In the demanding world of high-speed control, conventional protocols often work like a mail carrier stopping at every house on a street. A frame is sent to a node, a response is awaited, and only then does communication move on to the next device. This 'one frame per node' approach is inherently slower, creating overhead and latency that can struggle to keep pace with modern real-time requirements.
According to Supriya Suhale, category manager – Connectivity at Beckhoff Automation, EtherCAT delivers a fundamental performance breakthrough, with its strength coming from a unique functional principle that treats the network as a single, cohesive machine.
"Rather than relying on individual node-to-node handshaking, EtherCAT uses a 'process on-the-fly' methodology, allowing data to be handled efficiently as frames pass through each device," Suhale explained.
"Instead of every node receiving, interpreting, and copying data, a single Ethernet frame travels through the entire network. Each slave device reads its data and inserts its own input, while the telegram passes through at lightning speed."
Suhale said that this is where EtherCAT delivers a level of efficiency that traditional networks often cannot match.
"With cycle times of ≤100 μs and jitter levels below 1 μs, it’s undeniably impressive. It’s proven, widely adopted, and has a track record of delivering the kind of real-time performance that modern machines demand," she added.
"While this creates a bandwidth utilisation ratio of over 90 per cent, the real-world advantage is that this efficiency leaves massive room for the system to handle errors and diagnostics without missing a beat. EtherCAT’s speed is impressive in ideal conditions, but its real advantage is in how quickly it helps teams recover when things aren’t ideal."
Instant diagnostics
In conventional fieldbus systems, a bit error often propagates along the entire line, leaving you searching for a needle in a haystack. Suhale unpacks how EtherCAT handles this differently:
- Error Localisation: Every node checks the frame for errors using a 32-bit CRC checksum. If a bit error is detected, the slave increments an error counter and informs subsequent nodes.
- Pinpointing the Fault: The master can analyse these counters to tell you exactly where the disturbance occurred, for example, specifying a fault between node 58 and 59.
- Working Counter (WKC): Each datagram contains a 'health check' called the Working Counter. If the returned value doesn't match the expectation, the master knows instantly that data consistency has been compromised and can discard the faulty frame.
High availability and quick recovery
The true test of a system is a cable break. In many Industrial Ethernet setups, a broken cable means a dead segment. EtherCAT transforms this from disaster to minor hiccup through Cable Redundancy:
- Logical Ring Topology: By using a second Ethernet port on the master, a line topology is extended into a ring.
- Ultra-Fast Re-routing: If a cable breaks, the redundancy case is detected and resolved with a recovery time of less than 15 microseconds.
- Uninterrupted Control: This recovery is so fast that, at most, only a single communication cycle is disrupted. Even high-speed motion applications continue to work smoothly while the hardware issue is addressed.
Flexible maintenance with Hot Connect
EtherCAT’s quick recovery functionality also applies to human intervention. Its Hot Connect feature allows you to disconnect or reconnect segments while the rest of the network remains in an operational state.
"Using hardware-integrated EtherCAT Slave Controllers (ESC), ports are automatically closed if a downstream device is missing, completing the logical loop," explained Suhale.
"When a segment is plugged back in, the system uses unique Device IDs (set via physical switches or stored aliases) to identify the returning nodes independently of their physical position. This allows for ’Hot Swapping’ of devices without needing to restart the entire machine."
Managing EtherCAT revisions
Besides making maintenance easier, EtherCAT also makes system upgrades more efficient. Stability in an EtherCAT system is governed by ESI (EtherCAT Slave Information) XML files. These files are the identity profiles of the slave, defining the process image (PDOs) and communication settings.
Crucially, these descriptions are stored in the EEPROM of the slave hardware, allowing the Master to perform an 'Online Scan' and identify the device even without an offline configuration file.
System longevity is protected by the downward compatibility rule: Devicerevisioninthesystem≥devicerevisionintheconfiguration.
This allows you to replace a faulty revision -1018 terminal with a newer -1019 version without touching the software. However, the documentation provides a strict primary directive: "Never touch a running system. An update of firmware or revision should be carried out only if there is a justified cause to do so."
As Suhale highlighted, if an update is required, the order in which it’s implemented is paramount: update the Firmware first, then the XML/ESI in the EEPROM, which ensures the firmware is capable of supporting the updated communication queries and device functions defined in the new ESI.
“EtherCAT is fast but that’s not the point,” concluded Suhale. “Its real value lies in its robustness. By shifting time-critical functions into hardware and providing nanosecond-accurate diagnostics, EtherCAT ensures that when a bit is flipped or a cable trips, your recovery is as fast as your cycle time.”
EtherCAT Seminar Roadshow
EtherCAT is one of the most widely discussed industrial networks in automation, supported by the EtherCAT Technology Group (ETG), with over 8500 member companies across more than 78 countries.
For machine builders, system integrators, commissioning engineers or control engineers working with EtherCAT (or considering a shift), the ETG EtherCAT Seminar Series Australia 2026 presents a valuable opportunity to hear the technical details directly from the source and ask practical questions relevant to specific projects.
The seminars are taking place in:
- Perth (19 February)
- Melbourne (24 February)
- Sydney (25 February)
- Brisbane (26 February)
The EtherCAT Seminar Series Australia 2026 is sponsored by Balluff Australia, Beckhoff Australia, Kübler Group, and SMC Australia.
Registrations are now open and the seminars are free to attend, but seats are limited.
