EtherCAT

showstack / protocols / ethercat

Also called Ethernet for Control Automation Technology.

A real-time industrial Ethernet fieldbus (IEC 61158) offering sub-millisecond, tightly synchronized cyclic control, increasingly used behind the scenes in automated rigging, winch, and scenic-motion systems that need many coordinated servo/VFD axes.

Machinery and motionProprietary, documentedEtherCAT Technology GroupVerified

Stewarded by EtherCAT Technology Group (ETG); originated by Beckhoff Automation.

Control Small, urgent, must arrive

Small messages that either repeat constantly or fire once. Bandwidth is almost never the problem.

What kills it. Latency and loss on the messages that fire once. A repeating level survives a dropped packet; a GO does not.

The four flows, and why the model is worth having →

What goes wrong

Uses standard Ethernet frames (Ethertype 0x88A4) processed 'on the fly' by each slave, so ordinary network switches generally cannot sit inline on a segment without breaking real-time behavior.

Requires a master device driving the cycle timing (a PLC or PC-based controller); it is not a peer-to-peer protocol like DMX or OSC.

What speaks EtherCAT (3)

Product	Direction	Notes
CODESYS CODESYS Group	bidirectional	Supported as a fieldbus.
TwinCAT Beckhoff Automation	bidirectional	The native fieldbus — drives, I/O and sensors on one line, updated every cycle.
Beckhoff CX5140 Embedded PC Beckhoff Automation	bidirectional	Native fieldbus to drives and I/O.

Open source implementations

SOEM (Simple Open EtherCAT Master) — C

Sources

Understand the mechanism

Code on a show Hoists and the safety chain Robots, animatronics and connected things

Something wrong, or missing?

Known gaps on this entry: default_ports, first_published. If you can source one of them, that is a ten minute pull request.

Edit this entry on GitHub — one file, editable in your browser, and your handle goes on it permanently.

Work at EtherCAT Technology Group (ETG); originated by Beckhoff Automation? Confirm or correct this entry — it is free, it stays free, and nothing about it is for sale.