| Feature | EtherCAT | Profinet IRT | Sercos III | Ethernet/IP (CIP Sync) | | :--- | :--- | :--- | :--- | :--- | | | <1 µs | 1–5 µs | <1 µs | 10–100 µs | | Min cycle time | 31.25 µs | 31.25 µs | 31.25 µs | 250 µs (typical) | | Topology | Line, ring, star | Line, ring, star | Ring only | Star (requires switches) | | Cable redundancy | Optional (<1 ms) | Yes (MRP) | Yes (native) | Via DLR (ring) | | Slave cost | Low (ESC chip) | Medium (FPGA/ASIC) | Medium | High (stack + ASIC) | | Standard Ethernet | Modified (on-the-fly) | Modified (cut-through) | Modified | Fully standard |
| Feature | Description | | :--- | :--- | | | Each datagram includes a 16-bit counter; each node increments it if operation succeeds – instant mismatch detection | | Link status per port | Each slave’s PHY reports up/down | | Loopback detection | Master can detect ring opens | | Register diagnostics | Each slave exposes error counters, temperature, voltage (if implemented) | | Distributed Clock drift | Monitored automatically | ethercat
But there was a problem. Standard Ethernet was designed for the office, not the factory. | Feature | EtherCAT | Profinet IRT |
| Address Type | Purpose | | :--- | :--- | | | Physical order in the ring (auto-configured) | | Node addressing | Fixed station alias (set in EEPROM) | | Logical addressing | FMMU (Fieldbus Memory Management Unit) maps physical I/O into a 4 GB virtual address space – allows master to read/write scattered I/O with one datagram | - Dewesoft : Because each node acts as
Based on CANopen DS301:
EtherCAT's architecture offers several unique advantages for industrial environments: Dewesofthttps://dewesoft.com What Is EtherCAT Protocol and How Does It Work? - Dewesoft
: Because each node acts as a repeater, the network does not require expensive industrial switches, eliminating the delays they introduce. 2. Performance and Synchronization