profinet-py

A Python library for PROFINET IO communication, acting as an IO-Controller.

Features

• DCP Discovery & Configuration: Find devices, set IP/name, signal LEDs, factory reset with full SET response validation
• DCE/RPC Communication: Establish Application Relationships (AR) and perform acyclic read/write via slot/subslot/index
• I&M Records: Read/write Identification & Maintenance data (IM0-IM5)
• Cyclic I/O: Real-time periodic data exchange (RT_CLASS_1) with state machine, double-buffered IO, cycle counter tracking, watchdog fault detection, and graceful shutdown
• Alarm Handling: Background alarm listener per IEC 61158-6-10
• Diagnosis Parsing: Channel, extended channel, and qualified channel diagnosis decoding
• Vendor Registry: 2100+ PROFINET vendor IDs with name lookup
• Declarative Parsing: Binary protocol parsing via construct library
• Cross-Platform: Linux (AF_PACKET), Windows (Npcap)
• High-level API: ProfinetDevice class and scan() for quick device interaction

Requirements

• Python 3.10+
• Administrator/root privileges (for raw Ethernet access)
• construct>=2.10

Platform-specific

Installation

pip install profinet-py

From source:

git clone https://github.com/f0rw4rd/profinet-py.git
cd profinet-py
pip install -e ".[dev]"

Usage

import profinet

# Discover all PROFINET devices on the network
for device in profinet.scan("eth0", timeout=5):
    print(f"Found: {device.name} at {device.ip} ({device.mac})")

On Windows, use the adapter's friendly name:

for device in profinet.scan("Ethernet 3", timeout=5):
    print(f"Found: {device.name} at {device.ip}")

Low-level DCP + RPC

from profinet.util import ethernet_socket, get_mac
from profinet.dcp import send_discover, read_response
from profinet.rpc import RPCCon

# Create raw socket on interface
sock = ethernet_socket("eth0")
src_mac = get_mac("eth0")

# Discover PROFINET devices
xid = send_discover(sock, src_mac)
responses = read_response(sock, src_mac, timeout_sec=5, expected_xid=xid)

sock.close()

DCP discovery and GET accept incorrect transaction IDs (XIDs) with a warning by default for compatibility with devices that echo wrong or zero XIDs. This can accept stale replies. Pass strict_xid=True to read_response() (with expected_xid), get_param(), or get_station_info() to reject mismatches. CLI and high-level device discovery use lenient defaults.

CLI

# Discover devices
profinet -i eth0 discover

# Read I&M0 from device
profinet -i eth0 read-inm0 device-name

# Read raw record
profinet -i eth0 read device-name --slot 0 --subslot 1 --index 0xAFF0

# Cyclic IO monitoring (default 32ms cycle)
profinet -i eth0 cyclic device-name --gsdml device.xml

# Custom cycle time
profinet -i eth0 cyclic device-name --gsdml device.xml --cycle-ms 16

# Exclude zero-I/O submodules (device interoperability workaround)
profinet -i eth0 cyclic device-name --gsdml device.xml --exclude-zero-io-submodules

Support

If you find this project useful, consider supporting development:

License

Dual-licensed under GPL-3.0 and a commercial license.

Free for open source use under GPL-3.0. If you want to use profinet-py in proprietary products without GPL obligations, a commercial license is available — see LICENSE-COMMERCIAL.md for details.

References

• PROFINET Specification
• Wireshark PROFINET/IO
• construct library

Trademarks

All marks belong to their owners; used nominatively to describe interoperability; no endorsement implied.