Industrial Networking Basics

Fieldbus vs Industrial Ethernet

Traditional fieldbuses (PROFIBUS, DeviceNet) are being replaced by Industrial Ethernet protocols that carry both real-time control traffic and IT data on shared infrastructure.

EtherCAT uses frame processing on the fly for sub-millisecond cycle times. PROFINET offers IRT for isochronous motion. Modbus TCP suits simpler I/O and energy monitoring.

Network Topology

Line topology is standard for EtherCAT — each node forwards frames. Star topology suits PROFINET with managed switches. Always separate OT control network from corporate IT using VLANs or physical segmentation.

• Use industrial-rated Cat5e/Cat6 cables with solid conductors for fixed installs
• Maximum cable segment: 100 m for copper Ethernet
• Document IP address plan before commissioning
• Enable switch port mirroring only for diagnostics — not in production

Commissioning Checklist

Verify link speed and duplex on all ports. Scan the network for duplicate IP addresses. Test cycle time under full I/O load before connecting motion axes.