A Profile for Integrating Function Blocks into the Unified Modeling - PowerPoint PPT Presentation

A Profile for Integrating Function Blocks into the Unified Modeling Language Torsten Heverhagen , Rudolf Tracht Automation and Control, Dept. of Mechanical Engineering, University of Duisburg-Essen, Germany Robert Hirschfeld DoCoMo Euro-Labs, Future Networking Lab, Germany Specification and Validation of UML Models for Real Time Embedded Systems, SVERTS‘03

Overview • Introduction and Motivation – Drilling Example • Function block oriented languages – Matlab/Simulink – IEC 61131-3 – IEC 61499 • Integration of function blocks into UML – Comparison of FBs and Classes – Profile “Functionblockadapters” • Summary and Outlook SVERTS '03 1 TorstenHeverhagen, Torsten.Heverhagen@web.de

Drilling Example • Four steps – Moving to drilling position – Drilling – Cleaning the hole – Moving back SVERTS '03 2 TorstenHeverhagen, Torsten.Heverhagen@web.de

Mathematical Modeling of the Plant ω M u y System Modeling ω = − ω + & ( ) t a ( ) t bu t ( ) y u ϕ = ω & ( ) t ( ) t = ϕ y t ( ) c ( ) t SVERTS '03 3 TorstenHeverhagen, Torsten.Heverhagen@web.de

Control Loop Design • Common structure of feedback control loops • Controller is real-time software – implemented in microcontrollers, PLCs, ... • Plant is real world, but for simulation and testing it is also software y u r e Controller Plant + _ SVERTS '03 4 TorstenHeverhagen, Torsten.Heverhagen@web.de

Simulation of Continuous Time Controllers • For example using Matlab/Simulink™: • Behavior of such blocks can also be described using – z-transfer functions, – statecharts, – ... SVERTS '03 5 TorstenHeverhagen, Torsten.Heverhagen@web.de

Function Block Oriented Languages • Matlab/Simulink • IEC 61131-3 (Languages for programmable controllers) MC_MoveAbsolute – 5 languages AXIS_REF Axis Axis AXIS_REF BOOL Execute Done BOOL REAL Position CommandAborted BOOL REAL Velocity Error BOOL REAL Acceleration ErrorID WORD REAL Deceleration REAL Jerk MC_Direction Direction • IEC 61499 (Function Blocks for Industrial-Process Measurement and Control Systems) – Execution Control Chart (ECC) FB_MoveAbsolute Done EVENT EVENT Execute CommandAborted EVENT Error EVENT – action language from 61131-3 AXIS_REF Axis ErrorID WORD REAL Position REAL Velocity REAL Acceleration REAL Deceleration REAL Jerk MC_Direction Direction SVERTS '03 6 TorstenHeverhagen, Torsten.Heverhagen@web.de

A General Function Block Model • Our working model for the integration of existing FB- languages into UML – interface: input, output, through variables (all static) – internal: static data structures + behavior – type (class) and instance Through Variables Internal Variables Input Output Behavior of the Variables Variables Function Block SVERTS '03 7 TorstenHeverhagen, Torsten.Heverhagen@web.de

Example for Protocols of Function Blocks MC_MoveAbsolute Error ErrorID AXIS_REF Axis Axis AXIS_REF BOOL Execute Done BOOL REAL Position CommandAborted Execute BOOL REAL Velocity Error Done or CA BOOL REAL Acceleration ErrorID input data WORD REAL Deceleration output data REAL Jerk MC_Direction Direction SVERTS '03 8 TorstenHeverhagen, Torsten.Heverhagen@web.de

Example for UML Protocols mc_client / MC_Client / MC_MoveAbsolute wait 1: NewPosition 1: NewPosition ffwd 1.1: Ended 1.1: Ended 2: NewPosition 2: NewPosition fwd 2.1: Ended 2.1: Ended Error dwell S0 3: NewPosition 3: NewPosition Ended NewPosition or rev Timeout 3.1: Ended 3.1: Ended S1 Error wait SVERTS '03 9 TorstenHeverhagen, Torsten.Heverhagen@web.de

Function Block Adapters • Work as programmable protocol adapters between UML protocols and function block protocols • Platform independent • Provided as a UML profile Ended a:MC_Client b:MC_FBA TimeOut Error c mcPort clientPort NewPosition MC_MoveAbsolute Y_Axis Axis Axis Execute Execute Done Done Position Position CommandAborted CommandAborted Velocity Velocity Error Error 2,0 Acceleration ErrorID ErrorID 2,0 Deceleration 0,0 Jerk Direction SVERTS '03 10 TorstenHeverhagen, Torsten.Heverhagen@web.de

Summary and Outlook • High importance of function block oriented languages in industrial control modeling and programming • Combination of UML and function blocks is promising • Function block adapters provide a framework and design patterns for integrating UML and function blocks • Previous work was based on IEC 61131-3 • Current work: – profile Functionblockadapters – extension to function block oriented languages • Outlook: functionblocks.org SVERTS '03 11 TorstenHeverhagen, Torsten.Heverhagen@web.de

Comparison of Function Blocks and Classes • Function Blocks • UML – type – class – instance – instance – internal variables – attributes – internal behavior – one operation/statechart – interface variables – no direct match • this is discussed in the next slide SVERTS '03 12 TorstenHeverhagen, Torsten.Heverhagen@web.de

Discussion of Interface Variables • Comparison to parameters – both have a direction kind (in, inout, out) – but: should be independent of behavior execution • Comparison to attributes – both are independent of internal behavior execution – but: direction kind is missing • Comparison to pins of activities – both are connectable and have a direction kind – but: should be independent of activity execution • Comparison to ports – ports are mightier than interface variables SVERTS '03 13 TorstenHeverhagen, Torsten.Heverhagen@web.de

Using Ports as Interface to Function Blocks «stereotype» «stereotype» Interface FBInterface (from Interfaces) May only contain one signal called ValueChanged «stereotype» «stereotype» Port FBPort (from Ports) May only require one FBInterface «stereotype» «stereotype» FBInPort FBOutPort May only provide one IPLC_Bool IPLC_Bool FBInterface SVERTS '03 14 TorstenHeverhagen, Torsten.Heverhagen@web.de