1. Thibault Doucet, GISTR 2012, supervised by Thomas Gamer
Final internship presentation
Redundancy for automation
controllers

2. Agenda
 Introduction
 Company presentation
 What is redundancy ?
 The work done
 Conclusion
© ABB Group
September 17, 2012 | Slide 2

3. Introduction
 Internship subject: « Redundancy for automation controller »
 Objectives:
 Develop several prototypes showing solutions for redundancy
 Study performances, advantages and drawbacks of the various
prototypes
 Supervisor: Dr.-Ing. Thomas Gamer
© ABB Group
September 17, 2012 | Slide 3

4. Company presentation
ABB
 Founded in 1988
 Merge of ASEA and Brown, Boveri and Cie
 Headquarters in Zurich, Switzerland
 Big international company
 145000 employees
 Around 100 countries
 5 main divisions
© ABB Group
September 17, 2012 | Slide 4

5. Company presentation
DECRC
 German Corporate Research Center
 Division Corporate
 R&D projects
 Internal customers
 5 focus areas, 8 research groups
 Group I1: Industrial software technologies
© ABB Group
September 17, 2012 | Slide 5

6. What is redundancy ?
Fault-tolerance & Control systems
 Requirements for certain control systems
 High availability
 Safety
 Fault-tolerance
 « Fault tolerance is the property that enables a system to continue
operation properly in the event of failure of some of its
components. », Ankit Singh
© ABB Group
September 17, 2012 | Slide 6

7. What is redundancy ?
Redundancy
 Way to achieve fault-tolerance
 Duplication of part(s) of the system
 Types of redundancy
 Software Redundancy
 Hardware Redundancy
© ABB Group
September 17, 2012 | Slide 7

8. What is redundancy ?
An example: Standby Redundancy
 Hardware redundancy
 2 controllers
Active
 Active controller controller
Output selector
 Standby controller
Standby
controller
 3 standby modes
 Cold Standby
 Hot Standby
 Warm Standby
© ABB Group
September 17, 2012 | Slide 8

9. What is redundancy ?
An example: Cold Standby Redundancy
 Active controller
 Execution of the application
 State checkpointing Active
controller
 Standby controller
 Powered off Standby
controller
 Switchover process
 Startup of standby
 State update
 Resume execution
© ABB Group
September 17, 2012 | Slide 9

10. What is redundancy ?
An example: Hot Standby Redundancy
 Primary controller
 Execution of the application
 Secondary controller Active
controller
 Powered on
Time
synchronization Output selector
 Execution of the application
 No output Standby
controller
 Switchover process
 Redirection of the ouputs
 Additional requirements
 Time and input synchronization
© ABB Group
September 17, 2012 | Slide 10

11. What is redundancy ?
An example: Warm Standby Redundancy
 Primary controller
 Execution of the application
Active
 Secondary controller
controller
 Powered on State
synchronization
 No-execution
Standby
 Switchover process controller
 Start of execution
 Additional requirements
 State synchronization
© ABB Group
September 17, 2012 | Slide 11

12. The work done
Prototype 1
 Introduction into the topic of redundancy
 Proprietary framework & real time environment
 High emphasis on validation
 Challenges
 Using a prototype framework
 Multi-team work
© ABB Group
September 17, 2012 | Slide 12

13. The work done
Test plan
 Validation process for the prototype
 Design and implementation of the test cases
 Standard: IEEE Std 829-2008
 Use of ALM
 Iterative improvements on the prototype
© ABB Group
September 17, 2012 | Slide 13

14. The work done
Prototype 2
 Different redundancy pattern
 Design for a real industrial controller
 Business trip to Sweden
 High emphasis on modeling and documenting
 Challenges
 Using an extensive code base
 Dealing with limited time
© ABB Group
September 17, 2012 | Slide 14

15. Conclusion
 Interest
 Study of the state of the art
 Technical application with prototypes
 Encountered problems
 Confidentiality issues
 Good formation
 Over a topic
 Over some technologies
 Human and methodological
© ABB Group
September 17, 2012 | Slide 15