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Industrial Ethernet Guide - Determinacy and Real-Time Control (The Hunt for CSMA/CD)
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.Any solution attempting to achieve true determinacy and real-time control based on Ethernet TCP/IP requires the elimination of the CSMA/CD, IP, and UDP components, because their combined characteristics contribute to unpredictable cycle times and additional jitter.CSMA/CD can be easily eliminated through the use [...]
Industrial Ethernet Guide - Classification of Industrial Ethernet Protocols
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.Note: This chapter represents a paradox in so far that it proves that a credible classification of Industrial Ethernet protocols based on performance characteristics, despite many such attempts, does not exist. Too many conflicting performance tests added to the confusion not only for [...]
Industrial Ethernet Guide - Industrial Ethernet Protocols
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.Note: It is important to re-iterate the point that a sufficiently detailed description of each protocol involved is clearly outside the scope of this book. Complete documents are provided by the respective manufacturers or standardization/user organizations, even though they usually provide little educational [...]
Industrial Ethernet Guide - Ethernet TCP/IP for Process Control
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.Given all the technical aspects of Ethernet TCP/IP, including its strengths and weaknesses, that have been presented thus far, the critical engineering mind may challenge the need for sophisticated Industrial Ethernet protocols.After all, all Industrial Ethernet protocols benefit from the vast speed of Ethernet TCP/IP. Random delays [...]
Industrial Ethernet Guide - “Hard” and “Soft” Real-Time Control
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.“Hard” real-time (HRT) control systems are designed to support specific response times, and thus, they are highly deterministic, but they depend on stable cycle time. A missed deadline may post a safety hazard or other serious consequences.“Soft” real-time (SRT) systems deliver a best-effort response, and there is [...]
Industrial Ethernet Guide - Execution Speed and Determinacy
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.High-speed and high-precision manufacturing equipment such as, for instance, a robotic arm utilizes electric components like motion controllers, programmable logic controllers (PLC), feedback devices, and more, and it is mandatory for the machine’s performance that these components work together in a synchronized fashion. [...]
Industrial Ethernet Guide - Ethernet TCP/IP and Real-Time Performance
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.The demand for Ethernet as a real-time communication network has increased continuously in the past due to the benefits of employing a single network technology throughout the manufacturing facility, from office to plant floor.However, the unpredictable nature of Ethernet TCP/IP’s timing (which will [...]
Industrial Ethernet Guide - Network Segmentation
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.When too many devices are attached to a single-cable network, it is advisable to break up the network into separate, smaller network segments, and thus creating Multiple Collision Domains. The primary reason for segmenting is to increase bandwidth and to span the network over [...]
Industrial Ethernet Guide - Limitations Of Ethernet
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.There are, in fact, only few limitations to Ethernet as a standard networking technology, and those that exist can be rectified easily.There are practical limits to the size (physical network length, number of devices) of a complete Ethernet network that shares a single [...]
Industrial Ethernet Guide - Ethernet, CSMA/CD, TCP/IP, and UDP
The following is part of A Comprehensible Guide to Industrial Ethernet by Wilfried Voss.The following chapter explains, in brief, the functionality of Ethernet, CSMA/CD (Carrier-sense multiple access with collision detection), TCP/IP (Transmission Control Protocol / Internet Protocol), and UDP (User Datagram Protocol).EthernetEthernet represents the physical protocol layer, i.e., it covers the physical medium (e.g., cables, RJ45 ports, LAN cards, [...]