1. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,1 Detector Control System H.J Burckhart, CERN u Motivation and Scope u Detector and Requirements u Architecture and Functions u Front End System u Practical Work u Summary

2. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,2 Motivation u Detector is too complex to be controlled manually u Each expert covers only a (small) part of the experiment u Expertise gets lost with time u It is important to detect problems early u Possibility is needed to bring the detector automatically in a safe state

3. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,3 Motivation (…) … and also... u Find the original cause of the problem u Give “forecast” of problems about to come up …and perhaps in the end… u Correct problems automatically

4. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,4 Scope u Operate the experiment in a homogenous way u Control all subdetectors u including magnets, cryogenics, etc. u Interface to infrastructure and services u electricity distribution, cooling, ventilation,cryogenics u Interact with the LHC machine u luminosity, background, radiation, beam dump, injection inhibit, etc. u Cover the full range of operation u shift operator expert interaction u Take care of the operational safety of detector

5. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,5 Scope (...) u Present the global safety status to the operator u Provide a good connection to DAQ, but keep operational independence u Promote standardization amongst subdetectors u resources, maintenance u Enable evolution from a (small) stand-alone system to the integrated operation in the final experiment

6. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,6 Scope (...) DCS is not responsible for: u safety of personal u ultimate safety of equipment u hardwired interlocks, PLC DCS is not concerned with physics events: u monitoring of physics data quality u control of physics data flow

7. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,7 Scope (...) Important rules: u DCS is the mandatory tool for all actions of the operator on the detector u DCS is mandatory for the presentation of all error messages and alarms to the operator

8. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,8 Detector Organization

9. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,9 Detector Time Scale u R&Dnow u “Module 0” testnow  u mass production1999  u (pre-) assembly2000  u calibration2000  u installation2003  u physics data taking2005 => each phase has controls needs

10. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,10 Selected Requirements Only selected points which are special as compared to industrial controls are discussed here: u capability for stand-alone controls of sub-systems u easy integration of sub-systems in the overall system u robust, minimal operation e.g. also during power cut u flexible (control procedures change) u basic operation independent of DAQ system u good connection to DAQ (information exchange, data base, etc.)

11. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,11 Selected Requirements (…) u Critical functions must be automated, no operator intervention needed u intuitive user interface (no trained operators) u operation of front end electronics in magnetic field u radiation environment u low power dissipation

12. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,12 Architecture Hierarchically organized in layers (like the detector): u Supervisor u GUI, alarms, logging, etc. u Local Control Station (LCS) u autonomous supervision of part of experiment u Programmable front end system u PLC, Fieldbus nodes u Sensors and actuators u temperature, valve, etc.

13. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,13 Architecture

14. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,14 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”

15. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,15 Functions u On-line status display u alarm handling u history plots u data logging u command logging u incident logging

16. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,16 Functions (...) u operator or event driven execution of expert-defined procedures u state transition, calibration, shut down, etc. u operator assistance u help facility, suggestion for actions, problem analysis u remote (restricted) access via network

17. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,17 Functional Architecture

18. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,18 Front End System Requirements: u Radiation Tolerance u selection of COTS u over-design performance, allow for degradation u operate at lower values than specified u install at protected and accessible places u replace after n years u Operation in magnetic field u no coils, chokes, transformers, DC/DC u remote power u Distributed cluster of I/O points

19. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,19 Front End System (…) Solutions: u Fieldbus: u “simple” cable bus connecting “intelligent” nodes using a well defined protocol u wide range (sensor bus, device bus, LAN) u many industrial standards u many industrial products (chip devices, drivers network management) u characteristics: robustness, bandwidth, topology, length, openness, determinism, bus mastership, error handling, redundancy

20. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,20 Front End System (…) u Programmable Logic Controller (PLC) u simple program structure (one loop, interrupts) u robust u deterministic u dedicated programming environment u connection via LAN and/or Fieldbus u proprietary u flexibility limited

21. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,21 Front End System (…) u Fieldbus and PLC suited for front end system u distributed I/O concentrator u remote diagnostics (no access) u local low level control tasks u local data treatment and reduction u Standardization across LHC experiments u CERN selected Fieldbuses: CAN, Fip, Profibus u Fieldbus nodes u general purpose (ADC, digital I/O, …) u purpose built (chamber controls, rack controls, …) u Fieldbus devices (HT systems, crates, … ) u PLC (magnets, gas, cryogenics, … )

22. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,22 Practical Work CERN Joint Controls Project (JCOP): u Collection of requirements u high level architecture u investigation and evaluation of commercial control system u generic controls of subsystem and devices ( HV, racks, gas, … ) u Fieldbus HW and SW u CAN u CanOpen u LMB

23. DCS LEB Workshop ‘98, Rome, Detector Control System, H.J.Burckhart,23 Summary u Hierarchical controls architecture u Commercial solutions (HW, SW) u Fieldbus and PLC very suited for lowest level u Standardisation across LHC experiments (and machine !)