Industrial Ethernet, Third Edition

John Marshall

• Publisher: International Society of Automation
• Year: 2017
• Print ISBN: 9781945541049
• eBook ISBN: 9781643310978
• Topic: Technology & Engineering
• Subtopic: Civil Engineering
• Index: Technology & Engineering

This is the go-to guidebook for people who need to fully understand factory floor Ethernet and for those who need to have a basic understanding of Ethernet and TCP/IP terminology, Ethernet hardware, Ethernet software, and the Internet of Things (IoT). From this latest edition, you will learn about the Industrial Internet of Things (IIoT), Ethernet rings, daisy-chaining Ethernet devices, synchronizing devices over Ethernet, Ethernet security, and what Microsoft, Oracle, and Amazon are doing to move industrial data into their cloud platforms. You will quickly gain a solid grasp of Ethernet basics, the constraints of the industrial environment, and the specialized requirements of machine control. Practical reference charts and installation, maintenance, troubleshooting, and security tips make this book an ideal quick reference resource at project meetings and on the job. Topics covered in the book include signaling types, web services, Power over Ethernet, wireless Ethernet, and an expansive focus on Ethernet and IoT protocols and addressing. After reading this book, you will be able to plan industrial Ethernet installations with realistic expectations, make knowledgeable purchasing decisions, as well as identify and prevent common causes of failure.

1.0

What Is Industrial Ethernet?

1.1Introduction

Industrial Ethernet is the successful application of IEEE 802.3 standards with wiring, connectors, and hardware that meet the electrical noise, vibration, temperature, and durability requirements of factory equipment, as well as network protocols that provide interoperability and time-critical control of smart devices and machines.

Industrial Ethernet is a specialized, rigorous application of standard “office Ethernet” technology that adds any or all the following requirements:

•Mission critical – Downtime is much less tolerable in the factory than the office. When an office network goes down, you go get a cup of coffee and check your email later. When a factory goes down, you choke down your last mouthful of coffee, run into the plant, and fix the problem as fast as possible! The effects of downtime are less isolated in a manufacturing facility.

•Harsh environment – Factory equipment is not usually installed in air-conditioned hall closets. It’s more likely to be bolted to a robotic welder or oil rig. Temperature extremes and vibration threaten garden-variety hardware, cables, and connectors. Device selection, installation, and proper wiring practices are crucial.

•Electrical noise – Ordinary 110 VAC circuits are not the norm in factories. Industrial Ethernet devices are often used with high-current 480 VAC power lines, reactive loads, radios, motor drives, and high-voltage switchgear. Network communication must continue reliably despite these hazards.

•Vibration – Industrial Ethernet “smart devices” are, by definition, mounted on machines. Machines move and shake. Velcro and “telephone connectors” may not be up to the task.

•Powered devices – Certain devices must be powered by the network cable itself. Many automation devices operate at 24 VDC. Many devices are now powered directly from the Ethernet network.

•Security – The data in your factory is not necessarily more worthy of protection than the data in your office, but the threats are different. Factory equipment is vulnerable to hackers, of course, but accidental disruptions created by yourself or your staff are much more likely. Specific precautions must be taken.

•Legacy devices – Real automation systems are a mix of new, nearly new, old, older, and pre-Mesozoic Era equipment from incompatible vendors. Industrial Ethernet must link serial protocols, legacy networks, and fieldbuses.

•Interoperability – Ethernet devices must communicate with each other, with PCs, with enterprise business systems, and with cloud applications. The existence of an Ethernet jack is no guarantee of openness, interoperability, or compatibility. You must ask the right questions when making purchases.

•Levels of priority – Some machine-control information requires real-time, deterministic responses. Other data is much less urgent. It’s important to recognize different priority levels for different kinds of data.

•Performance – Beyond physical robustness are subtle characteristics of software drivers, routers, and switches, such as hidden latency, jitter, limited connection, and behavior under erratic conditions.

•Connectivity to other local area networks (LANs) – Most Industrial Ethernet systems must be bridged to business intranets and the Internet. Serious problems can be introduced on both sides if this is not done with care.

•The IT department versus the automation department – Ethernet is precisely the place where two equally valid but conflicting views of “systems” and “data” come together. You must proceed with care to avoid a battle between company fiefdoms, all-out mutiny, or even a brand new pair of cement shoes.

•Mastery of the basics – No matter how good your equipment is, if you don’t apply proper knowledge of Ethernet, Transmission Control Protocol/Internet Protocol (TCP/IP), and sound installation practices, your system will never work right.

Industrial Ethernet is a reference book that addresses each of these concerns and lays down the basic nuts and bolts of Ethernet and TCP/IP. After reading this book, you’ll know the basics of the world’s most popular network, you’ll be able to plan Ethernet projects, and you’ll know the right questions to ask when you talk to vendors.

Ethernet is the worldwide de facto standard for linking computers together. Ethernet connects hundreds of millions of computers and smart devices across buildings, campuses, cities, and countries. Cables and hardware are widely available and inexpensive (“dirt cheap” in the case of ordinary officegrade products), and software is written for almost every computing platform.

Ethernet is now a hot topic in automation, where industry-specific networks have dominated: PROFIBUS, DeviceNet, Modbus, Modbus Plus, Remote I/O, Genius I/O, Data Highway Plus, FOUNDATION Fieldbus, and numerous serial protocols over the electrical standards of EIA RS-232, RS-422, and RS-485.

In some cases, Ethernet is displacing these networks. In nearly all cases, Ethernet is being used in demanding installations alongside them. This book gives a basic understanding of Ethernet’s strengths, weaknesses, fundamental design rules, and application guidelines. It addresses the unique demands of the factory environment, intelligent devices, and the most common automation applications and protocols. Industrial Ethernet provides basic installation and troubleshooting recommendations to help your projects work right the first time.

1.2A Very Short History of Ethernet and TCP/IP

Ethernet originated at Xerox Palo Alto Research Center (PARC) in the mid-1970s. The basic philosophy was that any station could send a message at any time, and the recipient had to acknowledge successful receipt of the message. It was successful and in 1980 the DIX Consortium (Digital Equipment Corporation, Intel, and Xerox) was formed, issuing a specification, Ethernet Blue Book 1, followed by Ethernet Blue Book 2. This was offered to the Institute of Electrical and Electronics Engineers (IEEE, www.ieee.org), who in 1983 issued the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) specification—their stamp of approval on the technology.

Ethernet has since evolved under IEEE to encompass a variety of standards for copper, fiber, and wireless transmission at multiple data rates.

Ethernet is an excellent transmission medium for data, but by itself falls short of offering a complete solution. A network protocol is also needed to make it truly useful, and TCP/IP has evolved alongside of Ethernet.

The big push toward TCP/IP came in the mid-1980s when 20 of the largest U.S. government departments, including the U.S. Department of Defense, decreed that all mainframes (read: expensive computers) to be purchased henceforth required a commercially listed and available implementation of UNIX to be offered. The department didn’t necessarily need to use UNIX for the project at hand, but after “the project” was completed, the government wanted the ready option to convert this expensive computer into a general-purpose computer.

This soon meant that all serious computer systems in the world had relatively interoperable Ethernet and TCP/IP implementations. So IBM had Systems Network Architecture (SNA), TCP/IP, and Ethernet on all of its computers. Digital Equipment Corporation (DEC) had DECnet, TCP/IP, and Ethernet on all of its computers. Add a few more examples (Cray, Sun, CDC, Unisys, etc.) and you soon see that the only true standard available on all computers was a TCP/IP plus Ethernet combination. Both from a historical view, as well as in today’s industrial world, the TCP/IP plus Ethernet marriage is a key combination. Neither would have survived or prospered without the other.

2.0

A Brief Tutorial on Digital Communication

Digital communication is the transmission of data between two or more intelligent devices in a mutually agreed upon electronic format (e.g., binary, octal, EBCDIC, and ASCII). The following components are necessary to accomplish this:

•Data source

•Transmitting electronics

•Communications media

•Receiving electronics

•Data destination

The fundamentals of communication are the same, regardless of the technology. Confusion about any aspect can usually be helped with direct analogies to more familiar modes of communication such as multiple people engaged in a convers...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• About the Authors
• Acknowledgments
• 1.0 What Is Industrial Ethernet?
• 2.0 A Brief Tutorial on Digital Communication
• 3.0 Ethernet Hardware Basics
• 4.0 Ethernet Protocol and Addressing
• 5.0 Basic Ethernet Building Blocks
• 6.0 Network Health, Monitoring, and System Maintenance
• 7.0 Installation, Troubleshooting, and Maintenance Tips
• 8.0 Ethernet Industrial Protocols, Fieldbuses, and Legacy Networks
• 9.0 Basic Precautions for Network Security
• 10.0 Power over Ethernet (PoE)
• 11.0 Wireless Ethernet
• 12.0 Advanced Hardware Topics
• 13.0 The Internet of Things
• 14.0 Factory Floor/Enterprise Communications
• 15.0 The Alphabet Soup of the Internet of Things
• Index