30 research outputs found
Industrial multimedia put into practice
Recent developments in the factory floor technologies together with the widespread use of TCP/IP and
the Internet are increasing the eagerness to support a new wide class of devices and applications, such as
industrial multimedia applications, in factory floor networks. This paper presents how this new field of
applications can be put into practice, via a manufacturing cell field trial being implemented. This
manufacturing automation field trial involves the use of traditional distributed computer control systems
and 'factory-floor-oriented' multimedia (e.g. voice, video) application services
Supporting internet protocols in master-slave fieldbus networks
In this paper we describe how to integrate Internet Protocols (IP) into a typical hierarchical master-slave fieldbus network, supporting a logical ring token passing mechanism between master stations. The integration of the TCP/IP protocols in the fieldbus protocol rises a number of issues that must be addressed properly. In this paper we particularly address the issues related to the conveyance of IP fragments in fieldbus frames (fragmentation/de-fragmentation) and on how to support the symmetry inherent to the TCP/IP protocols in fieldbus slaves, which lack communication initiative
Position paper on time and event-triggered communication services in the context of e-manufacturing
Modern factories are complex systems where
advances in networking and information technologies are
opening new ways towards higher efficiency. Such move
is being driven by market rules with ever-increasing
competition levels, in search for faster time-to-market,
improved process yield, non-stop operations, flexible
manufacturing and tighter supply-chain coupling. All
these aims present a common requirement, i.e. a realtime
flow of information, from the plant-floor up to the
management, maintenance, suppliers and clients, to
support accurate monitoring and control of the factory.
This stresses the importance achieved by the communication
infrastructure in modern manufacturing industry.
This paper presents the authors view concerning the
current trends in modern factory communication systems.
It addresses the problems of seamlessly integrating
different information flows with diverse requirements,
mainly in terms of timeliness. In this aspect, the debate
between event-triggered and time-triggered communication
is revisited as well as the joint support for both types
of traffic. Finally, a view of where factory communication
systems are moving to is also presented, showing the
impact of open and widely available technologies.FCT. Comissão Europeia(ARTIST,IST-2001-34820
A framework for dependability evaluation of PROFIBUS networks
Fieldbus networks have been assuming a high
acceptance in the industrial environment, replacing the old centralized control architectures. Due to time critical nature
of the tasks involved in these environments, the fulfillment of dependability attributes is usually required. Therefore the dependability is an important parameter on system design, which should be evaluated.
Several factors can affect system dependability. The environmental ones are the most common and due to the particularity
of the industrial environment this susceptibility is increased. In this paper it is proposed a framework based on fault injection techniques, supported by a hardware platform which emulates a fault set, representative of industrial environment
scenarios, intending to disturb data communications on a PROFIBUS network. From these fault injection experiments, relevant data is gathered and a further analysis is carried out to evaluate dependability attributes
A comparison of the communication impact in CAN and TTP/C networks when supporting steer-by-wire systems
Distributed real time system is a technology that is become widely used in diverse areas of application, including systems in vehicles, aircraft, locomotives, among others. Great part of these applications is considered critic. Hereupon, such systems must be predictable in relation to its logical result and its temporal behavior, same in operating under failure having to provide tolerances. Distributed real time system requires the use of deterministic and reliable communications mechanisms. A high trend in the automotive area is the replacing of great part of the mechanical andlor hydraulic systems for electronic systems, so called control-by-wire. To reach the objectives of the control-by-wire systems, it is necessary the use of distributed real time systems with fault tolerant properties. This work presents a study about the communication requirements in x-by-wire systems. A theoretic content and a detailed study of temporal property of the CAN and TTP/C network communication are presented in the environment of simulation of the x-by-wire system
Industrial multimedia over factory-floor networks
In this paper we describe a real-time industrial communication network able to support both controlrelated
and multimedia traffic. The industrial communication network is based on the PROFIBUS
standard, with multimedia capabilities being provided by an adequate integration of TCP/IP protocols into
the PROFIBUS stack. From the operational point of view the integration of TCP/IP into PROFIBUS is by
itself a challenge, since the master-slave nature of the PROFIBUS MAC makes complex the
implementation of the symmetry inherent to IP communications. From the timeliness point of view the
challenge is two folded. On one hand the multimedia traffic should not interfere with the timing
requirements of the "native" control-related PROFIBUS traffic (typically hard real-time). On the other
hand multimedia traffic requires certain levels of quality-of-service to be attained. In this paper we
provide a methodology that enables fulfilling the timing requirements for both types of traffic in these
real-time industrial LAN. Moreover, we describe suitable algorithms for the scheduling support of
concurrent multimedia streams
Distributed Network System for Real-Time Model Based Control of Industrial Gas Turbines
This paper describes the development of a distributed network system for real-time model based control of industrial gas turbine engines. Distributed control systems contribute toward improvements in performance, testability, control system maintainability and overall life-cycle cost. The goal of this programme was to offer a modular platform for improved model based control system. Hence, another important aspect of this programme was real-time implementation of non-linear aero-thermal gas turbine models on a dedicated hardware platform. Two typical applications of real-time engine models, namely hardware-in-the-loop simulations and on-line co-simulations, have been considered in this programme. Hardware-in-the-loop platform has been proposed as a transitional architecture, which should lead towards a fully distributed on-line model based control system. Distributed control system architecture offers the possibility of integrating a real-time on-line engine model embedded within a dedicated hardware platform. Real-time executing models use engine operating conditions to generate expected values for measured and non-measured engine parameters. These virtual measurements can be used for the development of model based control methods, which can contribute towards improvements in engine stability, performance and life management. As an illustration of model based control concept, the example of gas turbine transient over-temperature protection is presented in this study
Simulation Study of Wired/Wireless Fieldbus Systems Using Store and Forward Mode
Fieldbus is a specific class of LAN technology, through which the communication process in industrial applications is integrated. The extent of using the wireless communications in most applications, leading to design hybrid wired/wireless fieldbus systems is based on standard PROFIBUS protocol. Because of the difference in physicalmedia such as bit rate and/or frame format between wired domain and wireless domain, there is a need to use a method to overcome traffic congestion that may occur in the intermediate systems as a result of the heterogeneity in the physical media. Within this work the intermediate systems (repeaters) are suggested to work as store-and-forward mode. The main objectives of this work is to develop simulation tools for the hybrid wired/wireless PROFIBUS architectures in order to perform behavioral study of such network protocols. The use of our developed simulation tools has indeed enabled us totest different network configurations and different parameters settings more easily, cheaper, and faster than in a real application