Reconfigurable concepts and architectures have been used in the research domain for industrial automation and control systems since several years. For example, Kramer et al. have introduced this important topic for distributed systems. In general, the main aim of reconfiguration is related to the altering of functions and algorithms in software models. Especially in the automation domain reconfiguration means the adaptation and adjustment of control functions and algorithms in control, communication, measurement and field devices due to changed requirements. Usually, there are many ways to describe reconfigurability of software elements. This topic can be solved in different ways: reconfigurability can happen on a higher level (e.g., implemented by Multi-Agent Systems) as well as also on a lower level (e.g., real-time control with IEC 61131 or IEC 61499). Moreover, one has to distinguish between static and dynamic reconfiguration –. Especially on the real-time control level, which is in the scope of the approach introduced in this study, there are some concepts mentioned in the literature. Most of the actual PLC systems based on IEC 61131 support some kind of reconfiguration. This means that control programs can be adapted in PLCs but this is carried out in a relative simple way. Normally, the modified PLC program is downloaded to the PLC hardware and the corresponding software system decide the point in time where the “old” program is replaced by the “new” one. Usually there is no way to control the exchange procedure in modern PLC systems. In contrast the IEC 61499 reference model for distributed and reconfigurable IPMCS provide a management model and the corresponding Application Programming Interface (API). Therefore, it provides the possibility to control the life-cycle of software components (i.e., FBs) in distributed control devices. Moreover, IEC 61499 defines eight different configuration commands (i.e., START, STOP, KILL, READ, WRITE, CREATE, DELETE, QUERY) which are often used in the literature to adapt FB instances and therefore control applications. The main difference to the approach in IEC 61131-3 is that the reconfiguration is carried out on a more detailed level without the need to adapt a whole control program. In addition, a standardized management interface is missing in IEC 61131-3 systems and also the event driven architecture of IEC 61499 allows to better synchronizing adaptation steps. According to the literature, the IEC 61499 management interfaces is mainly used for adapting control algorithms –. The topic of using the management interface as basis for the reconfiguration of communication links. Nowadays Modern control engineering concept moving from traditional PLC based centralized control system to Distributed control system. The reason is globalization of market need to make manufacturing industries to rapidly change or customize their production in respond to change in custom need,

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domain, the concept of flexible distributed control system get popular. Modern manufacturing/ production/logistic application need to flexible, fast changing, reconfiguration and reused feature as to respond to fast changing market demand, production variation, technology variation. The high level demanded features need to address by modern control engineering are: Distribution: The ability to distribute software program component among distributed hardware devices Configurability: Any device and its software components can be configured by software tools from multiple vendors. Reconfiguration: The ability to adapt control hardware and software during operation. Interoperability: Embedded devices can operate together to perform the functions needed for distributed applications. Portability: Software tools can accept and correctly interpret software components and system configurations produced by other software tools. The new international standard IEC 61499 introduce model to implement distributed control system with reconfigurability, reused and interoperatibilty features. Therefore this paper focus on distributed and reconfigurability added to process control devices using IEC 61499 function block model structure by distributed function blocks among several devices.

Distributed conceptbring the change into automation into manufacturing and process industries. In distribution phenomena the control can be distributed among the several hierarchical control layer from field to top layer management. The whole application distributed among various layer to fulfil the complete functionality using various communication protocols standards. IEC 61499 enable to design and develop flexible distributed control system/applications by merging the features of PLC function blocks and DCS function blocks. It’s abstract model is basic function block and support the even based execution. The application can be created by interconnection of even driven software modules with distributed application among the various resources. IEC 61499 standard define general model and methodology for describing function blocks in a format that is independent of specific application implementation. This model used by designers to develop distributed control application for industries. Basically application based on this standard allow system in term of logically connected function blocks sharing among various resources. Generalized concept based on IEC 61499 standard is illustrated below figure-1

Device, application and resources are the main elements of distributed process control system based on IEC 61499 model structure. The device is basic control element consist processor, I/O interfacing and communication interfacing. The application is group of function blocks communicating to each other to complete the control tasks. The resource is considered as sub-device which can independent control of its operation and the part of distributed application run on resources. The 61499 standard facilitate the world trade by removing centralized barriers drawback by providing the portability, configurability & reconfigurability and interoperatibilty features. The configurability of device means device can be configurable by control software. The reconfigurability means device can be reconfigurable by change in its parameters or variable from multiple vendors by software tool of multiple suppliers.

reconfigurability at abstract level of Function block of IEC 61499 standard.

PLC and CNC are used as lower level production line automation implementation. Reconfiguration control of these controllers can be great challenge due to different characteristics of individual control rules. Combine them both in single manufacturing environment to achieving reconfigurable control architecture in focus interest. For that initially study reconfigurable control of PLC and CNC controller. Then study the reconfigurable transform rules from PLC and CNC to IEC 61499 – describe transform rules from IEC 61131 to IEC 61499 reference structure model and describe STEP-NC reconfigurable numerical controller. Then implement reconfigurable control for single PLC and CNC based manufacturing industries. This work can focus on reconfiguration need for lower level machine control enable to design IEC 61499 compliant PLC controller of machine. That can be move to transform to new structure and then integrate them into lower level manufacturing network of production line. For that first, mapping IEC 61499 and IEC 61499 elements to physical structure of production unit. second, constructing IEC 61499 complaint PLC controller design by reconfiguration concept.

As shown in fig.- 4 PLC and CNC act as lower level manufacturing controller connected by industrial fieldbus. IEC 61499 compliant architecture proposed based on reconfigurable control software structure from lower level production environment. To do that, PLC and CNC controller are act as DEVICE model and even based control execution mechanism used as reconfiguration triggers and action.

In the domain of PLCs, which are widely used in industrial control applications, the IEC 61131-3 definition for the harmonization of programming languages plays an important role. In this standard no concepts and methods are described for a harmonization of communication concepts and patterns which are seen to be very important in a network of heterogeneous controllers and field devices. Only part 5 of the IEC 61131 standard provide special functions blocks which covers the communication in PLC systems, but up to know they are rarely used in industrial applications. Currently, there is a much more sophisticated development ongoing which has a high potential to harmonize the information and data exchange in PLC-based

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UA Information Model for IEC 61131-3” . Similar to the IEC 61131-5 definitions the IEC 61499 model provides high-level communication patterns and functions for the information exchange between embedded control devices. However, the usage of a special communication protocols (e.g., Ethernet, Industrial Ethernet, field bus) is not in the focus 1Programmable Logic Controller of this high-level specification. Some mappings to domain protocols are documented in the literature.

Reconfigurable concepts and architectures have been used in the research domain for industrial automation and control systems since several years. For example, Kramer et al. have introduced this important topic for distributed systems. In general, the main aim of reconfiguration is related to the altering of functions and algorithms in software models. Especially in the automation domain reconfiguration means the adaptation and adjustment of control functions and algorithms in control, communication, measurement and field devices due to changed requirements. Usually, there are many ways to describe reconfigurability of software elements. This topic can be solved in different ways: reconfigurability can happen on a higher level (e.g., implemented by Multi-Agent Systems) as well as also on a lower level (e.g., real-time control with IEC 61131 or IEC 61499). Moreover, one has to distinguish between static and dynamic reconfiguration. Especially on the real-time control level, which is in the scope of the approach introduced in this paper, there are some concepts mentioned in the literature. Most of the actual PLC systems based on IEC 61131 support some kind of reconfiguration. This means that control programs can be adapted in PLCs but this is carried out in a relative simple way. Normally, the modified PLC program is downloaded to the PLC hardware and the corresponding software system decides the point in time where the “old” program is replaced by the “new” one. Usually there is no way to control the exchange procedure in modern PLC systems. Programming Interface (API). Therefore, it provides the possibility to control the life-cycle of software components (i.e., FBs) in distributed control devices. Moreover, IEC 61499 defines eight different configuration commands (i.e., START, STOP, KILL, READ, WRITE, CREATE, DELETE, QUERY) which are often used in the literature to adapt FB instances and therefore control applications –. The main difference to the approach in IEC 61131-3 is that the reconfiguration is carried out on a more detailed level without the need to adapt a whole control program. In addition, a standardized management interface is missing in IEC 61131-3 systems and also the event driven architecture of IEC 61499 allows to better synchronizing adaptation steps. According to the literature, the IEC 61499 management interface is mainly used for adapting control algorithms. The topic of using the management interface as basis for the reconfiguration of communication links is only briefly discussed in a few papers. Summarizing, the IEC 61499 approach provides a very good baseline for reconfigurable control systems in a distributed environment but a more formalized approach for defining reconfigurable gateway functions in order to dynamically adapt communication links is currently missing.

PROGRAMMABLE LOGIC CONTROLLERS

If the communication in the small applications is not critical than is sufficient to control these by one programmable logical controller (PLC). The role of the communication is exchanging of connection with a common computer in order to create and transmit the program to PLC and to transmit data to superior levels for operator’s control of technology. At the direct control it is possible to rely on the response specified by manufactures between input change and adequate reaction (A-A´, Fig. 5). This response ranges about 10 ms depending on memory size, processor speed or on the longest time of programming repetition cycle (scan time). While building distribution control system for controlling large industrial application it is very important to solve the question of communication. Sometimes there arises the question about controlling output on the remote PLC, which is available only via industrial communication network (B-B´, Fig. 5). In this case the response will be bigger and depend on a lot of factors. Industrial networks cover mainly production control, so it is very important to ensure high reliability, deterministic mode of communication and high power. On the other hand industrial networks enable connection (C-C´, Fig. 5) with centralized operator layer (PC with function

Common corporation (proprietary) industrial networks use only three layers from standard reference communication model (RM-OSI) – physical, link and application layer. See comparison in the Tab. 1. Modern networks based on industrial Ethernet and TCP/IP technologies use five layers, where network layer and transport layer are allocated to physical and link layers to support TCP/IP technology.

Managing connections between remote PLC performs the data link layer with use.

By the practical example one form of data communication among more PLCs was demonstrated. We chose the model where both processors were the SIMATIC type. We chose the Industrial Ethernet network with service S7 communication. For data transfer we used system blocks SFB 12 BSEND and SFB 13 BRCV, which are able to transfer maximum data capacity 32 kB for S7 – 300 and 64 kB for S7-400. As it has been mentioned and experimentally verified, the data communication speed among several PLCs mainly depends on used hardware (CPU type), industrial network used for data transfer and parameter settings of system blocks including the size of transferred data. The knowledge, need of IEC 61499 reference standards for developing flexible distributed system is fully describe. FBDK is most popular academic/research oriented software tool to develop and stimulate/test distributed application based on IEC 61499 reference model. Function block is basic element of IEC 61499 provide even based execution mechanism, reconfiguration at algorithm level, easily in IEC 61499 reference model. Reconfigurable phenomena study at various aspect :1.Algorithm level of function block 2. Modular structure of application and 3. Transformation from PLC,CNC controller to IEC 61499 model structure.

• Alois ZOITL1 Gunnar GRABMAIR2,Franz AUINGER3 and Christoph SUNDER4 ,―Executing real-time constrained Control Applications modeled in IEC 61499 with respect to Dynamic Reconfiguration pp 62-67,IEEE 2005.

• FRANEKOVÁ, M.; KÁLLAY, F.; PENIAK, P.; VESTENICKÝ, P. Komunikačná bezpečnosť priemyselných sietí. Žilina 2007. ISBN 9078-80-8070-715-6.

• IEC 61131: Programmable controllers, Part 3: Programming languages, International Electrotechnical Commission Std. IEC 61 131, 2003. [Online]. Available: www.iec.ch

• J. J. Scarlett and R. W. Brennan, “Evaluating a new communication protocol for real-time distributed control,” Robotics and Computer- Integrated Manufacturing, vol. 27, no. 3, pp. 627–635, 2011.

• M. Fletcher and D. Norrie, “Realtime reconfiguration using an IEC 61499 operating system,” in Parallel and Distributed Processing Symposium., Proceedings 15th International, Apr. 2001, pp. 985–991.

• M. Khalgui, O. Mosbahi, Z. Li, and H.-M. Hanisch, “Reconfiguration of Distributed Embedded-Control Systems,” Mechatronics, IEEE/ASME Transactions on, vol. 16, no. 4, pp. 684–694, Aug. 2011.

• M. Sadeghi ―Developing IEC61499 in Industrial Processes, Measurement and Control Systems (IPMCS), vol 5 issue 4,pp 238-241, wseas transaction on systems and control,2010.

• M. Sadeghi ―Developing IEC61499 in Industrial Processes, Measurement and Control Systems (IPMCS)‖, vol 5 issue 4,pp 238 241, wseas transaction on systems and control,2010.

 M. Trejo-Herbabdez,E. Lopez-Mellado ―Specification of Manufacuring Systems

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• M. Vall´ee, M. Merdan, W. Lepuschitz, and G. Koppensteiner, “Decentralized Reconfiguration of a Flexible Transportation System,” Industrial Informatics, IEEE Transactions on, vol. 7, no. 3, Aug. 2011.

• R. Brennan, M. Fletcher, and D. Norrie, “An agent-based approach to reconfiguration of real-time distributed control systems,” Robotics and Automation, IEEE Transactions on, vol. 18, no. 4, pp. 444–451, Aug. 2002.

 T. Strasser, C. Sunder, A. Zoitl, M. Rooker, and J. Brunnenkreef, “Enhanced IEC 61499 Device Management Execution and Usage for Downtimeless Reconfiguration,” in Industrial Informatics, 2007 5th IEEE International Conference on, vol. 2, June 2007, pp. 1163–1168.