ModbusScanner

A terminal UI tool for scanning and monitoring Modbus devices over RTU (serial) and TCP connections.

Features

• Modbus RTU — connect via serial port with configurable baud rate, parity, stop bits, and data bits
• Modbus TCP — connect via IP/hostname with ping reachability check before connecting
• Function codes — Read Coils (FC 01), Read Holding Registers (FC 03), Read Input Registers (FC 04)
• Data types — 16-bit, 32-bit, and 64-bit integers (signed/unsigned), float, and double
• Byte order — ABCD, DCBA, BADC, CDAB endianness patterns
• Multi-setup — organize connections into named setups, each with multiple slaves and registers
• Persistent config — configurations are saved as JSON files and reloaded on startup
• Batch register entry — add multiple registers at once using ranges and comma-separated lists

Requirements

• Node.js >= 8.17.0

Installation

git clone https://github.com/EmituCom/ModbusScanner.git
cd ModbusScanner
npm install

Usage

npm start

or

node src/main.js

On first launch a welcome screen lets you create a new setup or load a previously saved configuration. Configurations are stored in a configs/ directory in the project root.

Keybindings

| Key | Action | |-----|--------| | r | Refresh — run a new scan | | a | Add a register to the selected slave | | e | Edit the selected item | | d | Delete the selected item | | c | Open the connection manager | | b | Back — return to the welcome screen | | s | Save the current configuration | | x / Space | Toggle scan selection on a register | | Enter / → / l | Expand / drill into selected item | | ← / h | Collapse selected item | | q / Ctrl+C | Quit |

Configuration

Configurations are JSON files saved under configs/. The configs/ directory is excluded from version control via .gitignore so your device addresses and register maps stay local.

License

BSD 3-Clause — see LICENSE