-1553B bus

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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

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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 (.)

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Process Variables

D0 PV naming convention Examples

CALN_HV_001/CUR.HIHI CTL_IOC_11/CPU MUO_PDT_231/ADC

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Detector Access

Detector component Calorimeter

Central, North, South ICD

Central Fiber Tracker Barrels and Disks Central and Forward Preshower

Forward Proton DetectorForward Proton Detector Luminosity Monitor Silicon Microstrip Tracker Silicon Track Trigger (future) MUON

Central and Forward

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Detector Access

Accelerator Gateway link to ACNET system Data access only

Cryogenics and Gas Gateway link to DMACS

system Data access only