2-Channel Ethernet Relay Module Modbus RTU W5500 STM32 LAN
2-Channel Ethernet Relay Module Modbus RTU W5500 STM32 LAN
2-Channel Ethernet Relay Module — Modbus RTU, W5500, STM32, LAN Control
Take full command of your automation projects over a standard LAN connection with this robust 2-Channel Ethernet Relay Module. Built around the reliable STM32F103C6T6 32-bit MCU and the W5500 full-hardware TCP/IP Ethernet chip, this board delivers stable, low-latency network control using the industry-standard Modbus RTU protocol. Whether you're building a smart home, industrial automation rig, or a custom IoT controller, this module offers the flexibility and durability to get the job done. Made in Mainland China.
Key Features
- STM32F103C6T6 MCU: Mature, stable 32-bit microcontroller for dependable performance.
- W5500 Ethernet Chip: Full hardware TCP/IP protocol stack supporting 10/100 Mbps speeds.
- Modbus RTU Protocol: Industry-standard communication for seamless integration with PLCs, HMIs, and SCADA systems.
- TCP Server Mode: Operates as a TCP Server; supports DHCP IP assignment on port 5000.
- IP Visibility via Serial Port: View the module's IP address through the UART interface at 115200 baud.
- 2 x Relay Channels: Onboard 5V relays rated 10A/250VAC and 10A/30VDC — rated for up to 100,000 switching cycles each.
- Flexible Output Modes: Supports manual, flashing ON/OFF, and flashing OFF modes; flashing interval base is 0.1 seconds, up to 6,553.5 seconds maximum.
- Device Addressing: Configurable address range 1–255 (default: 255) with power-off memory retention.
- Diode Discharge Protection: Built-in protection circuitry for each relay channel.
- Onboard Indicator Lights: Power and relay-status LEDs for at-a-glance monitoring.
- MCU Reset Button: Conveniently located onboard reset for quick restarts.
- Secondary Development Ready: Reserved UART serial port and SWD programming port for custom firmware.
- Wide Power Input: DC 7–36V via 5.08mm terminal block; includes input reverse-polarity protection.
Specifications
| MCU | STM32F103C6T6 (32-bit) |
| Ethernet Chip | W5500 (Full Hardware TCP/IP) |
| Network Speed | 10/100 Mbps |
| Protocol | Modbus RTU over TCP |
| TCP Mode | Server (Port 5000, DHCP supported) |
| UART Baud Rate | 115200 |
| Relay Channels | 2 |
| Relay Rating | 10A/250VAC, 10A/30VDC |
| Relay Endurance | 100,000 switching cycles |
| Power Supply | DC 7–36V (5.08mm terminal) |
| Voltage Safety | Below 50VAC / 75VDC (LVD compliant) |
| Hazardous Chemicals | None |
| Country of Origin | Made in Mainland China |
What's in the Box?
- 1× 2-Channel Ethernet Relay Module
Notes
- Due to monitor and lighting variations, actual product color may differ slightly from images.
- Please allow 1mm–1cm tolerance due to manual measurement.
For more information on industrial automation networking standards, refer to the NIST Engineering Laboratory. For electrical safety guidelines, visit OSHA Electrical Safety.
Frequently Asked Questions
Q: What communication protocol does this Ethernet relay module support?
A: This module supports the standard Modbus RTU protocol over TCP/IP, making it fully compatible with PLCs, SCADA systems, HMIs, and other industrial automation equipment that use Modbus for device communication.
Q: What is the power supply range for this relay module?
A: The module accepts a wide input voltage of DC 7–36V via a 5.08mm terminal block. It also features built-in reverse-polarity protection, so accidental reverse wiring won't damage the board.
Q: Can I use this module for custom firmware development?
A: Yes. The board includes reserved UART serial port and SWD program burning port interfaces, supporting full secondary development for custom applications built on the STM32 platform.
Q: How many relay channels are available, and what are the ratings?
A: There are 2 onboard relay channels, each rated at 10A/250VAC and 10A/30VDC. Each relay is designed to withstand up to 100,000 switching cycles, with diode discharge protection for extended service life.
Q: Does the module support DHCP for automatic IP assignment?
A: Yes. When operating in TCP Server mode on port 5000, the module supports DHCP for automatic IP address assignment. The assigned IP address can be viewed through the onboard UART serial port at a baud rate of 115200.