PROFINET

PROFINET is the open Industrial Ethernet protocol maintained by PI (PROFIBUS & PROFINET International) and most strongly associated with the Siemens ecosystem.

Overview

• Standard Ethernet (100 Mb / 1 Gb).
• Uses raw Ethernet frames (EtherType 0x8892) for cyclic data.
• TCP/UDP for parameterization, alarms, and acyclic.
• Devices identified by station name (NameOfStation), not IP — IP can be assigned by the controller via DCP.

Conformance Classes

• CC-A — basic RT, standard switches OK; typical jitter ~10 ms.
• CC-B — RT + diagnostics, managed switches required.
• CC-C — Isochronous Real-Time (IRT); deterministic, <1 ms cycle, needs PROFINET-capable switches.
• PROFINET-CC-D adds TSN extensions.

Device Configuration

• GSDML file describes the device (modules, submodules, parameters).
• Import into TIA Portal; drop the device into the topology / network.
• Assign IP and PROFINET name (right-click → Assign device name).
• Set update time per slot (typ. 1–32 ms).
• Configure shared device / shared inputs where multiple IO controllers need access.

Topology & MRP

• Star, line, tree, ring.
• MRP (Media Redundancy Protocol) — ring with sub-200 ms failover (default).
• MRPD — MRP for IRT, sub-1 ms.
• Use PROFINET-capable managed switches (Scalance XB/XC/XR, Hirschmann, etc.).
• Wiring: green PROFINET cable (Cat 5e equivalent, 4-pair shielded), max 100 m between nodes.

PROFIsafe

• Black-channel approach — safety frames over standard PROFINET.
• SIL3 / PLe certified.
• Uses F-CPU and F-I/O modules.
• Each safety connection has a unique F_Source_Address / F_Destination_Address.

Troubleshooting

• Use TIA Portal > Online & diagnostics to read device status, alarms, port stats.
• Wireshark with PROFINET dissector.
• Check that device name & IP match what the controller expects.
• BF / SF LEDs on Siemens modules indicate bus / system faults.
• Common issue: wrong cable type (use rated PROFINET cable; not patch cable in machinery vibration).