LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 1
DCS Detector Control SystemDetector Control SystemH.J Burckhart, CERNH.J Burckhart, CERN
Motivation and Scope Detector and Requirements Architecture and Functions Front End System Practical Work Summary
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 2
DCS MotivationMotivation
Detector is too complex to be controlled manually Each expert covers only a (small) part of the
experiment Expertise gets lost with time It is important to detect problems early Possibility is needed to bring the detector
automatically in a safe state
LEB Workshop ‘98, Rome, Detector
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DCS Motivation (…)Motivation (…)
… and also...
Find the original cause of the problem Give “forecast” of problems about to come up
…and perhaps in the end…
Correct problems automatically
LEB Workshop ‘98, Rome, Detector
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DCS ScopeScope
Operate the experiment in a homogenous way Control all subdetectors
including magnets, cryogenics, etc.
Interface to infrastructure and services electricity distribution, cooling, ventilation,cryogenics
Interact with the LHC machine luminosity, background, radiation, beam dump, injection inhibit, etc.
Cover the full range of operation shift operator <--> expert interaction
Take care of the operational safety of detector
LEB Workshop ‘98, Rome, Detector
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DCS Scope (...)Scope (...)
Present the global safety status to the operator Provide a good connection to DAQ, but keep
operational independence Promote standardization amongst subdetectors
resources, maintenance
Enable evolution from a (small) stand-alone system to the integrated operation in the final experiment
LEB Workshop ‘98, Rome, Detector
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DCS Scope (...)Scope (...)
DCS is not responsible for: safety of personal ultimate safety of equipment
hardwired interlocks, PLC
DCS is not concerned with physics events: monitoring of physics data quality control of physics data flow
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DCS Scope (...)Scope (...)
Important rules:
DCS is the mandatory tool for all actions of the operator on the detector
DCS is mandatory for the presentation of all error messages and alarms to the operator
LEB Workshop ‘98, Rome, Detector
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DCS Detector OrganizationDetector Organization
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 9
DCS Detector Time ScaleDetector Time Scale
R&D now “Module 0” test now mass production 1999 (pre-) assembly 2000 calibration 2000 installation 2003 physics data taking 2005
=> each phase has controls needs
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 10
DCS Selected RequirementsSelected Requirements
Only selected points which are special as compared to industrial controls
are discussed here:
capability for stand-alone controls of sub-systems easy integration of sub-systems in the overall system robust, minimal operation e.g. also during power cut flexible (control procedures change) basic operation independent of DAQ system good connection to DAQ (information exchange, data
base, etc.)
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 11
DCS Selected Requirements (…)Selected Requirements (…)
Critical functions must be automated, no operator intervention needed
intuitive user interface (no trained operators) operation of front end electronics in magnetic field radiation environment low power dissipation
LEB Workshop ‘98, Rome, Detector
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DCS ArchitectureArchitecture
Hierarchically organized in layers (like the detector):
Supervisor GUI, alarms, logging, etc.
Local Control Station (LCS) autonomous supervision of part of experiment
Programmable front end system PLC, Fieldbus nodes
Sensors and actuators temperature, valve, etc.
LEB Workshop ‘98, Rome, Detector
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DCS ArchitectureArchitecture
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 14
DCS Architecture (…)Architecture (…)
Remarks: classification into ‘sub-detectors’ and ‘external systems’ onto which layer to map a of piece of hardware depends on
complexity, functions needed, etc. information flow mainly up/down, not horizontally standardised LCS is the boundary between DCS and
subdetectors propose also a standardised solution for front end system
(Temp. Measurements, power supplies, etc.) standardise gateways for information exchange with
“external system” (LHC machine, cooling/ventilation, electricity distribution, etc.)
interaction with safety system only “one way”
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 15
DCS FunctionsFunctions
On-line status display alarm handling history plots data logging command logging incident logging
LEB Workshop ‘98, Rome, Detector
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DCS Functions (...)Functions (...)
operator or event driven execution of expert-defined procedures
state transition, calibration, shut down, etc.
operator assistance help facility, suggestion for actions, problem analysis
remote (restricted) access via network
LEB Workshop ‘98, Rome, Detector
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DCS Functional ArchitectureFunctional Architecture
LEB Workshop ‘98, Rome, Detector
Control System, H.J.Burckhart, 18
DCS Front End SystemFront End System
Requirements: Radiation Tolerance
selection of COTS over-design performance, allow for degradation operate at lower values than specified install at protected and accessible places replace after n years
Operation in magnetic field no coils, chokes, transformers, DC/DC remote power
Distributed cluster of I/O points
LEB Workshop ‘98, Rome, Detector
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DCS Front End System (…)Front End System (…)
Solutions: Fieldbus:
“simple” cable bus connecting “intelligent” nodes using a well defined protocol
wide range (sensor bus, device bus, LAN) many industrial standards many industrial products (chip<->devices, drivers<->
network management) characteristics: robustness, bandwidth, topology, length,
openness, determinism, bus mastership, error handling, redundancy
LEB Workshop ‘98, Rome, Detector
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DCS Front End System (…)Front End System (…)
Programmable Logic Controller (PLC) simple program structure (one loop, interrupts) robust deterministic dedicated programming environment connection via LAN and/or Fieldbus
proprietary flexibility limited
LEB Workshop ‘98, Rome, Detector
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DCS Front End System (…)Front End System (…)
Fieldbus and PLC suited for front end system distributed I/O concentrator remote diagnostics (no access) local low level control tasks local data treatment and reduction
Standardization across LHC experiments CERN selected Fieldbuses: CAN, Fip, Profibus Fieldbus nodes
general purpose (ADC, digital I/O, …) purpose built (chamber controls, rack controls, …)
Fieldbus devices (HT systems, crates, … ) PLC (magnets, gas, cryogenics, … )
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DCS Practical WorkPractical Work
CERN Joint Controls Project (JCOP): Collection of requirements high level architecture investigation and evaluation of commercial control
system generic controls of subsystem and devices ( HV,
racks, gas, … ) Fieldbus HW and SW
CAN CanOpen LMB
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DCS SummarySummary
Hierarchical controls architecture Commercial solutions (HW, SW) Fieldbus and PLC very suited for lowest
level Standardisation across LHC experiments
(and machine !)