32-Channel 20A Modbus Relay Board RS485 Ethernet DC 12V/24V
32-Channel 20A Modbus Relay Board RS485 Ethernet DC 12V/24V
32-Channel 20A High-Current Modbus Relay Board with RS485 & Ethernet (DC 12V/24V)
Take full control of your automation setup with this professional-grade 32-Channel Modbus Relay Module. Designed for industrial and smart-home applications alike, it supports both RS485 serial communication and Ethernet (TCP/IP) via an RJ45 network port, giving you flexible integration options with PLCs, SCADA systems, and home-automation controllers.
Each relay handles up to 20A of load current, making this board suitable for driving heavy-duty equipment such as LED lamp drivers, motorized curtains, PTZ cameras, and security systems. Built-in TVS anti-surge protection safeguards the board and connected devices from voltage spikes.
Made in Mainland China.
Key Features
- 20A high-current relays — handles demanding loads with ease
- Dual communication interfaces: RS485 serial port & RJ45 Ethernet (TCP/IP)
- Full Modbus RTU support: Old commands (03, 06, 16) & New commands (01, 05, 03, 06, 16)
- Factory-reset via network port — quick recovery without physical access
- TVS anti-surge protection for reliable long-term operation
- Up to 64 devices in parallel under Modbus command mode
- Configurable baud rates: 2400 / 4800 / 9600 / 19200 / 38400 / 57600 / 115200 BPS (default 9600 BPS)
- Adjustable parity: None, Even, or Odd
- Configurable data send/return delay up to 1000ms
- Relay modes: Open, Close, Momentary, Self-locking, Interlock, Delay
Specifications
| Operating Voltage | DC 12V or DC 24V (version dependent) |
| Number of Channels | 32 |
| Maximum Load | 20A/250VAC, 20A/125VAC, 20A/30VDC, 20A/28VDC, 20A/12VDC |
| Drive Current per Relay | 70mA; all 32 relays ON requires ~28.8W power adapter |
| Standby Current (all relays closed) | 15mA |
| Communication | RS485 / Ethernet RJ45 (TCP/IP, Modbus RTU) |
| Default Baud Rate | 9600 BPS |
| PCB Dimensions | 310 × 122 × 25 mm |
| With Din Rail Box | 320 × 132 × 46 mm |
| Weight | 1000g (PCB only) / 1100g (with Din Rail Box) |
| EU LVD Compliance | Low voltage: Below 50VAC or 75VDC |
| Country of Origin | Mainland China |
Typical Applications
- PLC I/O expansion boards
- Smart home & home automation systems
- PTZ and IP camera control
- Security monitoring & access identification systems
- LED lamp driver switching
- Automated curtain and blind control
Package Contents
- 1× 32-Channel 20A Modbus Relay Module
Important Notes
- Colors may appear slightly different due to monitor and lighting variations.
- Please allow ±1–3 cm tolerance due to manual measurement.
- Each relay requires 0.9W drive power. All 32 relays ON simultaneously requires a ≥28.8W power adapter.
For guidance on safe electrical wiring and relay installation, refer to the OSHA Electrical Safety guidelines.
Frequently Asked Questions
Q: What communication protocols does this 32-channel Modbus relay board support?
A: The board supports both RS485 serial (Modbus RTU) and Ethernet TCP/IP communication via an RJ45 network port. It is compatible with Modbus RTU old function codes (03, 06, 16) by default, and new function codes (01, 05, 03, 06, 16) with the M0 configuration. Commands can be entered via a serial HyperTerminal, serial assistant, or Modbus Poll software.
Q: Can I run multiple relay boards on the same RS485 network?
A: Yes. Under Modbus command mode, up to 64 devices can be connected in parallel on the same RS485 bus, making this board ideal for large-scale industrial or home-automation deployments.
Q: What power supply do I need for all 32 relays to operate simultaneously?
A: Each relay consumes approximately 0.9W of drive power (70mA at 12V/24V). With all 32 relays energized at the same time, you will need a power adapter rated at a minimum of 28.8W at your chosen operating voltage (12V or 24V DC).
Q: What is the maximum current each relay can switch?
A: Each relay on this board is rated for a maximum of 20A. It supports load voltages up to 250VAC, 125VAC, 30VDC, 28VDC, and 12VDC, making it suitable for high-current AC and DC applications.
Q: How do I reset the network settings to factory defaults?
A: This board features a built-in network port factory reset function. You can restore factory settings directly through the network interface without needing to physically access or modify the board's hardware.