Proceedings ArticleDOI
Enhancements to the time synchronization standard IEEE-1588 for a system of cascaded bridges
Jurgen Jasperneite,K. Shehab,Karl Weber +2 more
- pp 239-244
TLDR
In this paper, a bypass clock instead of the boundary clock is proposed as an enhancement of the IEEE-1588 standard for bridged networks, where the local clock adjustment can be modeled by a corresponding control loop.Abstract:
The IEEE-1588 standard for a high precision time synchronization now exists since 2002. For using this standard in bridged networks a so-called boundary clock is defined, where the local clock adjustment can be modeled by a corresponding control loop. At the field level of industrial automation systems, the line topology is very important. By using Ethernet at the field level, the resulting chain of bridges leads to a cascade of control loops and may lead to instabilities and deviations of the distributed clocks, which are not acceptable. For this application a bypass clock instead of the boundary clock is proposed as an enhancement of the IEEE-1588 standard. The effectiveness of this extension to be evaluated by simulation technique.read more
Citations
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Journal ArticleDOI
Globally Synchronized Time via Datacenter Networks
TL;DR: The Datacenter Time Protocol is presented, a clock synchronization protocol that does not use packets at all, but is able to achieve nanosecond precision and is demonstrated that the precision provided by DTP in hardware is bounded by 4TD.
Patent
Using depth-camera images to speed registration of three-dimensional scans
TL;DR: In this article, a 3D scanner measures a first collection of 3D coordinates of points from a first registration position and a second collection of points of origin from a second registration position, and a processor determines first and second translation values and a first rotation value based on the depth-camera images.
Journal ArticleDOI
A Servo-Clock Model for Chains of Transparent Clocks Affected by Synchronization Period Jitter
TL;DR: This paper proposes an optimal servo-clock in the mean square sense that relies on both a Kalman filter that estimates the clock state difference with respect to the master and a static-state feedback assuring mean square stability even under the effect of significant fluctuations of the synchronization period.
Journal ArticleDOI
A Novel Method for Providing Precise Time Synchronization in a Distributed Control System Using Boundary Clock
Jae-Hun Cho,Hoon Kim,Sihai Wang,Jaehoon Lee,Han-Lim Lee,Seong-taek Hwang,Sung-Dae Cho,Yun-Je Oh,Tae-Jin Lee +8 more
TL;DR: The proposed scheme can be used to improve the time synchronization performance in IEEE 1588-compliant control systems using boundary clock and the experimental results show that the performance of time synchronization is dominated by fast jitter rather than frequency error and wander.
Journal ArticleDOI
IEEE 1588 for Clock Synchronization in Industrial IoT and Related Applications: A Review on Contributing Technologies, Protocols and Enhancement Methodologies
TL;DR: This study has compared the well-known synchronization techniques and concluded that the PTP is the most appropriate answer to robust clock synchronization though challenges are there that requires thoughtful efforts and modification in the current version.
References
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Internet time synchronization: the network time protocol
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Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems
Kang B. Lee,J Eldson +1 more
TL;DR: A protocol is provided in this standard that enables precise synchronization of clocks in measurement and control systems implemented with technologies such as network communication, local computing, and distributed objects.
Proceedings ArticleDOI
IEEE 1588 standard for a precision clock synchronization protocol for networked measurement and control systems
J C. Eidson,Kang B. Lee +1 more
TL;DR: This paper discusses the major features and design objectives of the IEEE-1588 standard, designed to serve the clock synchronization needs of industrial systems, and recent performance results of prototype implementations of this standard in an Ethernet environment are presented.
Journal ArticleDOI
Precision synchronization of computer network clocks
TL;DR: In this article, the authors describe a series of incremental improvements in system hardware and software which result in significantly better accuracy and stability, especially in primary time servers directly synchronized to radio or satellite time services.