Sebastian Schriegel

Hochschule Ostwestfalen-Lippe, Lemgo, North Rhine-Westphalia, Germany

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Publications (13)0 Total impact

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    ABSTRACT: The evolution of industrial communication inexorably moves towards Ethernet based networks. One important reason for using Ethernet at the shop floor is to participate on the continuous advancements of standard Ethernet. In contradistinction to the star topology, used commonly in home and office networks, in the industrial automation most common network structure is line. It is due to the fact that it simply follows the architecture of plants (production line). Depending on the size of an automation facility the size of such a network structure may contain up to 100 nodes. Thus, the node to node synchronization jitter, with its cumulative behavior, becomes a relevant performance factor for high demanding applications such as motion control. This paper examines influence of the synchronization jitter on the industrial Ethernet networks by taking the example of PROFINET IO, a common representative of an industrial Ethernet based protocol. It uses a Time Division Multiple Access (TDMA) procedure together with the communication scheduling to fulfill hard real-time requirements. Additionally the protocol uses Dynamic Frame Packing (DFP) in order to optimize bandwidth utilization. The efficiency of both mechanisms strongly depends on the node to node synchronization accuracy.
    2013 International IEEE Symposium on Precision Clock Synchronization for Measurement, Control and Communication, Lemgo, Germany; 10/2013
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    ABSTRACT: Ein anspruchsvoller Anwendungsbereich für industrielle Echtzeit-Ethernetsysteme (RTE) stellt die schnelle Sensor/Aktorvernetzung dar. Hier stellen die Einfachheit der Implementierung und die erreichbaren Transferzeiten wichtige Kriterien dar. Darüber hinaus ist die Feldebene der Automatisierungstechnik durch die Verwendung von Linienstrukturen, sowie einer geringer Nutzdatengröße pro Knoten gekennzeichnet. Die verschiedenen RTEs benutzen für die Rahmenbildung in der MAC-Schicht (Medium Access Control) entweder einen Individualrahmen. Die erreichbaren Transferzeiten werden durch die Zeit für das Senden der entsprechenden Rahmen (=Übertragungszeit) und der Laufzeit für die physikalische Ausbreitung des Rahmens vom Sender zum Empfänger begrenzt.
    VDI Kongress AUTOMATION 2013, Baden-Baden; 06/2013
  • VDI Kongress AUTOMATION 2013; 06/2013
  • B. Kroll, S. Schriegel, O. Niggemann, S. Schramm
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    ABSTRACT: This paper contributes a framework that helps to fulfill the requirements of the standards DIN EN 16247 and ISO 50001 by combining (i) a synchronized data acquisition, (ii) data integration, (iii) learning of normal behavior models and (iv) a implementation of an anomaly detection as prototype. Both standards require a reliable data acquisition and energy consumption analysis for implementing a certified energy management system. It shows that this framework meets the specifications of the standards by implementing a combined data acquisition and anomaly detection approach.
    Emerging Technologies & Factory Automation (ETFA), 2013 IEEE 18th Conference on; 01/2013
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    ABSTRACT: Scheduling of the communication in industrial net-works takes time. Since it has to be carried out every time a new network is brought to work, the time necessary to perform scheduling becomes a prominent factor. The approach presented in this paper, simplifies the schedul-ing problem of PROFINET IRT by resolving communica-tion conflicts by utilization of the dynamic frame packing (DFP) mechanism.
    2012 9th IEEE International Workshop on Factory Communication Systems (WFCS); 05/2012
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    ABSTRACT: This paper presents an approach for the enhancement of standard switch ASICs with real-time Ethernet functions. Whereas a standard switch ASIC provides sophisticated mechanisms for switching of non real-time frames, an attached FPGA implements cut-through switching of real-time frames. The proposed FPGA architecture supports configuration of port numbers, bandwidth reservation for real-time frames and utilizes flow-control mechanisms of the ASIC in order to keep frame buffer sizes low. Mapping exemplary RTE extensions of PROFINET IRT onto a Xilinx Spartan 6 FPGA demonstrates the capability of providing band-width reservation and cut-through-forwarding of real-time frames. Therefore, the approach benefits from the innovations made by the switch manufacturers, whereas only a small amount of functions has to be mapped onto an FPGA.
    Emerging Technologies & Factory Automation (ETFA), 2012 IEEE 17th Conference on; 01/2012
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    ABSTRACT: This paper presents the mapping of the High-Availability Seamless Redundancy (HSR) protocol to PROFINET RT. Whereas common PROFINET RT components that implement the Media Redundancy Protocol (MRP) are requiring up to 200 ms for recovery after link failures, HSR provides seamless redundancy. In order to overcome the incompatibilities between PROFINET and HSR a configurable HSR RedBox is implemented. The hardware architecture, running at 100 MHz, is mapped onto an Altera Stratix IV FPGA and is capable of processing up to 100 Mbps per port. Using several RedBoxes in a ring, a seamless redundancy is demonstrated for a PROFINET RT test network, using 1 ms cycle time with 3 ms watchdog. The presented architecture is highly configurable and can be mapped both to high-end and low-end FPGAs and therefore fulfills industrial requirements.
    Factory Communication Systems (WFCS), 2012 9th IEEE International Workshop on; 01/2012
  • Christian Hallas, Daniel Kirschberger, Sebastian Schriegel
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    ABSTRACT: Um in verteilten Systemen Echtzeit gewährleisten zu können ist eine hochgenaue Zeitsynchronisation in den verteilten Knoten erforderlich. Hier hat sich in den letzten Jahren für Ethernet-Netzwerke der Standard IEEE 1588 etabliert. Für hochgenaue 1588-Implementierungen ist ein gut aufeinander abgestimmtes Hardware-/ Software-Co-Design erforderlich. Insbesondere die deterministische Verarbeitung von Synchronisationstelegrammen innerhalb der Geräte, und die Berechnungen von Regelalgorithmen zur Kontrolle der Laufgeschwindigkeit der lokalen Uhrwerke, sind eine besondere Herausforderung. Daher wird in dieser Arbeit ein Testgerät vorgestellt, welches IEEE 1588-Implementierungen auf Synchronisationsgenauigkeit unter wechselnden Umgebungsbedingungen testet. Umgebungsbedingungen, wie sie im industriellen Umfeld auftreten, sind beispielsweise schwankende Temperatur oder mechanische Belastungen. Die Architektur des Testgerätes muss die Möglichkeit bieten, diese Bedingungen zu emulieren.
    01/2011;
  • Sebastian Schriegel, D. Kirschberger, H. Trsek
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    ABSTRACT: The IEEE 1588 standard is widely established and accepted for clock synchronization in Ethernet networks. High accuracy IEEE 1588 implementations require a well-coordinated hardware/software co-design. Processing of sophisticated control algorithms for the time speed of local clocks within synchronization slaves are particularly important. Hence, IEEE 1588 implementations should be tested with respect to certain performance indicators like control loop behavior and synchronization accuracy. Furthermore, interoperability with other devices and standard compliance also need to be considered. The achievable synchronization accuracy depends on environmental conditions, network load and network topology. A test system should be able to emulate these physical conditions. This requires a well-founded knowledge about influences on IEEE 1588 implementations caused by both, environmental conditions and network load. This could be a frequency drift of crystal caused by either temperature variations or mechanical stress. Unfortunately, the standard does not specify an expected behavior in such an environment. Due to lack of standardization and test methods, a system-wide guarantee for synchronization accuracy can only be given for proprietary closed systems. In this paper a reproducible test environment with the ability to emulate environmental conditions is presented, followed by an evaluation of two exemplary implementations. The possibility to guarantee synchronization accuracy with the help of appropriate certification tests in such a specific test environment will be demonstrated.
    01/2010;
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    S. Schriegel, H. Trsek, J. Jasperneite
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    ABSTRACT: Communication networks for industrial automation are usually heterogeneous, i.e. a combination of different wired and wireless technologies. A possible setup could be a Real-time Ethernet (RTE) extended by a wireless local area network (WLAN) for all mobile system components. However, the required clock synchronization with IEEE 1588v2 for such a system can only be accomplished for the wired RTE part. Currently, incorporating standard network components without IEEE 1588v2 support (e.g. switches, wireless links, etc.) into a certain synchronization domain leads to a decreased synchronization accuracy which is unacceptable for most applications. Hence, this paper introduces a novel approach for a protocol enhancement to enable clock synchronization when having devices without IEEE 1588v2 support inside a synchronization domain. The proposed approach compensates non-deterministic forwarding delays of synchronization frames by using different send rates for Sync messages. Basically, the Sync message send rate on a connection with a high forwarding jitter has to be high, links with a smaller jitter can use a lower Sync send rate. In order to achieve this, synchronization devices with the ability to scale the aforementioned send rate are necessary and have been realized. They are evaluated in a real setup consisting of a RTE with a wireless extension.
    Precision Clock Synchronization for Measurement, Control and Communication, 2009. ISPCS 2009. International Symposium on; 11/2009
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    ABSTRACT: Industrial Ethernet switches, form the network backbone in automotive production, substation automation systems, intelligent transport systems, and other major industrial automation projects. In the operation of industrial switches, the recovery time of a switch is vital for its applicability. In the last few years, a large number of solutions have emerged among the switch manufacturers which have been accompanied by standardisation activities in IEC. This paper gives a brief introduction of the industrial requirements for network redundancy and discusses details of existing solutions with a special focus on the ring topology. A possible optimisation of existing Ethernet based industrial switches is also discussed.
    8th IFAC International Conference on Fieldbuses and Networks in Industrial and Embedded Systems (2009); 05/2009
  • S. Schriegel, J. Jasperneite
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    ABSTRACT: Networked Industrial Devices must fulfill requirements regarding temperature ranges, noise immunities, and mechanical loads (e.g. DIN EN 60068-2-6). The effects of these environmental conditions on the stability of the frequency of clock sources are well studied [1, 2]. However the influence on the synchronization characteristics of IEEE 1588 can be derived only partly from these investigations. The dependency between the frequency drift (df/dt) and the transmission period of the synchronization frames T is very important for the achievable accuracy of IEEE 1588-based networks. In order to examine these effects, a novel measuring method is proposed in this paper. The results of exemplary measurements at a crystal oscillator with different temperature and mechanical loads will be discussed. These results are compared with the existing requirements for industrial communication systems, especially for the Industrial Ethernet system PROFINET. The objective is to derive coherences and rules for the implementation of functional components of the synchronization procedure.
    Precision Clock Synchronization for Measurement, Control and Communication, 2007. ISPCS 2007. IEEE International Symposium on; 11/2007
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    Sebastian Schriegel, Jürgen Jasperneite
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    ABSTRACT: Künftige Smart Grids stellen hochgradig vernetzte Systeme mit einem prognostizierten Umfang des heutigen Internets dar. Hierbei wird Automatisierungs- und Kommunikationstechnik eingesetzt, die neue Herausforderungen bezüglich Datensicherheit- und Datenschutz zu erfüllen hat. Dieser Beitrag zeigt die Anforderungen an IKT-Systeme für ein zukünftiges heterogenes, dezentrales und intelligentes Energiesystem unter Berücksichtigung aktueller und zu erwartender Datensicherheits- und Datenschutzanforderungen auf.
    e & i Elektrotechnik und Informationstechnik 129(4).