snap7-gui

A Python desktop application for communicating with Siemens PLCs using the S7Comm protocol. Built with PySide6 and python-snap7.

Features

• Variable Configuration: Define PLC variables with name, data type, DB number, and byte/bit offset
• Live Monitoring: Poll and display variable values in real-time
• Read/Write Support: Toggle BOOL values or write numeric values through a simple interface
• Configuration Persistence: Save and load variable configurations to JSON files

Supported Data Types

Type	Description
BOOL	Single bit (with bit offset 0-7)
BYTE	Unsigned 8-bit integer
INT	Signed 16-bit integer
DINT	Signed 32-bit integer
REAL	32-bit floating point

Supported PLCs

• Siemens S7-300
• Siemens S7-400
• Siemens S7-1200
• Siemens S7-1500

Requirements

• Python 3.9+
• PLC with PUT/GET communication enabled

Installation

macOS / Linux

./setup.sh

Windows

setup.bat

The setup script will:

1. Check for Python 3.9+
2. Create a virtual environment in venv/
3. Install all dependencies

Usage

macOS / Linux

./run.sh

Windows

run.bat

Manual Activation

You can also activate the virtual environment manually:

# macOS / Linux
source venv/bin/activate
python main.py

# Windows
venv\Scripts\activate
python main.py

1. Configure Variables: Add PLC variables specifying their data type, DB number, and offset
2. Connect: Enter the PLC IP address, rack, and slot, then click Connect
3. Monitor: View live values as they update from the PLC
4. Write: Toggle BOOL values or click "Write..." to set new values

PLC Configuration (S7-1200/1500)

For S7-1200 and S7-1500 PLCs, you must enable PUT/GET communication in TIA Portal:

1. Open PLC Properties → Protection & Security
2. Set "Full access (no protection)"
3. Check "Permit access with PUT/GET communication from remote partner"

Additionally, for each Data Block you want to access:

1. Right-click the DB → Properties
2. Uncheck "Optimized block access"

Rack and Slot Values

PLC Series	Rack	Slot
S7-1200	0	1
S7-1500	0	1
S7-300/400	0	2

Documentation

• Architecture Overview
• Implementation Phases

License

MIT