EtherCAT: Ethernet for automation, best practices

Integrating Ethernet into automation can start at the lowest levels, continue through process control level for controller-to-controller networking, on to the enterprise network level for SCADA and reporting. Ethernet can be the only network used to conduct the business of manufacturing.


EtherCAT Automation Protocol (EAP) enables communication between controllers to exchange process parameters, distribute non-real-time parameters and data, and configure lower level devices from upper level systems. Courtesy: EtherCAT Technology GroupThe integration of Ethernet with automation can start at the lowest levels and continue up to the process control level for controller-to-controller networking, and then up to the enterprise network level for SCADA and reporting. When properly selected, industrial Ethernet today can be the only bus needed to conduct the business of manufacturing.

An inexpensive yet high-performance Ethernet-based fieldbus technology will enable the process or machine to perform at the highest levels of efficiency. Through increased performance, higher precision, and better diagnostic capabilities, industrial Ethernet will also lower equipment costs, help manufacturers produce better products, and help eliminate waste and power consumption. 

1,000 EtherCAT I/Os in 30 µs

Due to hardware integration in the slave and direct memory access to the network controller in the master, the complete EtherCAT protocol processing takes place within hardware and is fully independent of the run time of protocol stacks, CPU performance, or software implementation. The update time for 1,000 EtherCAT I/Os is only 30 µs, including I/O cycle time. Up to 1,486 bytes of process data can be exchanged in one Ethernet frame, equivalent to almost 12,000 digital inputs and outputs. The transfer of this data quantity takes only 300 µs. One EtherCAT master can communicate with 65,535 slaves in one network.

The EtherCAT fieldbus doesn't require active infrastructure components (such as switches, hubs, and routers), which lowers the cost of EtherCAT compared to traditional fieldbuses. 

Gigabit Ethernet, wireless

At the process control level (controller-to-controller or master-to-master communication), EtherCAT Automation Protocol (EAP) is an EtherCAT-based communication protocol using IP, independent of the physical layer. As a result, communication via gigabit Ethernet or even wireless is possible. EAP enables communication between controllers to exchange process parameters, distribute non-real-time parameters and data, and configure lower level devices from upper level systems. With EAP, the exchange of high-performance data can be managed in a millisecond cycle. If data routing between distributed machines is required, process data can also be transmitted via UPD/IP or TCP/IP.

While the EAP protocol is not real-time, it does streamline process control data exchange.

Upper level enterprise networks traditionally have been rooted in Ethernet communications, so application in this area is natural. Most good controllers and software masters now support OPC UA, for secure exchange of data and settings. Also, these upper level systems may use standard supervisory control and data acquisition (SCADA) and Internet connections for Web-based connectivity for data storage and remote access.

Ethernet can be implemented at all levels of factory automation. EtherCAT can improve fieldbus communications at the device level, as well as at the controller-to-controller, or "process control," level via the EtherCAT Automation Protocol.

- Joey Stubbs, PE, is North American Representative, EtherCAT Technology Group. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering,

ONLINE for July has more information with the online posting of this article.

Key concepts

  • Ethernet can be used as the only network for manufacturing business.
  • Ethernet can reach from the lowest levels of the plant floor through supervisory enterprise networks.
  • EtherCAT protocols can provide Gigabit Ethernet and can be used wirelessly.

Consider this

How many networks do you use? Could consolidation help?

ONLINE extra 

Also see related Control Engineering articles about EtherCAT linked below.

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Learn how to create value with re-use; gain productivity with lean automation and connectivity, and optimize panel design and construction.
Go deep: Automation tackles offshore oil challenges; Ethernet advice; Wireless robotics; Product exclusives; Digital edition exclusives
Lost in the gray scale? How to get effective HMIs; Best practices: Integrate old and new wireless systems; Smart software, networks; Service provider certifications
Fixing PID: Part 2: Tweaking controller strategy; Machine safety networks; Salary survey and career advice; Smart I/O architecture; Product exclusives
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Look at the basics of industrial wireless technologies, wireless concepts, wireless standards, and wireless best practices with Daniel E. Capano of Diversified Technical Services Inc.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.