• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 36
  • 14
  • 2
  • 1
  • Tagged with
  • 53
  • 37
  • 37
  • 36
  • 35
  • 26
  • 19
  • 18
  • 15
  • 12
  • 11
  • 11
  • 8
  • 8
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Design and Implementation of a simulator in support of WirelessHART-based control systems development

Shah, Kunjesh January 2009 (has links)
In Industrial automated process plants, the wired communication system is being replacing by the newly developed wireless communication system as it is easy to use, scalable, simple, reliable, and provide more flexibility for installing and operating process automation equipments. The WirelessHART network is becoming popular for wireless communication system in industrial automation plant system. However this network works on the TDMA bus arbitration technique. Each network device needs to be scheduled by the user (network operator) to allow the communications between the field devices and a gateway. Some companies like DUST have already manufactured the device hardware to implement this wireless communication system on industrial automation plant. A Simulator of this system is necessary to imitate the system performance on computer using the computer programming to simulate the result of each timeslot. Purpose of designing this simulator is to use the timeslots more efficiently and to offer collision free communications between network devices. It is may be time taking process to build the simulator in the beginning but at the end it provides cost and time effective solutions.  This report describes how the simulator has been designed for the system at various phases e.g. architecture, design, and implementation etc.
2

DESIGN AND IMPLEMENTATION OF WIRELESSHART TDMA STATE MACHINE

Kannah, Ali, Bahiya, Ghasaq January 2011 (has links)
WirelessHART is one of the latest communication standards that have enhanced functionality and robustness. The standard is ideal for applications in control and automation industry. In this work we present an implementation the TDMA state machine of the WirelessHART communication protocol on TinyOS operating system using the nesC language for the Telobs motes. The development was carried out using software reuse principle and involved comparing the state diagram description of the TDMA presented in WirelessHART with that of the time synchronized frequency hopping implementation that was already available for reuse. The work highlights the differences between the TSCH code and the WirelessHART specifications and builds upon the TSCH code to arrive at the WirelessHART TDMA state machine implementation.
3

Design and Implementation of a simulator in support of WirelessHART-based control systems development

Shah, Kunjesh January 2009 (has links)
<p>In Industrial automated process plants, the wired communication system is being replacing by the newly developed wireless communication system as it is easy to use, scalable, simple, reliable, and provide more flexibility for installing and operating process automation equipments. The <strong>WirelessHART</strong> network is becoming popular for wireless communication system in industrial automation plant system. However this network works on the TDMA bus arbitration technique. Each network device needs to be scheduled by the user (network operator) to allow the communications between the field devices and a gateway. Some companies like DUST have already manufactured the device hardware to implement this wireless communication system on industrial automation plant. A Simulator of this system is necessary to imitate the system performance on computer using the computer programming to simulate the result of each timeslot. Purpose of designing this simulator is to use the timeslots more efficiently and to offer collision free communications between network devices. It is may be time taking process to build the simulator in the beginning but at the end it provides cost and time effective solutions. </p><p>This report describes how the simulator has been designed for the system at various phases e.g. architecture, design, and implementation etc.</p>
4

Využití bezdrátového měření teploty pro řízení rotační pece / The use of wireless temperature measurement to control the rotary kiln

Bednár, Anton January 2013 (has links)
This project tries to find out the possible solution for temperature measurement and control on the rotary calcinations kiln at PRECHEZA company, by using of new wirelessHART temperature transmitters.
5

Implementation of the WirelessHART MAC Layer in the OPNET Simulator

Yipeng, Wang January 2013 (has links)
Industrial wireless sensor network (IWSN) is an application area of WSN used in industrial process monitoring and control with strict time and reliability requirement. WirelessHART standard is the first international standard for IWSN approved by International Electrotechnical Commission (IEC). This is worthwhile to implement this standard on simulator platform. Based on the study of WirelessHART standard, this thesis set up a primary implementation of the MAC layer of WirelessHART standard. To our best knowledge, this is the first comprehensive implementation of WirelessHART using OPNET simulator. The implementation has been evaluated rational. And some improvement of current implementation and standard have also been proposed and implemented. Flexible dedicated slot assignment has also been proposed to reduce the packet loss rate caused by influences of the physical channel.
6

Analysis of reliability and energy consumption in industrial wireless sensor networks

Ersvik, Johan January 2012 (has links)
Wireless sensor networks have attracted the interest of the process industry. A process plant typically contains thousands of devices, monitoring or controlling the process. Today, all these devices are usually connected with wires. Using wireless technology simplifies deployment of new devices in a network and eliminates the need for extensive wiring. But wireless communication is also more sensitive than its wired counterpart. Therefore work is needed to make wireless sensor networks a viable option in many applications. Important issues are, for example, robustness, energy efficiency, and latency. One of the leading communication protocols for industrial wireless sensor networks is the WirelessHART protocol. This thesis investigates three ways of improving performance of the protocol, in terms of reliability and energy requirements. First, the structure of a WirelessHART packet is studied and the removal of certain fields is suggested to make the communication overhead smaller. Second, forward error correcting codes are evaluated using simulations in MATLAB. Third, measurement experiments in actual industrial environments are conducted where radio signals are transmitted and received. The variability of the received signal strength is measured and the effect that polarization diversity has on the signal variability is analyzed. The findings indicate that substantial improvements can be attained by employing polarization diversity, which can reduce channel variability and increase the expected signal strength significantly. The improvements in channel gain can be on the order of several tens of dB. The evaluations of forward error correcting codes show that the reliability is improved, with a channel gain of 3 dB. The study of the WirelessHART packet structure indicate that the packet sizes can be reduced by 15%. In turn, this also reduces energy requirements and packet error rates by 15%. This is equivalent to a gain in SNR on the order of a tenth of a dB.
7

Comparative study of wireless protocols : wi-fi, bluetooth, ZigBee, WirelessHART and ISA SP100, and their effectiveness in industrial automation

Abdul Ghayum, Mohamed Shahid 14 February 2011 (has links)
A decade ago, wireless technology was unimaginable in its application in industrial automation as wireless had poor reliability and security in the form of time delays and frame losses. Also, lack of interoperability and standards has been a barrier for wireless applications in control system. But with recent advancements in wireless technology, and with the underlying advantages of wireless like low infrastructural costs, scalability, mobility, and ability to operate in extreme and remote environments, many are seriously considering wireless for industrial automation solutions. For wireless implementation in industries, it is important to understand its characteristics - security, update rates, data types, protocols, and latency time. Protocol being an important characteristic of any communication, is to be chosen intelligently for maximum efficiency. Because of the complexity of creating a communication protocol, existing information technology (IT) protocols such as Wi-Fi, Bluetooth, and ZigBee were used in industries. But as applications widened, and interoperability became an important factor to be considered, it was required to standardize the protocols used. ISA SP100 and WirelessHART are results of this standardizing process. For the last few years, there has been a huge discussion on which of these protocols are robust and work better, and none has emerged as clear winners. The aim of this thesis is to explore the capabilities and limitations of each of these protocols for various industrial applications. This thesis considers all these protocols and helps choose the best fit for industrial applications and includes study of security, reliability, and efficiency of these protocols. / text
8

Avaliação de Desempenho de uma Rede WirelessHART

Fraga, David John Freitas 08 September 2014 (has links)
Submitted by Lucelia Lucena (lucelia.lucena@ufpe.br) on 2015-03-06T19:14:40Z No. of bitstreams: 2 DISSERTAÇÃO David John Freitas Fraga.pdf: 2916605 bytes, checksum: e406ab0a5e4df8243c836c3e46fc3925 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) / Made available in DSpace on 2015-03-06T19:14:40Z (GMT). No. of bitstreams: 2 DISSERTAÇÃO David John Freitas Fraga.pdf: 2916605 bytes, checksum: e406ab0a5e4df8243c836c3e46fc3925 (MD5) license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Previous issue date: 2014-09-08 / As redes de sensores sem fio estão sendo cada vez mais utilizadas em várias áreas, dentre elas comerciais, industriais e ambientais. A maior capacidade de processamento e o baixo custo dos dispositivos tornam essa área mais difundida. Em ambientes industriais deve-se levar em conta o contexto em que essa rede será aplicada. Várias instituições investem na produção de novas especificações que atendam esses requisitos, dentre elas a HFC (HART Communication Foundation) que especifica o padrão WirelessHART. Com a popularização desse padrão se tornam necessários trabalhos que avaliem o desempenho dessas redes, através de estudos de caso e cenários onde seja avaliado o seu comportamento com e sem interferência e em diferentes configurações. Essa dissertação apresenta uma rede WirelessHART, avaliando o seu comportamento, em um experimento prático, desde a sua formação até a indução de interferência Wi-Fi e algumas configurações que possam melhorar ou prejudicar o desempenho dessa rede. A experimentação nos mostra o quanto a rede WirelessHART pode ser robusta e que algumas limitações deverão ser consideradas na sua utilização.
9

Design and Implementation of a Network Manager for Industrial Automation Application in WirelessHART Networks

Shahid, Ayaz January 2014 (has links)
Wireless technology has been advancing a lot over the years and it has become mature enough to be used in industrial process control. Wireless sensor networks have overtaken the wired devices and are vastly adapted across the industry. Using wireless technologies in industrial process control results in easy installation and configuration of network and helps in reduction of overall cost. Applying wireless technologies has greater benefits but on the other hand it provides challenges due to harsh industrial environments. Nowadays, wireless sensor devices are smart enough to detect the problems within the network and are capable of producing health reports. To use the capabilities of these smart devices a centralized management is required.  A centralized network manager can manage these smart devices to improve the overall network. Network manager plays a pivotal role because it is a central part of the network and a bad network manager results in network performance degradation. This thesis work addresses the need of centralized network management and proposes a design for the network manager based on the WirelessHART standard. Several algorithms are developed based on the layered architecture of WirelessHART  and a user-friendly graphical user interface is designed for the network manager which is capable of displaying real-time performance and statistics of the network, adding and configuring the nodes, creating routes for the nodes, showing routing tables and neighbour tables and display the network topology. Any change in the network is reflected and displayed by the GUI at run time. The designed network manager is implemented and tested using both simulated packets and real hardware and the work is evaluated using Average Packet Delivery Ratio, Average End to End Delay and by comparing the work to already designed network managers.
10

Stochastic Estimation and Control over WirelessHART Networks: Theory and Implementation

Pesonen, Joonas January 2010 (has links)
There is currently a high interest of replacing traditional wired networks with wireless technology. Wireless communications can provide several advantages for process industries with aspect to exibility, maintenance and installation. The WirelessHART protocol provides a standardized wireless technology for large automation networks that explore wireless communication. However, wireless networks introduce time delays and losses in the communication system, which denes requirements for designing estimators and controllers that can tolerate and compensate for the losses and delays. This thesis consists of several contributions. First, we develop tools for analyzing the delay and loss probabilities in WirelessHART networks with unreliable transmission links. For given network topology, routing and transmission schedule the developed tools can be used to determine the latency distributions of individual packets and quantify that a packet will arrive within a prescribed deadline. Secondly, we consider estimation and control when sensor and control messages are sent over WirelessHART networks. The network losses and latencies are modelled and compensated for by timevarying Kalman lters and LQG controllers. Both optimal controllers, of high implementation complexity, and simple suboptimal schemes are considered. The control strategies are evaluated on a simulation model of a flotation process in a Boliden mine where the wired sensors of the existent solution are replaced by a WirelessHART network scheduled for time-optimal data collection. Finally, we implement a WirelessHART-compliant sensor on a Tmote sky device and perform real experiments of wireless control on a water tank process.

Page generated in 0.0461 seconds