1. CMS – The Detector Control System
Yi Ling Hwong
ACEOLE Six Month Meeting
This research project is supported by the Marie Curie Initial Training Network
Fellowship of the European Community’s Seventh Framework Programme under
contract number (PITN-GA ACEOLE)
25 June 2018

2. Overview Introduction to the CMS Detector Control System
PVSS and JCOP Framework
Why and how?
Finite State Machine
Tools and Applications
Analysis of current FSM tree
Background and objectives
25 June 2018
Yi Ling Hwong

3. The Detector Control System (DCS)
CMS is a collaboration of more than 35 countries
Control system design and implementation is distributed among collaborators
A need for a central control system
A set of policies managing and governing all activity
Main purpose: ensure the correct operation of the CMS experiment
Scope: all subsystems and its active elements, the electronics on and off the detector and the overall environment
Detector Channels
Front End Electronics
Readout Network
HLT Farm
Storage L0
Experiment Control System
DAQ
DCS Devices (HV, LV, GAS, Cooling, etc.)
External Systems (LHC, Technical Services, Safety, etc)
TFC
Monitoring Farm
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
Illustration inspired by Clara Gasper’s presentation for CHEP 2009
25 June 2018
Yi Ling Hwong

4. The CMS DCS
DCS
The DCS of individual sub-detectors are connected to the central DCS Supervisor
Global Services
7 Sub-Detectors Controls
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

5. Control Technologies from LHC Era
DCS
Technologies
PVSS/JCOP Framework
Layer Structure
Sensors/devices
Field buses & Nodes
PLC/UNICOS
OPC
Communication Protocols
SCADA
VME
DIM
FSM
Commercial
Custom
Experimental equipment
LAN
WAN
Storage
Other systems
(LHC, Safety, ...)
Configuration DB,
Archives,
Log files, etc.
Controller/
PLC
VME
Field Bus
Node
Supervision
Process
Management
Field
Finite State Machine
DEN
Background and Objective
Conclusion
Based on an original idea from LHCb
25 June 2018
Yi Ling Hwong

6. Requirements Large number of devices / IO Channels Need for
DCS
Large number of devices / IO Channels
For CMS - Around 6 million parameters
Distributed over 100 PCs
Need for
Parallel and distributed control system
Hierarchical control
Decentralized decision making
Dev1
Dev2
Dev3
Devn
Devi
SubSys2
SubSysn
SubSys1
DetDcs1
DetDcsN
DCS
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion 6
25 June 2018
Yi Ling Hwong
25 June 2018
Yi Ling Hwong

7. What is JCOP? Stands for “Joint COntrols Project”
DCS
Stands for “Joint COntrols Project”
Grouping of representatives from the 4 big LHC experiments
Offer common experiment components and support (e.g. CAEN, ELMB etc)
Aims to reduce the overall manpower cost required to produce and run the experiment control systems
Reduce knowledge of tools
Interface for non-experts
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

8. What is JCOP Framework? A set of guidelines and tools
DCS
A set of guidelines and tools
Produced in collaboration, components shared
Produced using common tools
Aims for homogeneity
The framework is based on:
SCADA system – PVSS
Device Description (Run-time Database)
Device Access (OPC, Profibus, drivers)
Alarm Handling (Generation, Filtering, etc)
User Interface Builder
Etc …
SMI++
Abstract behavior modeling (Finite State Machine toolkit)
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

9. JCOP Framework
DCS
Covers all levels down to the connection to the hardware
Majority of the framework is provided at the supervisory level
Connection of other front-ends is possible via one of the communication interfaces
OPC, DIM or DIP
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

10. JCOP Framework Components provided by framework
DCS
Components provided by framework
Generic Analog-Digital devices
CAEN Power Supplies
Wiener Power Supplies
ELMB
PS and SPS machine data server
Logical Node/View
Device Editor/Navigator
Trending Tool
Etc
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

11. What is FSM? Abstract representation of the experiment
DCS
Abstract representation of the experiment
Control system is modelled as a hierarchy of FSM
A generic, data-driven mechanism for modelling the functionality of a piece of equipment or a subsystem
A state/command interface between a parent and its children
What state is it in? Is it taking data? Is it in standby? Is it broken? Is it switched off? What triggers it to move from one of these states to another?
Two types of objects are defined:
Control Unit
A software entity that monitors the state of its children
Device Unit
A software entity that represents some hardware
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

12. FSM Model A simple control system modelled using FSM
DCS
A simple control system modelled using FSM
Nodes have only one parent
No horizontal lines
Commands go down, States propagated up
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

13. Control and Device Units
DCS
State Transition Diagram for a CU
State Transition Diagram for a DU
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

14. SMI ++
Logically related objects can be grouped inside “SMI domains” to represent a sub-system
Only one object (top level object) is accessed by other objects
Important attributes: State and Action
DCS
JCOP chose the State Management Interface (SMI ++) product which was developed for the Delphi experiment
SMI = Tool to build a FMS + Expert system
Real world is viewed as a collection of objects behaving as FSM
Represent hardware devices, software tasks or abstract subsystem
SMI ++ objects distributed over various platforms
Communication through DIM
Proxy
Hardware Devices
Obj
SMI Domain
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

15. State Management Language
DCS
A special language is provided for the object description – State Management Language (SML)
Interpreted by a Logic Engine (coded in C++) to drive the control system
An SML file corresponds to an SMI domain
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

16. Device Editor and Navigator (DEN)
DCS
Main interface to the Framework
System management
Configuration and operation of device
Editor and Navigator mode
Hardware, logical and FSM view
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

17. Device Unit Type Configurations
DCS
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

18. Logical Object Type Configuration
DCS
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

19. Navigator Mode View the hierarchy starting from any control unit DCS
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

20. Navigator Mode Partitioning, actions etc DCS PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

21. Background Background of project
DCS
Background of project
Large number of independent teams
High complexity
Very different operational mode
Common problems in developing the FSMs:
Repetitive and redundant logic
Inconsistency (endless loops)
Inhomogeneity
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

22. Objectives Understanding of DCS tools and application
Development of an analysis tool to analyze the FSM trees in the CMS DCS
Optimization and thorough analysis of the current FSM system
Provide a mechanism to ensure homogeneity in the FSMs
Development of a visualization program
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

23. Plans Training courses and conferences
DCS
Training courses and conferences
Oracle SQL course (2nd Feb – 4th Feb)
PVSS/JCOP Framework training course (9th Feb – 13th Feb)
FSM course (17th Feb – 19th Feb)
General and professional French course (26th Jan – 3rd April)
Programming in JAVA (27th April – 29th April)
CHEP (23rd Mar – 27th Mar)
RT2009 (10th May – 15th May)
ICALEPCS (12th Oct – 16th Oct) : Abstract submitted
Exportation of FSM into Database
Analysis and building of the complex FSM trees
Possible collaboration with Eindhoven University of Technology
Proposal written and meeting planned
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

24. Conclusion
DCS
The Detector Control System is an integral part of the CMS experiment and is large and complex
A homogenous and coherent control system has been developed using the JCOP framework
PVSS and SMI++ are being used in the framework, and its tools and applications have been proven to be useful and user-intuitive
However, inhomogeneity and incoherence in the FSM development still exist, an analysis tool is foreseen to be developed and implemented
PVSS/JCOP Framework
Finite State Machine
DEN
Background and Objective
Conclusion
25 June 2018
Yi Ling Hwong

25. Thank you for your attention!
25 June 2018
Yi Ling Hwong