zihluwang
d781d2fadc
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- Split Dockerfile into builder and runtime stages - Put .venv on PATH so pymodbus resolves in the container - Push image to Docker Hub and GHCR with latest and 7-char SHA tags - Use real repo/image names in README
101 lines
2.5 KiB
Markdown
101 lines
2.5 KiB
Markdown
# Modbus Slave Simulator
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A configurable Modbus slave simulator for testing Modbus TCP, RTU, and TLS connections.
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## Features
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- **Multiple Protocols**: TCP, RTU (serial), and TLS support
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- **Configurable Data Store**: Customisable sizes for coils, discrete inputs, holding registers, and input registers
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- **Initial Values**: Set default values for all data types
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- **Device Identity**: Configurable vendor name, product code, model, and version
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- **Docker Support**: Ready-to-use Docker image
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## Installation
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### From Source
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```bash
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git clone https://github.com/zihluwang/modbus-slave
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cd modbus-slave
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pip install -r requirements.txt
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```
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### With Docker
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```bash
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docker pull zihluwang/modbus-slave
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```
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## Usage
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### Command Line
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```bash
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# TCP server (default: 127.0.0.1:5020)
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python main.py
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# Custom port
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python main.py --port 5020
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# RTU mode
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python main.py --type rtu --serial-port /dev/ttyUSB0 --slave-id 2
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# Custom data store sizes
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python main.py --holding-registers-size 1000 --input-registers-size 500
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# Set initial values
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python main.py --holding-registers-default 100 --coils-default true
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```
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### Docker
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```bash
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# Run with defaults
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docker run -p 5020:5020 zihluwang/modbus-slave
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# Run with custom arguments
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docker run -p 5020:5020 zihluwang/modbus-slave --holding-registers-size 1000
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```
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## Command Line Options
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| Option | Description | Default |
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|--------|-------------|---------|
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| `-t, --type` | Server type (tcp, rtu, tls) | tcp |
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| `-h, --host` | TCP bind host | 127.0.0.1 |
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| `-p, --port` | TCP/TLS port | 5020 |
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| `-s, --slave-id` | Modbus slave ID | 1 |
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| `--serial-port` | Serial port (RTU) | /dev/ttyUSB0 |
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| `--baudrate` | Serial baudrate | 9600 |
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| `--coils-size` | Number of coils | 100 |
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| `--holding-registers-size` | Number of holding registers | 100 |
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| `--input-registers-size` | Number of input registers | 100 |
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| `--holding-registers-default` | Default value for holding registers | 0 |
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| `-v, --verbose` | Increase verbosity | - |
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## Modbus Data Model
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| Function Code | Data Type | Access |
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|--------------|-----------|--------|
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| 0x01/0x05/0x0F | Coil | Read/Write |
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| 0x02 | Discrete Input | Read Only |
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| 0x03/0x06/0x10 | Holding Register | Read/Write |
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| 0x04 | Input Register | Read Only |
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## Testing
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Test with `pymodbus` client:
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```python
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from pymodbus.client import ModbusTcpClient
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client = ModbusTcpClient('127.0.0.1', port=5020)
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result = client.read_holding_registers(0, 10)
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print(result.registers)
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client.close()
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```
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## Licence
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See [LICENCE](LICENCE) file.
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