Abstract: This paper discusses the impact of network architecture on control performance in a class of distributed control systems called networked control systems (NCSs) and provides design considerations related to control quality of performance as well as network quality of service. The integrated network-control system changes the characteristics of time delays between application devices. This study first identifies several key components of the time delay through an analysis of network protocols and control dynamics. The analysis of network and control parameters is used to determine an acceptable working range of sampling periods in an NCS. A network-control simulator and an experimental networked a machine tool have been developed to help validate and demonstrate the performance analysis results and identify the special performance characteristics in an NCS. These performance characteristics are useful guidelines for choosing the network and control parameters when designing an NCS.

Abstract: Describes a new framework for distributed control systems in which estimators are used at each node to estimate the values of the outputs at the other nodes. The estimated values are then used to compute the control algorithms at each node. When the estimated value deviates from the true value by more than a pre-specified tolerance, the actual value is broadcast to the rest of the system; all of the estimators are then updated to the current value. By using the estimated values instead of true value at every node, a significant saving in the required bandwidth is achieved, allowing large-scale distributed control systems to be implemented effectively. The stability, performance, and expected communication frequency of the reduced communication system are analyzed in detail. Simulation and experimental results validating the effectiveness and communication savings of the framework are also presented.

Abstract: Bluetooth is a method for data communication that uses short-range radio links to replace cables between computers and their connected units. Industry-wide Bluetooth promises very substantial benefits for wireless network operators, end workers, and content developers of exciting new applications. This article delves into the implementation and architecture of Bluetooth. It also describes the functional overview and applications of Bluetooth, and deals with the development of a model for recording, printing, monitoring, and controlling of eight process variables at the same time, using a distributed control system. We explain industrial automation via Bluetooth using IISS. Industrial automation is one of the major applications of Bluetooth technology. Industrial automation, in terms of controlling or monitoring a factory, office, or industrial process, means to install machines that can do the work instead of human workers. Industrial plants consists of many devices interconnected in different ways ranging from simple data collection units (I/O) to more intelligent devices such as sensors, one-loop controllers, or programmable controllers, and a supervisory system used as a human-machine interface (HMI) for data logging and supervisory control. An IISS is a controlling device that monitors the devices in a company. It basically communicates via the interface card in the PC; the hardware is connected parallel across the device, and it is interfaced with the PC via a transceiver. The device can be accessed both manually via the switches and remotely via the PC. A simulation of connecting a PC with the machines in a company was executed. Also, we wrote a software program using C language; we will show how the remote monitoring takes place between the control room and the PC. These details in the article establish the growing need for Bluetooth technology.

Abstract: A plant (72) is operable to receive control inputs c(t) and provide an output y(t). The plant (72) has associated therewith state variables s(t) that are not variable. A control network (74) is provided that accurately models the plant (72). The output of the control network (74) provides a predicted output which is combined with a desired output to generate an error. This error is back propagated through an inverse control network (76), which is the inverse of the control network (74) to generate a control error signal that is input to a distributed control system (73) to vary the control inputs to the plant (72) in order to change the output y(t) to meet the desired output. The control network (74) is comprised of a first network NET 1 that is operable to store a representation of the dependency of the control variables on the state variables. The predicted result is subtracted from the actual state variable input and stored as a residual in a residual layer (102). The output of the residual layer (102) is input to a hidden layer (108) which also receives the control inputs to generate a predicted output in an output layer (106). During back propagation of error, the residual values in the residual layer (102) are latched and only the control inputs allowed to vary.

Abstract: A distributed control system is provided where the controllers are split into two dissimilar groups and flight control responsibility is further allocated within each group such that one entire group plus one further controller can fail without compromising the pilot's ability to fly the aircraft.

Abstract: Today's control applications are either based on traditional distributed control systems or on programmable logic controllers. They are usually composed of monolithic applications that are almost impossible to integrate and even to expand. Even more, the many different types of commercial fieldbuses resulted in a wide diversity of devices and tools to support the development of Industrial Process Measurement and Control Systems (IPMCSs). The demand for integration, both during the development phase as well as during the operational phase is becoming more than evident. In this paper, we present CORFU, an OO framework to improve the engineering process of JPMCSs in terms of reliability, development time and degree of automation. The defined framework embodies an abstract design that is capable to provide solutions for the family of distributed JPMCSs.

Abstract: High wind penetration hybrid wind-diesel systems have complex control requirements. The random nature of the wind, the cubic velocity to power relationship and the fast response of wind turbines make control goals like maintain system stability, and prescribed power quality levels, not easy to achieve. This paper deals with how to implement a distributed control system based on the controller area network (CAN) in hybrid wind diesel systems with high wind penetration. Firstly some introduction to hybrid wind-diesel systems is presented. Secondly two architectures for such hybrid systems are presented and studied mainly from the control point of view. This study concludes with a need of a distributed control, and the definition of some sensor and actuator nodes in the system. The CAN bus is used to close one of the several regulation loops presented. Some considerations about real time distributed control like clock synchronization among nodes when using CAN bus are presented. Finally some advantages of using CAN with such hybrid systems are outlined.

Abstract: In this paper we describe a general approach for dynamic and intelligent reconfiguration of real-time distributed control systems that utilises the IEC 61499 function block model. This work is central to the development of distributed intelligent control systems that are inherently adaptable and dynamically re-configurable. The approach that is used takes advantage of distributed artificial intelligence at the planning and control levels to achieve significantly shorter up-front commissioning times as well as significantly more responsiveness to change. This approach is based on object-oriented and agent-based methods and aims at overcoming the difficulties associated with managing real-time reconfiguration of a holonic manufacturing system.

Abstract: This chapter discusses the details of Controller Area Network (CAN). The CAN is a serial bus system that was developed to support distributed control systems in automobiles, and has also been implemented widely in industrial control systems as well. It is a popular network for communicating between sensors and controllers in automotive and industrial applications. Some of the details in the CAN specification and getting one started using TINI as both a CAN controller and a CAN sensor interface are provided. Furthermore, it shows how to configure TINI to talk and listen to CAN data frames, and implement a CAN sensor device and a CAN actuator.

Abstract: A control and data processing system for HT-7, the first super-conducting tokamak in China, is developed in order to both control the experimental system and process the huge amount of experimental data (600 MB/shot). A fully distributed structure is adopted. The distributed control system (DCS) includes several subsystems, such as those for the main control, synchronization, safety, interlock, data acquisition and data analysis, physical data management, remote control facility via networks, etc., The basic element of the DCS is the personal computer (PC) with a Fiber Distributed Data Interface based on a fast network. The system uses multiple data-transfer paths in parallel and categorizes the entire computer functions into the servers. The subsystems for main control, communication, and data management are described in detail.

Abstract: According to the Freedonia group, OEM demand for automotive electronics is predicted to grow from $20.5B in 1999 to $37B in 2009 corresponding to an increase in electronics per vehicle of $1,208 in 1999 to $1,864 in 2009. New or enhanced automotive systems include intelligent airbags, adaptive cruise control, steer-by-wire, brake-by-wire, electronic stability control, telematics, and passenger entertainment systems. To meet the higher vehicle power requirements for these and other systems the industry is moving to a 42V system. A 42V system will also enable combined starter/alternators and electronic valves. With the switch from hydraulic or mechanical to electronic actuation, distributed control systems with smart actuators are being developed. Placing the electronics at the point of use often exposes the electronics to temperatures well above the conventional 125°C limit. Under-hood temperatures are approaching 140°C, on-engine and in-transmission temperatures are 150-175°C and wheel mounded temperatures are 250°C. This paper will examine the system level motivation for distributed systems and the resulting temperature requirements. The temperature limitations of semiconductor and passive components, and packaging and interconnection technology will then be discussed. An in-transmission control module developed for 150-165°C use will be discussed in detail to identify the unique challenges of high temperature electronics.

Abstract: Known control systems utilised in zoned heating systems take one of two forms, these being centralised or distributed control systems. The former suffers from problems, eg the need for high reliability connections. The latter also suffers from problems, eg reduction in boiler efficiency and impact of loss of control signal. The invention therefore provides a temperature control system (10) comprising a plurality of output controllers (16,18), and means for providing a synchronisation signal to provide a common start reference for output cyclers of the output controllers (16,18) so as to allow a respective temperature control device (20,22) to be activated or deactivated by one of the controllers (16,18).

Abstract: A semiconductor workpiece processing tool includes process modules having a robot loading window and a manual loading window, and a control system for managing a production route defining movement of the workpiece among a number of the process modules. The control system includes a user interface through which an operator can define the production route and recipes to be performed on the workpiece in each of the process modules, a system controller for controlling execution of the production route, a process module controller associated with each of the process modules for controlling the processing of the workpiece in the process module, and a network connecting the control system components. Advantages of the invention include the ability to continue a production route while manually operating a process module. As a result, the tool may continue in operation while selected process module are tested, maintained or otherwise used to process workpieces.

Abstract: This paper presents a set of rationalesa behind applying so called holonic manufacturing principles as a technological solution to the growing business concerns in chemical process industries. The anticipated benefits from holonic approach stem from the use of a distributed control systems architecture that supports flexible unit operations to dynamically integrate and collaborate with others as and when the production conditions change. A requirements deployment process is used to relate the business pressures in CPI to a set of systems requirements within key areas of Process engineering and Process control. By creating a vision of a holonic process plant, it is next illustrated how a holonic approach might eliminate limitations of the conventional top-down methodology of designing process control systems through a radical, bottom up approach to the structuring and operation of the process plants.

Abstract: The development and implementation of an agent-based distributed control system in a wastewater treatment plant (WWTP) are shown. The hardware architecture contains different supervision levels, including two autonomous process computers, a programmable logic controller (PLC) and a knowledge-based system (KBS), acting at the top supervisory level. The knowledge is organized in several distributed agents, representing the available knowledge for every subprocess of the WWTP. In addition to these independent agents, a supervisor agent acts as its master. The distributed multi-agent architecture improves previous developments with monolithic KBS, allowing the development of independent and reusable agents. Different strategies have been included, adapted, and modified without a great programming effort. The developed system has involved the transformation of a classical control system into a system that enables a WWTP to respond to different usual problems. Finally, the system has been satisfactorily validated supervising a pilot WWTP for more than 3 years.

Abstract: This paper describes a framework of Internet-based distributed control system and the design and implementation of its software in a multiple server/client environment. Main issues addressed in this paper are the infrastructure of the system, the functionalities of components, and real-time scheduling behaviors of the software. Both event and time triggered real-time scheduling has been adopted. Built-in dependability technologies are adopted to ensure customized applications can be integrated into the distributed system easily. The programmable and re-configurable framework of the system provides a flexible mechanism for constructing distributed real-time applications. A language neutral interface is used for communication and data access between distributed nodes. Connectivity and controllability of virtual Web devices and their interoperability are described. Because of the importance of timeliness and dynamics in real-time systems, emphases have been put on time and event scheduling for Web-based distributed systems.

Abstract: In the design of fault tolerant real time systems, the most important issue is fault handling and redundancy managing. Adding hardware as well as software in order to tolerate faults requires a redundancy strategy to attain and prove the expected as well as the required fault tolerance. This paper presents fault handling strategies of a future distributed architecture for a flight control system (FCS) designed for the JAS 39 Gripen, a modern 4th generation multi-purpose combat aircraft. The results are based on knowledge of and experience from the JAS 39 Gripen, with over 15000 flight hours. Consequently, a highly dependable real time control system is addressed, however, the principles of the distributed system are general and can be applied to other combat and commercial aircraft as well as for other embedded control systems, e.g. in cars, trains etc. The distributed architecture aims to tolerate permanent and transient physical faults, whereas software design faults are not catered for. Simulations give experimental results for validation of the fault tolerance qualities of the distributed control system. The fault handling simulations include transient fault recovery, exploring three redundancy principles and also tests of time limits for permanent fault handling, i.e. system reconfiguration. The results are based on experiments on a simulator validated against the actual aircraft.

Abstract: An important process control trend is the implementation of digital communication with field control devices. Traditional distributed control systems are being augmented with smart field instruments. Foundation Fieldbus is a digital control network that interlinks such "smart" field instruments like sensors and actuators in a process control environment. In the Foundation Fieldbus all the control algorithms and data acquisition are executed by structures called function blocks. This paper attempts to improve the performance based on these function blocks. First, an introduction to the function blocks of Foundation Fieldbus and their structure and execution process are presented. Then, an example of a fermentation process is described. The structure of the control system and the implementation of distributed control based on function blocks are discussed. Finally, the problems related to system safety with function blocks and their programming language are dealt with.

Abstract: Nowadays distributed systems have demonstrated to be one of the best options for the industrial control systems implementation due their flexibility and power, which are increased with the application of artificial intelligence techniques In this line, our group has developed several distributed systems applied to chemical analysis and industrial automation For these implementations a CAN network was used This article proposes a new layered architecture for the implementation of these intelligent and distributed systems In that line, several techniques of discrete control may be used, from Petri nets to an expert system based on rule nets, while continuous control loops may be implemented by means of from traditional PID devices to distributed neural network approaches Finally, for the communication layer implementation an industrial network such as CAN or TTP among others, will be used This architecture defines the services offered by each layer, and specifies the interface between any two adjacent layers It also defines the required characteristics of the protocols at any layers, and the capabilities that should be implemented Finally, an implementation example of this architecture is presented

Abstract: This paper deals with the distributed Controller Area Network (CAN) based control system design for experimental Autonomous Locomotion Robot (ALR) VUTBOT-2. It also features a System of Aviation Modules (SAM) description for airborne applications. Distributed control system of the ALR is generated by microprocessor units, which are linked by the CAN. As a Higher Layer Protocol (HLP) the CANAerospace protocol was chosen. CANAerospace is an extremely lightweight protocol/data format definition, which was designed for highly reliable communication with microprocessor-based systems in airborne applications via CAN. It is successfully implemented with the SAM.

Abstract: We discuss the application of programmable logic controllers (PLCs) in the process monitoring and control for fuel alcohol production. The PLCs are mainly utilized for collecting process data as well as realizing auto-tuning PID and sequence control strategies. In addition, WinCC configuration software with a human-machine interface (HMI) is used to monitor the dynamical industrial process. Both software- and hardware-based implementations of our system are also described in detail.

Abstract: Inductive heating applications, such as pipe welding or steel-tape annealing, require electrical power ratings of several MWs at frequencies up to 100 kHz and higher. To realize this high power frequency product, several inverters or several power semiconductor devices have to be connected in parallel, because the maximum rating of a single inverter unit is often far below the required rated power. In this paper, a control strategy for parallel connected soft-switching (ZVS and near ZCS) high-frequency voltage-source IGBT- or MOSFET-inverters is presented. The proposed distributed control system, where one control unit is dedicated to each inverter, ensures synchronous switching without any communication between individual control units. Distinctive features include high reliability, flexible configurations, reduction of long communication lines and good monitoring properties.

Abstract: The current development of communication technology makes it possible for control engineers to implement networked architectures for distributed control systems. However, the data transfer over communication networks inevitably adds some non-deterministic delays in the closed-loop systems. The analysis and design of this type of systems has attracted a great deal of research interest over the world. In this paper, a laboratory system is used to study the issue of non-deterministic delays in a networked control system. The study is based on a physical platform where three computers, functioned as a digital model of a plant, a system identifier and a learning controller respectively, are communicated through an Ethernet. In this system, identification and learning control are based on Gaussian-function neural network algorithms. Some network-induced delay in our three-computer-Ethernet platform is measured and its effect on the control system is analysed. To reduce the detrimental effect caused by the delays, a scheduling approach, tested on our laboratory system with favourable results, is presented in this paper. Due to its simplicity and effectiveness, it is believed that it may be possible to apply the proposed approach to some practical networked control systems.

Abstract: A multifunction machine, such as a PCB manufacturing platform, has a plurality of task-specific modules each configured to perform a dedicated task. The machine includes a service interface providing to each of the plurality of task-specific modules a common supply, including power and a communications system backbone. A distributed control system is realized by the communication system backbone associated with the machine and task-specific modules. The task specific drivers co-operate, in use, with the communication system backbone to allow controlled operation of the specified task supported by its respective task-specific module. Through the use of a modular approach, the assembly process can be consolidated into a relatively small physical area of a factory or plant room, with commonly shared equipment further simplifying overall system control and programming.

Abstract: This paper presents the results of an academia-industry collaborative project whose main objective was to test novel techniques for the development of event-driven control systems in the batch processing (e.g., pharmaceutical, fine chemicals, food) industries. Proposed techniques build upon industrial standards and focus on (i) formal synthesis of phase control logic and its automatic translation into procedural code, and (ii) verification of the complete discrete-event control system via dynamic simulation. In order to test the techniques in an engineering environment, a complete discrete-event control system was produced for a benchmark batch process plant based on a standard development method employed by one of the industrial partners. The control system includes functional process specification, control architecture, distributed control system (DCS) proprietary programming code for procedural control at equipment, unit, and process cell levels, and human-machine interfaces: A technical assessment of the development method and the obtained control system was then carried out. Improvements were suggested using the proposed techniques in the specification, code generation and, verification steps. The project assessed the impact of these techniques from both an engineering and economic point of view. Results suggest that the introduction of computer aided engineering (CAE) practices based on the benchmarked techniques and a structured approach could effect a 75% reduction of errors produced in the development process. This translates into estimated overall savings of 7% for green-field projects. Figures were compared with other partners' experience. It is expected that the work load on a given project will shift, increasing the load on process engineers during the specification stage and decreasing the load on the software engineers during the code writing.