How EtherCAT helps industrial communications

Industrial networking can help automation applications be more efficient, productive and safer, as explained by Bob Trask, North American Representative EtherCAT Technology Group (ETG) in a Control Engineering interview. Trask worked at Beckhoff Automation as an engineer, software product manager, and systems architect for 20 years. Trask holds a Bachelor of Science in Electrical Engineering from North Carolina State University and has 30 years of experience with automation, motion control, and communication systems. He’s a registered professional engineer.

In the three-part interview, Trask covers:

• Types of automation, controls and instrumentation trends that industrial network organizations are addressing.
• Where EtherCAT is being applied, in what applications and why.
• How EtherCAT and ETG differ from other industrial network and industrial network organization options.
• EtherCAT consistency.
• Ways EtherCAT helps simplify automation designs.
• Industrial network speed versus efficiency.
• EtherCAT functional safety extensions.
• Interoperability and how ETG helps.
• Cybersecurity

Part 1:

Part 2:

Part 3:

Automation trends, applications driving industrial Ethernet

Trask outlined a number of trends influencing industrial networking, including ubiquitous use of physical level Ethernet at all layers of automation systems, centralized motion control, cyclic synchronized modes, industrial safety including how software and drive functions help, PCs for control to simplify adaption of IIoT concepts, openness of internet technologies, cybersecurity concerns and predictive maintenance.

As for applications, EtherCAT is very popular in high end motion systems, synchronized processes and robotics. EtherCAT has advantages because of a very accurate system time through the concept of distributed clocks. Distributed clock capability is built into every EtherCAT device; it only has to be enabled.

EtherCAT applications and implementation

A common mistake is to assume EtherCAT is only used for high end systems, which is not the case. EtherCAT is more often used because of the flexible topology possibilities and not having to use switches, which results in much less cabling. EtherCAT has a reputation with original equipment manufacturers (OEMs) and end users for being significantly easier to implement systems especially regarding installation.

Three areas of domination include huge telescopes, entertainment and semiconductor manufacturing. Three areas of increased use include space hardware manufacturing, medical robotics and humanoid robotics.

EtherCAT and ETG are known for consistency, openness, interoperability, a large focus on device conformance and one-member-one-vote governance.

Network planning and implementation is very straightforward, without switches or addressing and with whatever topology works best for the application. Machine and process modules can be repeated with the same components, same safety setup, same device addresses without IP conflict; drop it in and go.

ETG works closely with the OPC foundation and OPC UA.

EtherCAT communications, functional safety

For safety, communications should be uncomplicated. Safety communications with EtherCAT provide a mathematically assured way of transmitting information. The communications are not making any inference to safety data. Only providing timed and watchdogged communication channels.

Functional safety over Ethernet (FSoE) was planned from the beginning to be an open safety data channel. Safety over EtherCAT set the stage for allowing openness in a historically closed system. The “black channel” approach, which has become popular, is used here. ETG has made a big difference in streamlining conformance and testing for safe status.

EtherCAT diagnostics, more information

Diagnosing problems is one of the most important functions of a modern fieldbus system. EtherCAT provides extensive diagnostic information both at the hardware and software levels. One EtherCAT feature is the ability to detect errors and precisely locate them.

This includes bit errors as well as issues generated by loose connectors. The corresponding error counters are supported by all network subdevices.

It’s functionality that helps users, machine builders and system integrators ensure the robustness of EtherCAT networks and reduce machine downtime to a minimum. Diagnostic routines test the quality of the communication and help easily detect internal errors in subdevices, wrong cabling order, damaged cables or electromagnetic interference.

For more information, see http://ethercat.org, which has many public documents; the most popular is the “ETG.2200 Implementation Guide.”

Edited from video interview and Bob Trask notes by Mark T. Hoske, content manager, Control Engineering, CFE Media and Technology, mhoske@cfemedia.com. EtherCAT Technology Group is a CFE Media and Technology content partner.

KEYWORDS: EtherCAT, industrial Ethernet, industrial network reliability 

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