Modbus RTU 2-Channel Relay Module RS232 DC3.3-24V Control
Modbus RTU 2-Channel Relay Module RS232 DC3.3-24V Control
Modbus RTU 2-Channel Relay Module with RS232 Serial Control
Take precise control of your automation projects with this compact and reliable Modbus RTU 2IN/2OUT Relay Module. Featuring RS232 serial communication and optocoupler-isolated inputs, this module is engineered for digital signal detection and power switching in industrial, DIY, and embedded system applications. Made in Mainland China.
Key Features
- Dual-Channel I/O: 2 optocoupler-isolated input channels (DC 3.3–24V) for digital signal detection, plus 2 relay output channels for switching loads.
- Wide Power Supply Range: Accepts DC 7–60V supply voltage, making it compatible with a broad range of power sources.
- High-Capacity Relays: Onboard 5V relays rated at 10A/250V AC or 10A/30V DC per channel, with diode discharge protection and up to 100,000 switching cycles.
- Standard Modbus RTU Protocol: Communicates via industry-standard Modbus RTU format over RS232, ensuring easy integration with PLCs, HMIs, and SCADA systems.
- 32-Bit MCU Core: Equipped with a mature and stable 32-bit microcontroller and RS232 level communication chip for fast, reliable operation.
- Configurable Addressing: Device address range of 1–255 (default: 255) and a default baud rate of 9600 bps for straightforward network setup.
- Short Response Time: Designed for fast switching response, ideal for time-sensitive automation tasks.
- Versatile Applications: Suitable for digital quantity detection, power control, relay switching automation, and industrial control panels.
Technical Specifications
| Power Supply Voltage | DC 7–60V |
| Optocoupler Input Signal Range | DC 3.3–24V |
| Communication Interface | RS232 |
| Communication Protocol | Modbus RTU |
| Default Baud Rate | 9600 bps |
| Device Address Range | 1–255 (Default: 255) |
| Relay Rating | 10A / 250V AC; 10A / 30V DC |
| Relay Channels | 2 |
| Input Channels | 2 (Optocoupler Isolated) |
| Relay Lifecycle | 100,000 operations (continuous) |
| MCU | 32-bit |
| Country of Origin | Mainland China |
What's in the Box
- 1× Modbus RTU 2IN/2OUT Relay Module
Notes
- Due to lighting and screen differences, the item's color may vary slightly from the pictures.
- Please allow 1mm–1cm measurement tolerance due to manual measurement.
For guidance on industrial control and electrical safety standards, refer to OSHA Electrical Safety Guidelines.
Frequently Asked Questions
Q: What communication protocol does this Modbus RTU relay module support?
A: This relay module uses the industry-standard Modbus RTU protocol over an RS232 serial interface. It is fully compatible with PLCs, HMIs, computers, and other Modbus master devices. The default baud rate is 9600 bps, and the device address can be configured from 1 to 255.
Q: What voltage levels are supported for the optocoupler inputs?
A: The optocoupler-isolated input channels accept DC 3.3V to 24V signals, making them compatible with a wide range of microcontrollers (including 3.3V and 5V logic systems) and industrial sensors.
Q: What loads can the onboard relays switch?
A: Each of the two onboard relays is rated at 10A / 250V AC or 10A / 30V DC. They include diode discharge protection and are rated for up to 100,000 switching cycles, making them well-suited for controlling lights, motors, solenoids, and other electrical loads.
Q: Can this module be used in an industrial automation or SCADA system?
A: Yes. The module's standard Modbus RTU protocol and RS232 interface make it straightforward to integrate into industrial automation setups, SCADA systems, and PLC-controlled environments for both digital input detection and relay-based power switching.