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http://dx.doi.org/10.3795/KSME-A.2014.38.7.785

Evaluation of EtherCAT Clock Synchronization in Distributed Control Systems  

Kim, Woonggy (Dept. of Mechanical and Information Engineering, Univ. of Seoul)
Sung, Minyoung (Dept. of Mechanical and Information Engineering, Univ. of Seoul)
Publication Information
Transactions of the Korean Society of Mechanical Engineers A / v.38, no.7, 2014 , pp. 785-797 More about this Journal
Abstract
Support for the precise time synchronization of EtherCAT, known as distributed clock (DC), enables the design of highly synchronized operations in distributed real-time systems. This study evaluates the performance of the EtherCAT DC through extensive experiments in a real automation system. We constructed an EtherCAT control system using Xenomai and IgH EtherCAT stack, and analyzed the clock deviation for different devices in the network. The results of the evaluation revealed that the accuracy of the synchronized clock is affected by several factors such as the number of slave devices, period of drift compensation, and type of system time base. In particular, we found that careful decision regarding the system time base is required because it has a fundamental effect on the master operation, which results in significantly different performance characteristics.
Keywords
EtherCAT; Clock Synchronization; Performance Evaluation; Real-time Ethernet; Distributed System;
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Times Cited By KSCI : 1  (Citation Analysis)
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1 Ingram, D. M. E., Schaub, P., Campbell, D. A. and Taylor, R. R., 2013, "Performance Analysis of PTP Components for IEC 61850 Process Bus Applications," IEEE Trans. Instrumentation and Measurement, Vol. 62, No. 4, pp. 710-719.   DOI   ScienceOn
2 Scheiterer, R. L., Na, C., Obradovic, D. and Steindl, G, 2009, "Synchronization Performance of the Precision Time Protocol in Industrial Automation Networks," IEEE Trans. Instrumentation and Measurement, Vol. 58, No. 6, pp. 1849-1857.   DOI   ScienceOn
3 Schriegel, S. and Jasperneite, J., 2007, "Investigation of Industrial Environmental Inuences on Clock Sources and their Effect on the Synchronization Accuracy of IEEE 1588," Proc. of the IEEE Int. Symp. Precision Clock Synchronization for Measurement, Control and Communication (ISPCS), pp. 50-55.
4 Loschmidt, P., Exel, R., Nagy, A. and Gaderer, G. 2008, "Limits of Synchronization Accuracy using Hardware Support in IEEE 1588," Proc. of the IEEE Int. Symp. Precision Clock Synchronization for Measurement, Control and Communication (ISPCS), pp. 12-16.
5 Milevsky, A. and Walrod, J., 2008, "Development and Test of IEEE 1588 Precision Timing Protocol for Ocean Observatory Networks," Proc. of the IEEE OCEANS 2008, pp. 1-7.
6 Lee, J., Kim, C., Kim, I., Kim, Y. and Kim, T., 2014, "Implementation and Validation of EtherCAT Support in Integrated Development Environment for Synchronized Motion Control Application," Trans. Korean Soc. Mech. Eng. A, Vol. 38, No. 2, pp. 211-218.   과학기술학회마을   DOI   ScienceOn
7 Ferrari, P., Flammini, A., Marioli, D. and Taroni, A., 2008, "A Distributed Instrument for Performance Analysis of Real-Time Ethernet Networks," IEEE Trans. Industrial Informatics, Vol. 4, No. 1, pp. 16-25.   DOI   ScienceOn
8 Robert J., Georges J. P., Rondeau E. and Divoux T., 2012, "Minimum Cycle Time Analysis of Ethernet-Based Real-Time Protocols," Int. J. Comput. Commun., Vol. 7, No. 4, pp. 743-757.
9 Sung, M., Kim, I. and Kim, T., 2013, "Toward a Holistic Delay Analysis of EtherCAT Synchronized Control Processes," Int. J. Comput. Commun., Vol. 8, No. 4, pp. 608-621.   DOI
10 Cena, G., Bertolotti, I. C., Scanzio, S., Valenzano, A. and Zunino, C., 2012, "Evaluation of EtherCAT Distributed Clock Performance," IEEE Trans. Industrial Informatics, Vol. 8, No. 1, pp. 20-29.   DOI   ScienceOn
11 Cereia, M., Bertolotti, I. C. and Scanzio, S., 2011, "Performance of a Real-Time EtherCAT Master Under Linux," IEEE Trans. Industrial Informatics, Vol. 7, No. 4, pp. 679-687.   DOI   ScienceOn
12 Cena, G., Bertolotti, I., Scanzio, S., Valenzano, A. and Zunino, C. 2010, "On the Accuracy of the Distributed Clock Mechanism in EtherCAT," Proc. of the IEEE Int. Workshop Factory Communication Systems, pp. 43-52.
13 Xenomai. http://www.xenomai.org.
14 IgH EtherCAT Master for Linux. http://www.etherlab.org.
15 Single-Chip Muilti-Function 10/100Mbps Ethernet Controller with Power Management Datasheet, RealTek, Inc., Rev. 1.2, 2005.
16 Hardware Data Sheet - ET1100: EtherCAT Slave Controller, Beckhoff, ver. 1.8, 2010.
17 Orfanus, D., Indergaard, R., Prytz, G. and Wien, T., 2013, "EtherCAT-based Platform for Distributed Control in High-performance Industrial Applications," Proc. of the IEEE Conf. Emerging Technol. Factory Autom., pp. 1-8.
18 MSO3000 and DPO3000 Series Digital Phosphor Oscilloscopes User Manual, Tektronix, Inc., 2012, P/N: 071265602.
19 Soni, M., 2012, "White Paper: EtherCAT on Sitara AM335x ARM Cortex-A8 Microprocessors." ARM microprocessor group, Texas Instruments.
20 Ramesh, R., Jyothirmai, S. and Lavanya, K., 2013, "Intelligent Automation of Design and Manufacturing in Machine Tools using an Open Architecture Motion Controller," Journal of Manufacturing Systems, Vol. 32, No. 1, pp. 248-259.   DOI   ScienceOn
21 Felser, M., 2010, "Real Time Ethernet: Standardization and Implementations," Proc. of the IEEE International Symposium on Industrial Electronics (ISIE), pp. 3766-3771.
22 Benzi, F., Buja, G. and Felser, M., 2005, "Communication Architectures for Electrical Drives," IEEE Trans. Industrial Informatics, Vol. 1, No. 1, pp. 47-53.   DOI   ScienceOn
23 EtherCAT Technology Group, "EtherCAT: Ethernet for Control Automation Technology." http://www.ethercat.org.
24 Kim, K., Sung, M. and Jin, H. W., 2012, "Design and Implementation of a Delay- Guaranteed Motor Drive for Precision Motion Control," IEEE Trans. Industrial Informatics, Vol. 8, No. 2, pp. 351-365.   DOI   ScienceOn
25 Jasperneite, J., Schumacher, M. and Weber, K. 2007, "Limits of Increasing the Performance of Industrial Ethernet Protocols," Proc. of the IEEE Int. Conf. Emerging Technol. Factory Autom., pp. 17-24.
26 Seno, L., Vitturi, S. and Zunino, C., 2009, "Real Time Ethernet Networks Evaluation Using Performance Indicators," Proc. of the IEEE Conf. Emerging Technol. Factory Autom., pp. 1-8.