R413D08 8 Channel Module
This Rust project enables communication with an R413D08 8 Channel Module using Modbus RTU/TCP from the command line. It should also work with the R421A08 relay card because it has the same Modbus commands.
Table of Contents
- Hardware Requirements
- Technical Specifications
- Installation & Compilation
- Usage
- Cargo Features
- License
Hardware Requirements
To use this tool, you need:
- One or more R413D08 8 Channel Module.
- One or more 1-8 Channel Relay Board.
- A USB-to-RS485 converter (for RTU mode).

Technical Specifications R4DCB08
| Feature | Details |
|---|---|
| Operating Voltage | 5V DC (5V version) or 6-24V DC (12V version) |
| Operating Current | 10-15mA |
| Baud Rates | 9600 |
| Data Format | N, 8, 1 (No parity, 8 data bits, 1 stop bit) |
| Communication Protocol | Modbus RTU/TCP |
Installation & Compilation
Prerequisites
Ensure you have the following dependencies installed before proceeding:
- Rust and Cargo: Install via rustup
- Git: To clone the repository
Building from Source
- Clone the repository:
- Compile the project:
The compiled binary will be available at: - (Optional) Install the binary system-wide:
This installsrelayto$HOME/.cargo/bin, making it accessible from anywhere.
Usage
View Available Commands
To list all available commands and their options, run:
Read relay status values
For RTU Modbus (RS485) connected devices:
For TCP Modbus connected devices:
Set relay '0' to 'On'
For RTU Modbus:
For TCP Modbus:
Turn Off Relay '3'
For RTU Modbus:
For TCP Modbus:
Cargo Features
| Feature | Purpose | Default |
|---|---|---|
tokio-rtu-sync |
Enable the implementation for the tokio modbus synchronous RTU client | ✅ |
tokio-rtu |
Enable the implementation for the tokio modbus asynchronous RTU client | ✅ |
tokio-tcp-sync |
Enable the implementation for the tokio modbus synchronous TCP client | - |
tokio-tcp |
Enable the implementation for the tokio modbus asynchronous TCP client | - |
bin-dependencies |
Enable all features required by the binary | ✅ |
serde |
Enable the serde framework for protocol structures | - |
License
Licensed under either of:
- Apache License, Version 2.0 (LICENSE-APACHE or Apache)
- MIT License (LICENSE-MIT or MIT)
at your option.