Wallbox eM4 EVSE Modbus TCP Controller

Production-ready Python controller for monitoring and managing Wallbox eM4 electric vehicle charging stations over Modbus TCP.

Manufacturer's Modbus TCP - Interface Description

Features

• 📊 Real-time monitoring: Read charging status, currents, voltages, power, and energy
• ⚡ Current control: Set maximum charging current (Icmax) with safety validation
• 🖥️ Interactive interface: User-friendly menu-driven interface
• 📟 Command line: Direct CLI commands for automation
• 🔧 Multi-outlet support: Control multiple charging outlets
• 🛡️ Safety validation: Respects installation limits and device constraints

Quick Start

1. Install Dependencies

Windows:

install.bat

Linux/macOS:

./install.sh

Manual installation:

pip install -r requirements.txt

2. Configure Your eM4

Edit config.py and set your eM4's IP address:

EM4_IP = "192.168.1.157"  # Your eM4 IP address

3. Run the Interface

Interactive menu (recommended):

python em4_interface.py

Command line:

# Read all metrics
python em4_modbus.py read

# Set maximum current to 16A
python em4_modbus.py set-icmax 16

# Help
python em4_modbus.py --help

Requirements

• Python: 3.7 or higher
• pymodbus: 3.6.x (automatically installed by setup scripts)
• Network: eM4 must be accessible via TCP/IP

Configuration

All settings are in config.py:

# Network settings
EM4_IP = "192.168.1.157"    # Your eM4 IP address
EM4_PORT = 502              # Modbus TCP port
EM4_UNIT_ID = 0xFF          # Unit identifier

# Current limits
MIN_CURRENT = 6.0           # Minimum current (A)
MAX_CURRENT = 32.0          # Maximum current (A)

# Display settings
DEFAULT_OUTLET = 1          # Default outlet number

Usage Examples

Interactive Interface

============================================================
           Wallbox eM4 EVSE Control Interface
============================================================
📡 Connected to: 192.168.1.157:502
⚡ Current outlet: 1

Available Commands:
1. 📊 Read Current Status & Metrics
2. ⚡ Set Maximum Current (Icmax)
3. 🔌 Change Outlet Number
4. 🌐 Change IP Address
5. 🔄 Reconnect to Device
6. ❓ Show Help
0. 🚪 Exit

Command Line Interface

# Read metrics with default settings
python em4_modbus.py read

# Read specific outlet
python em4_modbus.py --outlet 2 read

# Set current limit
python em4_modbus.py set-icmax 20

# Override IP address
python em4_modbus.py --ip 192.168.1.100 read

Sample Output

Outlet 1  | Status: Charging (0x00C2)
Ic / Icmax / Idefault / Irated: 16.0 A / 20.0 A / 25.0 A / 32.0 A
Phase I [A]: L1=15.8  L2=0.0  L3=0.0
Phase U [V]: L1=231.4 L2=0.0 L3=0.0
Active Power: 3.55 kW
Energy: 12.34 kWh

Understanding the Metrics

Metric	Description
Ic	Current being delivered to EV
Icmax	Your maximum current setting (adjustable)
Idefault	Installation/safety limit (fixed)
Irated	Device maximum capacity (fixed)
Status	Charging state (Ready, Charging, Error, etc.)
Phase I/U	Per-phase current and voltage
Active Power	Current power consumption (kW)
Energy	Total energy delivered (kWh)

Safety Notes

• Current limits: Icmax cannot exceed Idefault (installation limit)
• Minimum current: 6A minimum for safe EV charging
• Installation: Must respect local electrical codes and eM4 installation manual
• Network security: Secure your network connection to the eM4

Troubleshooting

Connection Issues

❌ Connection failed: [Errno 111] Connection refused

• Check IP address in config.py
• Verify eM4 is powered and network accessible
• Check firewall settings
• Ensure Modbus TCP is enabled on eM4

Permission Denied

❌ Error setting Icmax: Requested 25A exceeds installation limit 20A

• Current setting exceeds installation limit (Idefault)
• Reduce requested current or check installation configuration

Import Errors

Error: pymodbus not found

• Run the installation script: install.bat (Windows) or ./install.sh (Linux/macOS)
• Or manually: pip install -r requirements.txt

File Structure

eM4-TCP/
├── em4_modbus.py      # Core Modbus TCP client
├── em4_interface.py   # Interactive menu interface
├── config.py          # Configuration settings
├── requirements.txt   # Python dependencies
├── install.bat        # Windows installation script
├── install.sh         # Linux/macOS installation script
└── README.md          # This file

Technical Details

• Protocol: Modbus TCP (Function codes 0x03 read, 0x10 write)
• Port: 502 (standard Modbus TCP)
• Unit ID: 0xFF (eM4 standard)
• Register format: Big-endian for multi-register values
• Timeout: 3 seconds with automatic retry

License

This project is designed for use with Wallbox eM4 EVSE systems. Ensure compliance with local electrical codes and safety regulations.