International Standards for Open Distributed Automation

Transcription

1 International Standards for Open Distributed Automation presented at NSF Workshop on Logic Control for Manufacturing Systems University of Michigan Ann Arbor, MI USA by JAMES H. CHRISTENSEN, Ph.D. Senior Principal Engineer Rockwell Automation JHC/ p. 1

2 The Challenge of of Agile Manufacturing Past The Vision (Iacocca Institute, 1991) Production to Order Lot/Batch size > 1 Unit Information intensive "Reprogrammable, reconfigurable, continuously changeable" Present The Reality Production to Order Possible Order-to-delivery delay 3-6 months(cars), 1 week (PCs) Near Future Japanese Vision "3-day car" Toyota/Canada (planned) "5-day car" (limited customizability) JHC/ p. 2

3 The Challenge to to Automation Systems Agility Requires Dynamic Reconfiguration! Physical Reconfiguration Requires Distributed Automation Logical Reconfiguration Dynamic Reorganization of Control Plans Minimum Human Intervention (zero preferred) Maintain Configuration Control Not just Parameterization! Leads to Large, Complex Software Modules Reduces Distributability, Flexibility, Reliability JHC/ p. 3

4 Centralized Programmable Configurable PLC IEC Thesis INTERNATIONAL STANDARDS FOR OPEN DISTRIBUTED AUTOMATION An Distributed Architectural Automation Dialectic agility distributability Synthesis DCS IEC Distributed Configurable Antithesis Function Blocks IEC programmability agility Agile Manufacturing agility distributability configurability programmability JHC/ p. 4

5 Issues in in the Architectural Dialectic Execution scheduling Communication/execution interaction Response time requirements Alternative algorithm selection State machine design Software encapsulation and reuse Agility ( Dynamic Reconfiguration) JHC/ p. 5

6 IEC Modern Software Engineering for Automation and Control Encapsulation/Reuse Mechanisms Function Blocks, Functions, Data Types, Programs Application-adapted Languages Ladder Diagram (LD) for logic control ( power flow ) Function Block Diagram (FBD) for regulatory control ( data flow ) Sequential Function Chart (SFC) for state-machine control ( internationalized GRAFCET ) Structured Text (ST) for information processing Instruction List (IL) for assembly-level programming A Mature, Internationally Adopted Standard First edition 1993 Second edition 2000 JHC/ p. 6

7 Software Encapsulation and Reuse in in IEC BOOL TIME DEBOUNCE IN OUT DB_TIME BOOL External Interface Specification Control Algorithm Specification IN DB_TIME ON_TMR TON IN PT OFF_TMR TON IN PT Q ET Q ET DB_FF SR S1 Q1 R OUT IN / DB_TIME IN DB_TIME OFF_TMR TON IN PT Q ET ON_TMR TON IN PT Q ET OUT (R) OUT (S) JHC/ p. 7

8 State Machine Control in in IEC Sequential Function Charts (SFCs) initial step action qualifier OFF R OUT IN transition condition action DONE& NOT IN WAIT_ON step DONE& IN D DB_TIME DONE ON S OUT DONE& IN WAIT_OFF NOT IN DONE& NOT IN D DB_TIME DONE JHC/ p. 8

9 Sequential Function Chart (SFC) Features Action Qualifiers No. Qualifier Explanation Sequence Selection 1 None Non-stored (null qualifier) 2 N Non-stored 3 R overriding Reset 4 S Set (Stored) 5 L time Limited 6 D time Delayed 7 P Pulse 8 SD Stored and time Delayed Simultaneous Sequences 9 DS Delayed and Stored 10 SL Stored and time Limited 11 P1 Pulse (rising edge) 12 P0 Pulse (falling edge) JHC/ p. 9

10 Centralized System Configuration in in IEC CONFIGURATION RESOURCE RESOURCE TASK TASK TASK TASK PROGRAM PROGRAM PROGRAM PROGRAM FB FB FB FB GLOBAL and DIRECTLY REPRESENTED VARIABLES ACCESS PATHS Communication function JHC/ p. 10

11 Distributed Configuration in in IEC (Physical View) H1 Fieldbus Segment # 3 Control Room PC LT 111 LT 112 Green Liquor Storage LT 101 H1 Fieldbus Segment # 2 Re-Burned Lime Purchased Lime DT 109 FT H1 Fieldbus Segment # 1 FT 102 AT 103 IP 102 CV-101 A/O IP 104A Heater IP 104B Cooler SC TT 104 TT 105 SC AT 106 SC AT 107A AT 107B LT 108 SC JHC/ p. 11

12 Distributed Configuration in in IEC (Logical View) AI ISEL PID AI AI LL AI PID RATIO AO AT107B HS107 AIC107 AIC106 FRC103 SC103 AT107A AT103 AY103 AT106 AI PID AO FT102 FIC102 IP102 FT 102 FIC 102 IP 102 FRC 103 CV-102 A/O AC 106 AY SC HS 107 AT 103 AT 106 AIC 107 AT 107A AT 107B Conductivity JHC/ p. 12

13 Distributed Configuration in in IEC (Scheduling View) JHC/ p. 13

14 Basic Concepts of IEC Distributed applications Event and data interfaces Software encapsulation and reuse Event-driven state machines Service interfaces Management services Software portability JHC/ p. 14

15 Distributed Applications Event flow Data flow Communication network(s) Device 1 Device 2 Device 3 Device 4 Application A Appl. C Application B Controlled process JHC/ p. 15

16 Event and Data Interfaces Event inputs Event outputs Event flow Event flow Data flow Data flow Event/Data Associations Data inputs Data outputs JHC/ p. 16

17 Software Encapsulation and Reuse in in IEC Basic Function Block Types EI variables EO variables Execution Control Chart Type identifier Algorithms (IEC ) Internal variables Input variables Output variables JHC/ p. 17

18 Software Encapsulation and Reuse in in IEC Composite Function Block Types Functional composition Reusable Atomic (not distributable) Event inputs Event outputs Execution Control Type identifier JHC/ p. 18 Input variables Output variables

19 Software Encapsulation and Reuse in in IEC Adapter Interfaces provider acceptor EO EI EI EO DO DI plug socket DI DO adapter connection Reduce diagram clutter Simplify transducer interface Capture patterns of interaction JHC/ p. 19

20 Event-Driven Execution Control 2 Execution control 8 function Algorithm Scheduling function = sampling JHC/ p. 20

21 The Execution Control Chart (ECC) An Event-Driven State Machine START EC initial state 1 EC transition INIT INIT INIT INITO EX 1 MAIN EC action MAIN EXO event EC state algorithm JHC/ p. 21

22 IEC Device Model Device = Container for Resources Device provides Communications & Process Interfaces Communication link(s) Device boundary Communication interface(s) Resource x Resource y Resource z Application A Application C Application B Process interface(s) Controlled process JHC/ p. 22

23 IEC Resource Model Resource schedules & executes FB algorithms Resource maps Communications & Process I/O Functions to Service Interface Function Blocks Communication mapping Communication functions Local application (or local part of distributed application) Events Service Interface Function Block Data Algorithm Service Interface Function Block Process mapping Process I/O functions Scheduling Function JHC/ p. 23

24 Service Interface Function Blocks Access to Resource functionality Modeled as sequences of service primitives per ISO/IEC TR8509 INIT REQ INITO CNF INIT RSP INITO IND BOOL XXXXXX QI QO PARAMS STATUS BOOL BOOL YYYYYY QI QO PARAMS STATUS BOOL SD_1 SD_m RD_1 RD_n SD_1 SD_m RD_1 RD_n (application-initiated transactions) application resource (resource-initiated transactions) resource application INIT(+) INIT(+) PARAMS INITO(+) STATUS REQ(+) SD_1,...,SD_m CNF(+) RD_1,...,RD_n STATUS INIT(-) INITO(-) STATUS service initiation data transfer service termination t service initiation data transfer service termination PARAMS INITO(+) STATUS IND(+) RD_1,...,RD_m STATUS RSP(+) SD_1,...,SD_n INIT(-) INITO(-) STATUS JHC/ p. 24

25 Communication Service Interfaces Publish/Subscribe Model INIT REQ INITO CNF INIT RSP INITO IND BOOL FB_PUBLISH QI QO PARAMS STATUS SD_1 SD_m BOOL BOOL FB_SUBSCRIBE QI QO PARAMS STATUS RD_1 RD_m BOOL INIT(+) PARAMS INITO(+) ~ INIT(+) PARAMS INITO(+) REQ(+) SD_1,..., SD_m CNF(+) ~ IND(+) RD_1,..., RD_m RSP(+) JHC/ p. 25

26 Communication Service Interfaces Client/Server Model INIT REQ INITO CNF INIT RSP INITO IND BOOL FB_CLIENT QI QO PARAMS STATUS RD_1 SD_1 RD_n SD_m BOOL BOOL FB_SERVER QI QO PARAMS STATUS SD_1 RD_1 SD_n RD_m BOOL FB_CNXN_STATUS INIT(+) PARAMS INIT(+) PARAMS INITO(+) INITO(+) REQ(+) SD_1,..., SD_m CNF(+) RD_1,..., RD_n IND(+) RD_1,..., RD_m RSP(+) SD_1,..., SD_n JHC/ p. 26

27 A Device Management Service Interface Command syntax examples CREATE functionblockinstance CREATE functionblocktype QUERY datatypename CREATE connection START functionblockinstance STOP functionblockinstance DELETE connection DELETE functionblockinstance JHC/ p. 27

28 A Remote Device Management Model JHC/ p. 28

29 System Management Model JHC/ p. 29

30 Open Distributed Systems The The IEC IEC Vision KEY Existing & Normative in IEC Existing but non-normative in IEC To be done Engineering Toolsets Project Repository import XML PORTABILITY Standard management protocols CONFIGURABILITY DeviceNet EDSs Fieldbus DDs etc. Standard data transfer protocols INTEROPERABILITY Libraries IEC IEC IEC Application Frameworks JHC/ p. 30 Distributed intelligent devices & controllers

31 Engineering Tool Models JHC/ p. 31

32 IEC Project Status & Future IEC , Architecture PAS (Publicly Available Standard) issued for Voting IEC , Engineering Task Support 2nd CD (Committee Draft) issued for Technical Review PAS projected year trial use period Incorporate lessons learned from trial implementations DIS projected Home Page ftp//ftp.cle.ab.com/stds/iec/sc65bwg7tf3/html/news.htm JHC/ p. 32

33 IEC Holonic Systems Technology The Missing Link to to Agility Holons negotiate and coordinate tasks via Cooperation Domains. Tasks are perfomed by IEC Applications, generated on the fly. JHC/ p. 33

34 IEC Parent organization IEC Working group TC65/WG6 Goal Standard model (function blocks) for control encapsulation & distribution Started 10/90 Trial period Completion 2003 ftp//ftp.cle.ab.com/stds/iec/sc65bwg7tf3/html/news.htm Holonic Manufacturing Systems (HMS) Parent organization IMS Working group HMS Consortium Goal Intelligent manufacturing through holonic (autonomous, cooperative) modules Feasibility study 3/93-6/94 First phase 2/96-6/00 Second phase 6/00-6/03 http//hms.ifw.uni-hannover.de/ requirements Controls architecture Agile systems architecture JHC/ p. 34

35 An Infrastructure for HMS Engineering Component Repositories Standards Repositories Template Repositories SW Tool Repositories Repository CD SW Tool Cluster CD Solution/ Template Developers Tool/ Component Developers SW Tool Cluster CD Manufacturing CD JHC/ p. 35 Manufacturing CD (CD=Cooperation Domain, H=Holonic Controller, M =Machine) H3 M3 H2 M2 H1 M1

36 An HMS Engineering Workstation CD = Cooperation Domain HD = Holonic Device HR = Holonic Resource Repository CD "I need a template for a paint shop" Tool #1 HR Repository Agent HR SW Tool Cluster CD SW Workstation HD Tool #2 HR User Agent HR System Manager HR "Get the tools and components I need to build the paint shop" "By the way, what standards apply?" Paint Shop CD HD HD HD JHC/ p. 36

37 The Holon An Autonomous, Cooperative (sometimes Physical) Agent Cogitoque coopero, ergo sum JHC/ p. 37