Search Results (4)

Slave devices in Ethernet-based fieldbus networks often require extensive reprogramming of applications and replacement of protocol stacks and Ethernet drivers whenever the fieldbus protocol needs to be changed. To address this challenge, we develop a common application programming interface (API) and stack interfaces that enable seamless protocol switching among EtherCAT, PROFINET, and EtherNet/IP without requiring protocol-specific code modifications. The real-time data exchange between the API and each protocol stack is realized in the stack interface by using the synchronization mechanism provided by FreeRTOS. The developed common API and stack interfaces facilitate the development of slave device applications that are universally compatible with multiple protocols, EtherCAT, PROFINET, and EtherNet/IP. Moreover, once a required protocol is selected in the integrated development environment (IDE) software before building the slave device firmware, the corresponding protocol stack and Ethernet drivers are automatically specified and the need to replace protocol stacks or Ethernet drivers is even eliminated when switching protocols. To validate the developed common API and stack interfaces, they were implemented on a slave device using TI’s TMDS243EVM board, and a fieldbus network was built by connecting the slave device to a master device executed by Beckhoff’s TwinCAT on a Windows PC. Experimental results confirmed the API’s functionality, reliability, and practical applicability in streamlining protocol management for Ethernet-based fieldbus networks. Full article

The synchronization control performance of the Fieldbus control system (FCS) is an important guarantee for the completion of multi-axis collaborative machining tasks, and its synchronization control accuracy is one of the decisive factors for the machining quality. To improve the synchronization control accuracy of FCS, this paper first makes a comprehensive analysis of the factors affecting synchronization in FCS. Secondly, by analyzing the communication model of linear Ethernet, a distributed clock compensation method based on timestamps is proposed to solve the asynchronous problem of communication data transmission in the linear ethernet bus topology. Then, based on the CANopen application layer protocol, the FCS communication and device control task collaboration method is proposed to ensure the synchronous control of multiple devices by FCS. Finally, an experimental platform is built for functional verification and performance testing of the proposed synchronization method. The results show that the proposed synchronization method can achieve a communication synchronization accuracy of 50 ns and a device control synchronization accuracy of 150 ns. Full article

Trends such as the Industrial Internet of Things and Industry 4.0 have increased the need to use new and innovative network technologies in industrial automation. The growth of industrial automation communications is an outcome of the shift to harness the productivity and efficiency of manufacturing and process automation with a minimum of human intervention. Due to the ongoing evolution of industrial networks from Fieldbus technologies to Ethernet, a new opportunity has emerged to harness the benefits of Software Defined Networking (SDN). In this paper, we provide a brief overview of SDN in the industrial automation domain and propose a network architecture called the Software Defined Industrial Automation Network (SDIAN), with the objective of improving network scalability and efficiency. To match the specific considerations and requirements of having a deterministic system in an industrial network, we propose two solutions for flow creation: the Pro-active Flow Installation Scheme and the Hybrid Flow Installation Scheme. We analytically quantify the proposed solutions that alleviate the overhead incurred from the flow setup. The analytical model is verified using Monte Carlo simulations. We also evaluate the SDIAN architecture and analyze the network performance of the modified topology using the Mininet emulator. We further list and motivate SDIAN features and report on an experimental food processing plant demonstration featuring Raspberry Pi as a software-defined controller instead of traditional proprietary Programmable Logic Controllers. Our demonstration exemplifies the characteristics of SDIAN. Full article

Networks of sensors and actuators in automated manufacturing processes are implemented using industrial fieldbuses, where automation units and supervisory systems are also connected to exchange operational information. In the context of the incoming fourth industrial revolution, called Industry 4.0, the management of legacy facilities is a paramount issue to deal with. This paper presents a solution to enhance the connectivity of a legacy Flexible Manufacturing System, which constitutes the first step in the adoption of the Industry 4.0 concept. Such a system includes the fieldbus PROcess FIeld BUS (PROFIBUS) around which sensors, actuators, and controllers are interconnected. In order to establish effective communication between the sensors and actuators network and a supervisory system, a hardware and software approach including Ethernet connectivity is implemented. This work is envisioned to contribute to the migration of legacy systems towards the challenging Industry 4.0 framework. The experimental results prove the proper operation of the FMS and the feasibility of the proposal. Full article