Eastern Mediterranean University

1
Eastern Mediterranean University
Faculty of Engineering
Department of Mechanical Engineering
Reconfiguring Real-time Holonic Manufacturing
System
Presented By
Reza ABRISHAMBAF
Faezeh YEGANLI
2
Real-time HMS

• Agenda

• Introduction
• IEC 61499 Function Block
• Holonic Manufacturing System
• Real-time Distributed Control System
• Reconfiguration of Real-time Distributed Control
• Case Study
• Application of Virtual Reality

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Real-time HMS

• Introduction

• Manufacturing control systems are required to be
  adaptive and responsive.
• One approach which is closely related to the
  Multi-agent systems is HMS.
• The motivation is the requirement for
  manufacturing systems that can automatically and
  intelligently adapt to changes in the
  manufacturing environment while still achieving
  overall system goals.

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Real-time HMS

• Introduction

• At the low control level of a HMS, especially at
  the level of real-time control, reconfigurable
  holonic controllers are employed (HCs).
• The critical issue for holonic control at this
  level is how the resources of the HMS are to be
  organized dynamically during runtime and how the
  associated controller components are to be
  reconfigured dynamically at the same time.
• Solution
• Real-time distributed control system that can
  benefits of holonic control system.

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• Introduction

• The real-time holonic distributed control
  systems require
• Stability in the face of disturbance (i,e.,
  Sensor or Robot Failure.)
• Adaptability and flexibility in the face of
  change.
• Efficient use of available resource.
• To do so, IEC-1499 Function block (FB) standard
  is employed.
• Lets have a look at PLC first!!

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• Introduction

• A programmable logic controller (PLC) or
  programmable controller is a digital computer
  used for automation of mechatronic processes,
  such as control of machinery on factory assembly
  lines.
• Designed for Multiple Input Multiple Output
  (MIMO).
• Fixed I/O or Modular I/O

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• Introduction

• SIEMENS S7-200, CPU 222.
• 8 Inputs, 6 Outputs.
• 256 Counters Timers.

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• Introduction

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• IEC-61499 Function Block

• A standardization project of IEC Technical
  Committee 65 (TC65) to standardize the use of
  function blocks in distributed industrial-process
  measurement and control systems (IPMCSs).
• Work item approved 1991 assigned to Working
  Group 6 (WG6) 1993
• Experts from USA, Germany, Japan, UK, Sweden,
  France, Italy
• Also responsible for IEC 61131-3 (Programmable
  Controller Languages) and 61131-8 (Programmable
  Controller Language Guidelines)

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• IEC-61499 Function Block

• Distributed applications
• Event and data interfaces
• Software encapsulation and reuse
• Event-driven state machines
• Service interfaces
• Management services
• Software portability

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• IEC-61499 Function Block

dynamically reconfigurable agile !
Common ArchitectureReferenceModel
Function Blocks IEC 61499
Synthesis
distributed configurable programmable
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• IEC-61499 Function Block

• IEC 61499 is composed of 2 IECs standards
  IEC-61131-3 and IEC-61804.
• IEC-61131-3 is Centralized Programming
  Configurable (PLC) with Distributablity property.
• IEC-61804 is Distributed Configurable with
  Programmibility property.
• The result is Distributed Configurable
  Programmable which is common architecture
  reference model.

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• IEC 61499
• Parent organization IEC
• Working group TC65/WG6
• Goal Standard model (function blocks) for
  control encapsulation distribution
• Started 10/90
• Active development 3/92
• Trial period 2001-03
• Completion 2005

• 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

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• IEC-61499 Function Block

Event inputs
Event outputs
Execution Control Chart
Type identifier
Algorithms
(IEC 1131-3)
Internal variables
Output variables
Input variables
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• IEC-61499 Function Block

• Function Block is consist of two main parts Head
  and Body.
• The head of Function Block is Execution Control
  Chart (ECC) which organizes the flow of events
  between the blocks as well as the body control.
• The body of Function Block consists of algorithm
  and the internal data as well as the I/O data.
• The algorithm inside the body operates in
  IEC-61131-3 standards.
• The body will control the resource capabilities,
  scheduling, communication and process mapping.
• Events inputs and outputs are used to synchronize
  function blocks within an application and to
  schedule the algorithms within the function
  block.
• Data inputs and outputs are the interface with
  the external of the function block since internal
  data is hidden.

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• IEC-61499 Function Block

Function Block Execution Model
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• IEC-61499 Function Block

• Relevant data input values are made available.
• The event at the event input occurs.
• The execution control function notifies the
  resource scheduling function to schedule and
  algorithm for execution.
• Algorithm execution begins.
• The algorithm completes the establishment of
  values for the output variables associated with
  the event output.
• The resource scheduling function is notified that
  algorithm execution has ended.
• The scheduling function invokes the execution
  control function.
• The execution control function signals an event
  at the event output.

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• Holonic Manufacturing System

• Holon is an autonomous and cooperative building
  block of a manufacturing system for transforming,
  transporting, storing, and/or validating
  information and physical objects.
• Holon Autonomy is the capability of a holon to
  create and control the execution of its own plans
  and/or strategies.
• Holon Cooperation is the process whereby a set of
  holons develops mutually acceptable plans and
  executes them.
• Holon Self-organization is the ability of holons
  to collect and arrange themselves in order to
  achieve a production goal.
• Holarchy is system of holons that can cooperate
  to achieve a goal or objective.

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• Real-time Distributed Control (Definitions)

• System A collection of devices interconnected
  and communicating with each other by means of a
  communication network consisting of segments and
  links.
• Device An independent physical entity capable
  of performing one or more specified functions in
  a particular context and delimited by its
  interfaces.
• Resource A functional unit having independent
  control of its operation, and which provides
  various services to applications including
  scheduling and execution of algorithms.
• Application A software functional unit that is
  specific to the solution of a problem in
  industrial-process measurement and control. An
  application may be distributed among devices and
  may communicate with other applications.

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• Real-time Distributed Control

• A holon is represented by one or more hardware
  devices and can interact via one or more
  communication networks.
• Each device comprises of one or more resources
  (i.e. processor with memory) and one or more
  interface.
• Interfaces enable the device to interact with
  either the controlled manufacturing process or
  with other devices through a communication
  interface.
• Resources are logical entities with independent
  control over their operations including the
  scheduling of their tasks.
• A resource can be created, configured via
  management model.

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• Real-time Distributed Control

• Applications are networks of function blocks (FB)
  and variables connected by data and event flows.
• Such applications aid the modeling of cooperation
  between the autonomous holons.
• Function blocks receive event/data from
  interfaces, process them by executing algorithms
  and produce outputs, all handled by an event
  control chart.
• Function block algorithms can be written in
  high-level programming language or in the
  IEC-61131 language for PLCs.

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• Reconfiguration of Real-time Distributed Control

• In conventional PLC systems, reconfiguration
  involves a process of first editing the control
  software offline while the system is running,
  then committing the change to the running control
  program.
• When the change is committed, severe
  disruptions and instability can occur as a result
  of high coupling between elements of the control
  software and inconsistent real-time
  synchronization.
• Three types of reconfiguration
• Simple configuration utilizes the IEC 61499
  model to avoid software coupling issues
  during reconfiguration.
• Dynamic reconfiguration uses techniques to
  properly synchronize software during
  reconfiguration.
• Intelligent reconfiguration exploits multi-agent
  techniques to allow the system to reconfigure
  automatically in response to change.

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• Reconfiguration of Real-time Distributed Control

The Reconfiguration Model
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• Reconfiguration of Real-time Distributed Control

• Function block ports (i.e., event and data
  connections) are objects that register with the
  Resource Manager (RM) associated with the
  function block. The resource manager looks after
  the interconnection of function block ports
  (i.e., as is specified by the application) and
  maintains a record of all function block ports in
  a FB Port table.
• The Device Manager (DM) looks after the
  interconnection of the RMs function block ports
  and stores this information in an RM Port table.
• Application Manager (AM) looks after the
  interconnection of the DMs function block ports
  and stores this information in a DM Port table.

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• Reconfiguration of Real-time Distributed Control

• The advantage of this approach is that
  reconfiguration can be managed at various levels
  (i.e., function block, resource, device,
  application) all that is
• required is a map of the new configuration
  (i.e., based on the FB, RM, and DM Port tables).
• This approach allows for the basic
  reconfiguration discussed previously, but does
  not yet address how dynamic and intelligent
  reconfiguration are performed.
• The fundamental difference between basic and
  dynamic reconfiguration is the latters
  recognition of timeliness as a critical aspect of
  correctness.

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• Reconfiguration of Real-time Distributed Control

• Intelligent reconfiguration builds .on dynamic
  reconfiguration (i.e., timeliness constraints) by
  focusing on multi-agent techniques to allow the
  system to reconfigure automatically in response
  to change.
• For example, as part of a fault recovery
  strategy, higher-level agents will manage the
  reconfiguration process using diverse or
  homogeneous redundancy.
• Two approaches to achieve these more advanced
  forms of reconfiguration
• Preprogrammed or contingencies approach.
• Softwiring approach.

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• Reconfiguration of Real-time Distributed Control

• Contingencies Approach
• Contingencies are made for all possible changes
  that may occur.
• Alternate configurations are pre-programmed
  based on the system designers understanding of
  the current configuration, possible faults that
  may occur as well as possible means of recovery.
• Disadvantages
• Inflexibility particularly with respect to the
  handling of unanticipated changes.
• This approach would require constant maintenance
  in order to keep the reconfiguration tables up to
  date.

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• Reconfiguration of Real-time Distributed Control

• Soft-wiring Approach
• FB, RM, DM port tables are connected to the
  Configuration Agent (CA).
• This agent has information of how two FB, RM or
  DM can be connected.
• CA will use this information, for example, to
  connect a new function block with an existing
  function block or to replace an existing one with
  a new while ensuring that the real-time
  requirement are met.
• Advantages
• Its potential to overcome the inflexibility
• Its potential to realize intelligent
  reconfiguration.

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Real-time HMS

• Case Study

System 1
Barcode Reader
Infrared Sensor
5-joints Robot
Conveyor
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Real-time HMS

• Case Study

• System 1 contains Conveyor, Robot, Barcode
  Reader and Sensor.
• At the beginning of the conveyor, there is a
  switch. When a part touch the switch, the
  conveyor will start.
• When a part comes to the system, it will be
  moved by conveyor. There is a barcode reader will
  read the code of the part.
• Depending on the code of the part, the Robot
  will put it in either Machine 1 or Machine 2 or
  to the Conveyor 2 of the system 2.

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• Case Study

System 2
Conveyor
5-joints Robot
Pneumatic Robot
Infrared Sensor
Color Sensor
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• Case Study

• System 2 contains Conveyor, Robot, Pneumatic
  Robot, Color Sensor and Infrared Sensor.
• The system waits until a part from system 1
  arrives.
• When infrared sensor detects a part, the
  conveyor will start.
• Part will be moved till the color sensor, beside
  the color sensor, we have pneumatic robot that
  will take the part or it will be moved until the
  infrared sensor detects it.
• By detecting with infrared sensor, the robot
  will take and put the part in another machine.

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• Case Study (Reconfiguration)

Configuration Agent
Adding a Robot
Cell 2
CA
Cell 1
Robot
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• Case Study

• Case Study (Reconfiguration)

• Methods of Adding a Robot
• To use the common method (Offline Mode).
• To use the predicted table.
• To use the IEC 61499 FB Standard.

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• Case Study

• Case Study (Reconfiguration)

• Adding a Robot
• The aim is to add one Robot the system.
• Cell 1 Cell 2 have their own Function Blocks
  (FB1, FB2,.).
• Function blocks will have information on how
  they can be connected (i.e., their interfaces)
  that is stored by CAS. The CAS will use this
  information, for example, to connect a new
  function block with an existing function block or
  to replace an existing function block with a new
  one while ensuring that the applications
  real-time requirements are met during the
  reconfiguration process. The primary advantage of
  this approach is its potential to overcome the
  inflexibility of the contingencies approach as
  well as its potential to realize intelligent
  reconfiguration.

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• Case Study

• Case Study (Reconfiguration)

For example, if the request for a new
configuration requires upgrading an application
to include more sophisticated functionality, and
the device does not have sufficient processing
resources for this upgrade, the new functionality
may have to be out-sourced. Moreover, even if
the execution of the function blocks tasks are
consistent with the devices schedule and
equipment, the device actor might still decide to
out-source some or all of the new configurations
tasks. For example, this redistribution may be
done to save some of the available resources for
executing tasks associated with a configuration
that is currently under negotiation with the
user.
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• Application of Virtual Reality

• In this section three simulation softwares will
  be presented.
• Virtual Reality
• Rockwell Simulation Model
• MAST (Manufacturing Agent Simulation Tool)

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• Application of Virtual Reality

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• Application of Virtual Reality

• The Design Environment includes the Multi Agent
  System Model.
• The agents are AGVs, Robots, Conveyor,
• The messaging system is based on JAVA/JADE.
• What if each agent is defined based on IEC 61499
  Function Block?

FB
FB
FB
Conveyor
AGV
Robot
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• Application of Virtual Reality

Proposed Multi Agent System Based on IEC 61499
Configuration Agent
Header
Header
Header
Body
Body
Body
Conveyor
AGV
Robot
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• Application of Virtual Reality

• The agents are defined based on IEC 61499 FB.
• The headers of Function Blocks are connected to
  the Configuration Agent.
• The Configuration Agent (CA) contains the status
  of each Function Block and the connection among
  them.
• This configuration system can be based on
  JAVA/JADE or other high level languages.
• In case of device failure, since CA has the
  status of the FBs, it can substitute another
  device instead.
• The whole system is in the Design Environment.

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• Application of Virtual Reality

A holon is represented by one or more hardware
devices, and can interact via one or more
communication networks. Each device comprises of
one or more resources (i.e., processor with
memory) and one or more interfaces. Interfaces
enable the device to interact with either the
controlled manufacturing process (via a process
interface) or with other devices through a
communication interface. Resources are logical
entities with independent control over their
operations including the scheduling of their
tasks. A resource can be created, configured etc
(as part of the systems life-cycle) via a
management model.
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• Application of Virtual Reality

Applications (software functional units
spanning one or more resources and over one or
more devices) are networks of function blocks
(FB) and variables connected by data and event
flows. Such applications aid the modeling of
cooperation between the autonomous holons.
Function blocks receive event data from
interfaces, process them by executing algorithms
and produce outputs, all handled by an event
control chart. Function blocks algorithms can
be written in either high-level programming
languages (e.g., C) or in the IEC 61 131
languages for programmable controllers (e.g.,
Ladder Diagrams, Structured Text). A distribution
model controls how applications are decomposed
while ensuring that every function block is an
atomic unit of distribution.
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• Application of Virtual Reality

Another Simulation Model proposed by Rockwell
Co. It represents a new approach to the
manufacturing oriented agent based control and
simulations that enables the integration of
agents with the currently used industrial control
hardware architecture and simplifies the transfer
of the agent-control developed initially for
simulation purposes to the actual physical
control.
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• Application of Virtual Reality

• Physical Process is the physical entity like
  AGV, Robot.
• PLC contains Data Table which has the status of
  each physical entity in the Tags(A1_tagA,
  A1_tagB).
• Agent Control contains the corresponded
  Physical Component Agent.
• Emulation used to simulate the system , like
  Matlab, Arena.
• Visualization providing graphical view of the
  system.
• By the combinations of the mentioned blocks, an
  Agent Based Simulation System will be obtained.

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• Advantage of Virtual Reality

• One of the important advantages of such a real
  time system is that the system can be
  reconfigured online.
• For instance, when a new sensor is added at
  runtime to the conveyor based
• transportation system, a set of new elements are
  dynamically created and added to corresponding
  subsystems sharing the data-table the sensor
  agent is added to the agent control part, the
  sensor emulation unit is added to the emulation
  subsystem and the sensor visualization element is
  added to the visualization module. Concurrently,
  the tag values corresponding to the state of the
  sensor are added to the data-table to be shared
  by these new elements.

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• Advantage of Virtual Reality

• Another Advantage
• The important feature of the proposed interface
  is smooth shift of the control functionalities
  from the agent based simulation towards the
  real-life control. It allows replacing of the
  emulation subsystem with the real physical
  manufacturing equipment by preserving the same
  tag names referring to the sensor and actuator
  values. Thus it is not necessary to do any
  modifications in the agents or in the
  visualization subsystem.

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• Application of Virtual Reality

• MAST (Manufacturing Agent Simulation Tool)
• As result of the research effort under the
  Intelligent Manufacturing Systems (IMS) framework
  Rockwell Automation in cooperation with different
  partners has designed and developed MAST
  (Manufacturing Agent Simulation Tool) a graphical
  visualization tool for multi agent systems. The
  main target is the materials handling domain and
  it is built on the JADE standard FIPA platform.
  In MAST, the user is provided with the agents for
  basic material handling components as for
  instance manufacturing-cell, conveyor belt,
  diverter and AGVs. The agents cooperate together
  via message sending using common knowledge
  ontology developed for material handling domain.

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• Application of Virtual Reality

• MAST (Manufacturing Agent Simulation Tool)
• MAST represents the state of the art in graphical
  simulation tools for modeling and simulation of
  multi agent systems in manufacturing control,
  however and due to the fact that only material
  handling systems are targeted the tool does not
  cover complex application from a 3-D geometric
  viewpoint such as the robotic manipulation.

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• Advantage of Virtual Reality

• Virtual Reality in Real-time system
• Solving problems before being employed in
  practical manufacturing.
• Preventing costly mistakes.
• Online analysis of reconfiguration before being
  engaged to the reality.
• De-centralized manufacturing control
  architecture.
• MAST Rockwell Model are simulation models, it
  means that there is no re-configurability
  control, however in VR reconfiguration can be
  performed.

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• Advantage of Virtual Reality

One of the most important advantage of VR in real
time is online analysis. For instance, in a
system, one robot needs to be reconfigured. With
the help of function block, the reconfiguration
can be performed in real time, however what if
this reconfiguration is inconsistent with the
system. By using virtual reality, the
reconfiguration in virtual environment can be
performed to observe any inconsistency. Another
example can be the addition of a sensor. Recall
that adding a physical entity would require a new
function block. This new function block will be
added using Configuration Agent. In VR this
sensor will be added to the system to see how the
other parts will adapt their selves to this new
configuration. If a resource is not be able to
adapt itself to new configuration, there will be
failure in whole system.
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• References

• Brennan, R.W.   Fletcher, M.   Norrie, D.H.  
  Reconfiguring Real-Time Holonic Manufacturing
  Systems, Proceedings of the 12th International
  Workshop on Database and Expert Systems
  Applications, Page 611, 2001.
• Vrba, P.   Marik, V.  , Simulation in
  agent-based manufacturing control systems, 2005
  IEEE International Conference on Systems, Man and
  Cybernetics, page(s) 1718- 1723 Vol. 2, Oct.
  2005.
• Xiaokun Zhang   Norrie, D.H.   Brennan, R.W.  
  Yuefei Xu, A multi-level reconfiguration control
  for holonic PLC , 2000 IEEE International
  Conference on Systems, Man, and Cybernetics,
  page(s) 1762-1767 vol.3, 2000.
• Xiaokun Zhang Sivaram Balasubramanian Robert W.
  Brennan Douglas H. Norrie, Design and
  implementation of a real-time holonic control
  system for manufacturing, Information
  SciencesApplications An International Journal,
  Volume 127 ,  Issue 1-2  (Aug. I 2000).

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• References

• M.Bal, M. Hashemipour, Applications of Virtual
  Reality in Design and Simulation of Holonic
  Manufacturing Systems A Demonstration in
  Die-Casting Industry, Proceedings of the 3rd
  international conference on Industrial
  Applications of Holonic and Multi-Agent Systems
  Holonic and Multi-Agent Systems for
  Manufacturing, Pages 421 432, 2007.
• Rockwell Automation Company, IEC 61499 Function
  Block Model Application Note, www.isagraf.com,
  April 2008.
• James H. Christensen, The IEC 61499
  StandardConcepts and RD Resources,
  http//www.rockwell.comhttp//www.holobloc.com.

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