CANopen and EtherCAT share application-layer DNA — EtherCAT’s CoE (CANopen over EtherCAT) reuses the object dictionary and CiA 402 drive profile — which makes migration natural. The difference is bandwidth and determinism: CANopen tops out at 1 Mbit/s on a shared CAN bus, while EtherCAT delivers 100 Mbit/s with “processing on the fly” and sub-microsecond synchronisation.
At a glance
| Criterion | CANopen | EtherCAT |
|---|---|---|
| Physical layer | Classical CAN, ≤1 Mbit/s (CAN FD via CiA 1301) | 100BASE-TX Ethernet, 100 Mbit/s |
| Governing body | CiA | ETG |
| Standards | EN 50325-4 / CiA 301 | IEC 61158, IEC 61784-2 (CPF 12) |
| Typical cycle time | 1–10 ms | <100 µs to ~1 ms |
| Synchronisation | SYNC object | Distributed Clocks, <1 µs jitter |
| Node limit | 127 (practically fewer) | 65,535 per segment |
| Slave hardware | Any CAN controller (often on-MCU) | Dedicated EtherCAT Slave Controller (ESC) |
Engineering detail
CAN’s bus length is propagation-limited (~40 m at 1 Mbit/s, ~500 m at 125 kbit/s), and real-world worst-case latencies of 5–10 ms under load are the practical ceiling for CAN determinism. CANopen FD (CiA 1301) extends payloads to 64 bytes and 2–5 Mbit/s data-phase rates, improving throughput but not turning CAN into a hard-real-time motion bus.
EtherCAT reads and writes each slave “on the fly” as a single frame streams through, so cycle time is bounded by propagation and master processing rather than node count — 1,000 I/O in tens of microseconds is achievable. The cost is a hardware dependency: every EtherCAT slave needs an EtherCAT Slave Controller (ESC) ASIC/FPGA, whereas CANopen runs on the CAN peripheral already present in most MCUs.
When to choose which
CANopen for ≤8 axes, cycle times ≥1–2 ms, harsh/robust environments and the lowest per-node BOM. EtherCAT for high axis counts, sub-millisecond motion, tight synchronisation and large modular machines.
The ISIT-Neperis stacks
ISIT-Neperis provides both CANopen (CiA 301/302) stacks and EtherCAT tooling — including the FSoE Safety-over-EtherCAT stack and an FSoE/EtherCAT network simulation — so you can stay on CAN or move to EtherCAT without changing supplier.