🏭 Ethernet/IP Raw Packet Debugger & Mock PLC (Python)

Master the CIP protocol without expensive hardware. This project demonstrates how to implement the Ethernet/IP (CIP) protocol using pure Python socket and struct libraries. It includes a Mock PLC Server that runs on localhost, allowing you to test the full Forward Open / Forward Close handshake and Implicit Messaging (UDP I/O) without needing a physical Allen-Bradley or Omron PLC.

[Ethernet/IP Debugger Demo]

🚀 Features

• Zero Dependencies: Written in standard Python. No heavy libraries like pycomm3 or cpppo.
• Full Handshake Implementation:
  • Command 0x65 (Register Session)
  • Command 0x6F (Send RR Data / Forward Open)
  • UDP I/O Data Exchange (Class 1 Implicit Messaging)
• Mock PLC Included: A server script that simulates a CIP-compliant device, listening on TCP 44818 and UDP 2222.

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⚡ Quick Start (How to Run)

Since this simulates a real network connection, you need to run the Server and Client in separate terminals.

Step 1: Start the Mock PLC

Open your first terminal window and run:

python mock_plc_server.py
Output: [Mock PLC] TCP Listening on 44818
Step 2: Start the Client GUI
Open a second terminal window and run:

Bash

python client_gui.py
Step 3: Connect & Test
In the GUI, set Target IP to 127.0.0.1 (Localhost).

Set UDP Port to 2222.

Click ▶ Start I/O Cycle.

You will see the Hex Dump Logs appearing in both windows, simulating a real-time cyclic data exchange between a Controller (Scanner) and an Adapter.

📥 Download Source Code The repository here provides a preview of the architecture.

To get the Complete Source Code (including the GUI implementation, threading logic, and the robust Mock PLC server), you can download the full study kit.

👉 Download the Full Kit on Gumroad ($29):Link

(Includes: client_gui.py, mock_plc_server.py, and a detailed Protocol Guide)

👨‍💻 About the Author Phil Yeh - Senior Automation Engineer

My Gumroad Store (More Engineering Tools)

Keywords: Ethernet/IP, CIP, Industrial Automation, Python, Scada, PLC, Allen-Bradley, Socket Programming, Source Code, Mock Server