DIYables ESP32 RS485 Modbus 4 Channel Relay Module
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Quick Overview
The DIYables ESP32 RS485 Modbus Relay Module combines an ESP32-S3 microcontroller with four optocoupler-isolated relay channels, RS485 and USART interfaces, and Modbus RTU protocol support — all in one compact industrial-grade board. With integrated WiFi and Bluetooth from the ESP32-S3, this module enables both wired Modbus communication and wireless remote control for industrial automation and IoT applications.
Programming is simple: the built-in CH340 chip and Type-C interface allow one-click firmware upload via Arduino IDE or PlatformIO without additional hardware. Each relay channel features three output terminals (NO, COM, NC) with optocoupler isolation for strong anti-interference protection, rated 10A at 250VAC/125VAC or 10A at 30VDC/28VDC. The module accepts a wide DC 9-24V power supply.
Ideal for industrial automation, home automation, Modbus RTU master/slave systems, PLC expansion, MQTT-based IoT control, and any application requiring reliable multi-channel relay switching over RS485 or wireless networks.
Key Features
- ESP32-S3 WiFi and Bluetooth — Integrated WiFi and Bluetooth connectivity for wireless remote control, MQTT communication, and IoT data exchange
- RS485 and USART Interfaces — RS485 and USART communication ports with Modbus RTU protocol support for integration into industrial control systems
- 4-Channel Optocoupler Relay — Four optocoupler-isolated relay channels rated 10A 250VAC/125VAC or 10A 30VDC/28VDC with NO, COM, and NC terminals for reliable load switching
- Strong Anti-Interference — Optocoupler input and output isolation protects sensitive components and ensures stable operation in noisy industrial environments
- Type-C with CH340 Chip — Built-in CH340 serial chip and Type-C interface for one-click ESP32-S3 firmware upload via Arduino IDE or PlatformIO
- 9-24V Wide Voltage Input — Accepts DC 9-24V power supply; Type-C port also supports power input for bench use and development
- Signal Indicator LEDs — Power indicator and serial port indicator LEDs for easy status monitoring and debugging
- Wide Compatibility — Compatible with Arduino IDE, PlatformIO, and the full ESP32 development ecosystem
- Versatile Applications — Suitable for industrial automation, home automation, Modbus RTU systems, PLC expansion, and IoT relay control
SPECIFICATION
| Specification | Value |
|---|---|
| Product Type | ESP32 RS485 Modbus Relay Module |
| Channels | 4 |
| ESP32 Module | ESP32-S3 (WiFi + Bluetooth) |
| Serial Port Chip | CH340 |
| Programming Interface | Type-C USB |
| Communication | RS485, USART |
| Protocol | Modbus RTU |
| Relay Load Rating | 10A 250VAC / 10A 125VAC / 10A 30VDC / 10A 28VDC |
| Power Supply | DC 9-24V / Type-C |
| Relay Output | NO, COM, NC per channel |
| Isolation | Optocoupler (input and output) |
| Compatibility | Arduino IDE, PlatformIO, ESP32 ecosystem |
| Applications | Industrial automation, home automation, Modbus RTU, PLC expansion, IoT relay control |
COMPATIBLE HARDWARE
- Computer with Arduino IDE or PlatformIO — Type-C USB for firmware upload and serial monitoring
- RS485 Modbus master devices and PLCs — RS485 A/B terminals for Modbus RTU communication
- Industrial sensors and actuators — direct relay switching via NO/COM/NC output terminals
- Home automation controllers (Home Assistant, Node-RED) — WiFi or Bluetooth wireless relay control
- MQTT brokers and IoT platforms — ESP32 WiFi for publish/subscribe relay control
- DC-powered systems (9-24V) — direct wiring to power input terminals
- Any Modbus RTU master — RS485 interface with configurable slave ID and register addresses
