CODESYS is a fieldbus master for EtherCAT, PROFINET, EtherNet/IP, Modbus and more. EtherCAT is the clever one: instead of addressing each device separately, a single frame flies down the line and every slave reads its outputs and writes its inputs as the frame passes through — "processing on the fly." Watch one frame service the whole network in a single lap.
The master sends one EtherCAT frame down the chain. As it reaches each slave, that slave grabs its piece and inserts its inputs — in hardware, in nanoseconds, without stopping. The frame loops back to the master with all the data, every cycle. Run it and watch the single frame read/write all four slaves in one trip.
That's why EtherCAT is so fast: there's no per-device round trip — one frame, one lap, the whole network's I/O exchanged with microsecond precision. You add slaves by importing their ESI description files into the device tree (Track 05), just like a GSDML for PROFINET.
⚡ EtherCAT — the fast, deterministic favourite. On-the-fly processing, sub-millisecond cycles, distributed clocks for sync. ESI device files.
🌐 PROFINET & EtherNet/IP — talk to Siemens/Rockwell-world devices. GSDML/EDS files, cyclic provider-consumer exchange.
🔢 Modbus TCP/RTU — the universal fallback (see the Schneider academy). Great for meters, sensors and legacy gear.
🚐 CANopen / J1939 — for CAN-based drives, vehicles and mobile machinery. All configured in the same device tree.
What makes EtherCAT exchange a whole network's I/O so much faster than polling each device?