Measuring the impact of vertical integration on response times in ethernet fieldbuses

Denis, B.; Ruel, Silvain; Faure, Jean-Marc; Marsal, Gaëlle; Frey, Georg

doi:10.1109/efta.2007.4416815

Cited by 20 publications

(23 citation statements)

References 13 publications

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“…However, results obtained by measurements (Denis et al [2007]) on this kind of architecture showed that, in spite of this complexity, the load of the fieldbus does not impact the transmission delays. Thus, for the communication between two components, the network can be assumed perfect (no limit of throughput, no congestion) and modelled as a constant delay.…”

Section: Networkmentioning

confidence: 99%

Efficient representation for formal verification of time performances of networked automation architectures

Ruel

Smet

Faure

2008

IFAC Proceedings Volumes

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Networked automation architectures with Ethernet-based fieldbuses instead of traditional fieldbuses are more and more often used in industry, even for critical systems such as chemical or nuclear power plants. The strong safety requirements of these processes impose to evaluate the time performances of these complex architectures. Formal verification techniques are promising solutions to reach this objective. Hence, this paper focuses on the applicability of formal verification techniques to check time performances. On the basis of a case study, it is shown how formal models of networked automation architectures which are simple enough to be checked by existing timed model-checkers while yielding meaningful results can be developed.

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Section: Networkmentioning

confidence: 99%

Efficient representation for formal verification of time performances of networked automation architectures

Ruel

Smet

Faure

2008

IFAC Proceedings Volumes

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“…Such assumptions are often taken for granted in the context of NAS [11], as is the case in our study, for two main reasons: -The exchanged data packets are of a short length, and just a few bytes are sufficient to transmit data. With Modbus for instance, the request can reach up to 256 bytes only [2].…”

Section: Timed Event Graphs and Max-plus Algebramentioning

confidence: 99%

“…As a matter of fact, the PLC modules are not synchronized and RIOMs may be shared across many applications, which leads to delays that must then be incorporated. To the best of our knowledge, studies that consider the entire architecture (both field devices and the network) are still quite rare and often informally based on case simulation or experimental measurements targeting a limited number of systems [10], [11]. The only formal method developed has been based on model-checking [12] aiming to check if a timing property holds or not.…”

Section: Introductionmentioning

confidence: 99%

Analytic Calculus of Response Time in Networked Automation Systems

Addad¹,

Amari²,

Lesage³

2010

IEEE Trans. Automat. Sci. Eng.

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-This paper presents a novel approach to evaluate the response time in networked automation systems (NAS) that use a client/server protocol. The developments introduced are derived from modeling the entire architecture in the form of timed event graphs (TEGs), as well as from the resulting state representation in Max-Plus algebra. The various architectural stages are actually modeled in a very abstract pattern, which yields just those TEG models where local delays are sufficient to perform the overall evaluation. In this manner, linear Max-Plus equations are obtained. A thorough analysis of these equations has led to analytical formulas for direct calculus of NAS response time. As a final step, experimental measurements taken on a laboratory facility have been used to verify the validity of the results. In conclusion, the benefit and effectiveness of this novel method have been demonstrated.Note to Practitioners-In this work, we present an overall study of networked automation systems working according to client/server paradigm. Unlike systems where a global scheduling of the shared resources is available and the delays well handled, in such systems it is not the case and the investigations to evaluate their real-time performances are required. Actually, these systems are very present in industry but the efforts to deal with this issue are rare and often informal, based on simulation of particular cases. In our work, we assess a major criterion of their time performances, the response time. We give a formal evaluation of this feature through an analytic approach. The results we present are generic and fit the experimental observations in different cases.

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“…The three steps of this strategy, that might be automated, will be sketched in this section and are explained with more details in Ruel et al (2008). (Marsal (2006) and Denis et al (2007)); then, the duration of an exchange between one PLC and one RIOM does not depend on the other exchanges.…”

Section: Modelling the Automation Systemmentioning

confidence: 99%

“…Nevertheless, it matters to avoid synchronization between the input signal and the IOscanning cycle to prevent from meaningless measures. Then the frequency of the input signal must be set as explained in Denis et al (2007).…”

Section: Fig 3 Response Time Measurementmentioning

confidence: 99%

Finding the Bounds of Response Time of Networked Automation Systems by Iterative Proofs

Ruel¹

2009

13th IFAC Symposium on Information Control Problems in Manufacturing

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Response time of modern automation systems is not constant but is featured by a distribution of values; finding the upper and lower bounds of this distribution is a crucial issue when designing critical systems. This paper shows how to obtain these bounds by proving timed properties on a formal model of the system, in the form of communicating timed automata. In this approach, bounds are obtained by iterative proofs of properties which are expressed by means of a parametric observer. Comparison of analysis results of formal models to measures on real automation systems shows the accuracy and interest of this approach.

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Measuring the impact of vertical integration on response times in ethernet fieldbuses

Abstract: Abstract

Cited by 20 publications

References 13 publications

Efficient representation for formal verification of time performances of networked automation architectures

Efficient representation for formal verification of time performances of networked automation architectures

Analytic Calculus of Response Time in Networked Automation Systems

Finding the Bounds of Response Time of Networked Automation Systems by Iterative Proofs

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