1,721,013 research outputs found
Ethernet powerlink
No full textEthernet POWERLINK (EPL) represents a prominent example of real-time Ethernet (RTE) communication networks. It belongs to the IEC 61784 International Standard [1], where it is referred to as the Communication Pro©le (CP) #1 within the CP Family #13
Performance analysis of PROFINET networks
No full textNowadays, Ethernet networks may be profitably employed also at the lowest levels of factory automation systems. Indeed, suitable application layer protocols for Ethernet have been recently developed in order to cope with the critical requirements imposed by the industrial applications. In this paper we focus on the protocols used by PROFINET, an emerging standard for industrial communications based on Ethernet, which is now available in two different versions, named CBA and IO. After a description of the protocols, we show the results of some tests aimed at evaluating the performances of such a network. In particular, we concentrate the attention on the times necessary to transfer limited amounts of data among stations. With regard to PROFINET CBA, the outcomes of an experimental set-up comprising several components, show, for the transfer times, highly variable values, dependent on the network load. Conversely, for PROFINET IO, the results of a set of numerical simulations we performed, allow to expect constant transfer times of some milliseconds, or even less, provided that an accurate time synchronization between stations is maintained
The impact of rate adaptation algorithms on wi-fi-based factory automation systems
Full text linkFactory automation systems based on the IEEE 802.11 Wi-Fi standard may benefit from its Multi-Rate Support (MRS) feature, which allows for dynamically selecting the most suitable transmission rate for the targeted application context. The MRS is implemented by means of rate adaptation algorithms (RAAs), which has already demonstrated to be effective to improve both timeliness and reliability, which are typically strict requirements of industrial real-time communication systems. Indeed, some of such algorithms have been specifically conceived for reliable real-time communications. However, the computational complexity of such algorithms has not been effectively investigated yet. In this paper, we address such an issue, particularly focusing on the execution times of some specific rate adaptation algorithms, as well as on their impact on the automation tasks. In this respect, after a formal description of the algorithms, we present the outcomes of an extensive experimental session, which includes practical measurements and realistic simulations. The obtained results are encouraging, since the measured execution times indicate that rate adaptation algorithms can be profitably adopted by industrial automation systems, allowing for improving their reliability and timeliness without impacting on the overall performance
A TSN-Based Technique for Latency Measurement in Real-Time Wireless Communication Networks
No full textAccurately measuring latencies in real-time communication systems is crucial for performance evaluation and theoretical modeling, especially in Industry 4.0/5.0 contexts. Enabling technologies such as Digital Twins (DTs), offer a pathway to design, fine-tune, and monitor systems remotely, their efficacy hinges on precise modeling of underlying physical components. Challenges arise particularly in accurately representing subsystems within communication networks, essential for remote control systems. In this paper, we propose an innovative approach to measure latency in wireless communication networks by characterizing individual subsystem components. Leveraging Time-Sensitive Networking (TSN) for synchronization, our methodology aims to provide insights into latency contributions from the protocol stack and Wireless Network Interface Controller (WNIC). Using relatively inexpensive hardware configured in monitor mode, we capture and timestamp raw wireless frames, enabling a comprehensive understanding of latency dynamics within communication networks
Wi-Fi based Functional Safety: An Assessment of the Fail Safe over EtherCAT (FSoE) protocol
No full textThe introduction of the Industrial Internet of Things (IIoT) is dramatically changing the concept of manufacturing, ensuring better production flexibility, efficiency, safety and security. In this scenario, Functional Safety Networks are ever more deployed, being networks that allow to implement functional safety systems, integrated and cooperating with factory communication infrastructures that are ever more characterized by the deployment of wireless communication systems. Unfortunately, nowadays, the lack of safety protocols targeted for wireless networks represents a bottleneck in the novel smart factory development process. Thus, functional safety over wireless is becoming a hot research topic. In this paper, we address the adoption of Wi-Fi to implement functional safety networks by exploiting the black channel approach, which is at the basis of the most popular functional safety protocols designed for wired networks. In practice, with such an approach, the safety protocol is not aware of the underlying communication system. We focus on a specific protocol, namely FailSafe over EtherCAT (FSoE) and investigate its behavior over Wi-Fi. To this aim, we developed an experimental set-up and conducted several tests to adequately assess safety, reliability and timing performance. Specifically, we addressed the achievable Safety Integrated Level (SIL), the number of network re-initializations and the message delivery times. The analysis provided encouraging results and revealed different behaviors concerned with the use of different transport layer protocols (TCP and UDP) that suggest interesting future activities
Time-Critical Wireless Networked Embedded Systems: Feasibility and Experimental Assessment
Full text linkIn this article, we investigate an innovative solution, to implement high sampling frequency industrial control by means of networked embedded systems connected via WiFi. The basic idea relies on a co-design approach for the control application, which is then able to adapt its sampling period, as well as to tune the Wi-Fi parameters, according to the feedback coming from the network. To this end, we implemented a cross-layer architecture acting at both application and data-link layers, which features a robust frame-delay state estimator, a time-efficient communication policy, and a specific tuning of the critical protocol parameters. Suitable hardware-in-the-loop experiments have been carried out exploiting two different embedded systems available off-the-shelf. The preliminary results, obtained from an extensive experimental campaign, are encouraging since they show that the proposed architecture enables industrial control applications requiring a sampling rate up to 1000 Hz, even in presence of communication impairments
A Profinet Simulator for the Digital Twin of Networked Electrical Drive Systems
No full textModern industrial manufacturing plants, especially those using coordinated electrical drives with strict timing requirements, make extensive use of real-time communication networks. These systems, typically, are based on various topologies, include diverse protocols, and connect devices from different manufacturers, which may make them difficult to study, plan and optimize. As a solution, the adoption of digital twins allows to simulate such systems under various operating conditions in a low-cost and zero-risk environment. In this paper we address the digital twin of a networked electrical drive system, focusing on the real-time communication network used to connect the drives. In particular, we describe the simulation model of Profinet IO RT Class 1, implemented as an extension of the INET library of OMNeT++. Moreover, we present the outcomes of the tests carried out on a prototype simulated network and compare them with those of the equivalent real one
Assessment of Different OPC UA Implementations for Industrial IoT-Based Measurement Applications
Full text linkThe industrial Internet of Things (IIoT) paradigm represents an attractive opportunity for new generation measurement applications, which are increasingly based on efficient and reliable communication systems to allow the extensive availability of continuous data from instruments and/or sensors, thus enabling real-time measurement analysis. Nevertheless, different communication systems and heterogeneous sensors and acquisition systems may be found in an IIoT-enabled measurement application, so that solutions need to be defined to tackle the issue of seamless, effective, and low-latency interoperability. A significant and appropriate solution is the open platform communications (OPCs) unified architecture (UA) protocol, thanks to its object-oriented structure that allows a complete contextualization of the information. The intrinsic complexity of OPC UA, however, imposes meaningful performance assessment to evaluate its suitability in the aforementioned context. To this aim, this article presents the design of a general yet accurate and reproducible measurement setup that will be exploited to assess the performance of the main open-source implementations of OPC UA. The final goal of this work is to provide a characterization of the impact of this protocol stack in an IIoT-enabled measurement system, in particular, in terms of both the latency introduced in the measurement process and the power consumption
A Profinet Simulator for the Digital Twin of Networked Electrical Drive Systems
Full text linkModern industrial manufacturing plants, especially those using coordinated electrical drives with strict timing requirements, make extensive use of real-time communication networks. These systems, typically, are based on various topologies, include diverse protocols, and connect devices from different manufacturers, which may make them difficult to study, plan and optimize. As a solution, the adoption of digital twins allows to simulate such systems under various operating conditions in a low-cost and zero-risk environment. In this paper we address the digital twin of a networked electrical drive system, focusing on the real-time communication network used to connect the drives. In particular, we describe the simulation model of Profinet IO RT Class 1, implemented as an extension of the INET library of OMNeT++. Moreover, we present the outcomes of the tests carried out on a prototype simulated network and compare them with those of the equivalent real one
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