Waveshare
4-Channel Industrial Modbus RTU Relay Module – 30A, RS485, LED Indicators, Rail-Mount
· MPN: 30461
The Waveshare Modbus RTU 4-Channel Relay Module provides reliable high-current switching for industrial automation over an RS485 bus. Each of the four SPDT r...
The Waveshare Modbus RTU 4-Channel Relay Module provides reliable high-current switching for industrial automation over an RS485 bus. Each of the four SPDT relays handles loads up to 30A at 250VAC or 28VDC, making it suitable for controlling motors, lighting, HVAC systems, and other heavy-duty equipment.
Communication uses the standard Modbus RTU protocol with configurable device addresses (1–255), allowing multiple modules to be cascaded on a single RS485 bus. The module includes multi-isolation protection with ADI magnetic isolation, resettable fuse, and TVS diode to ensure stable operation in electrically noisy environments.
Key Features
- 30A High-Current Relays – 4× SPDT relays (1NO + 1NC each), rated ≤30A at 250VAC or ≤30A at 28VDC
- Standard Modbus RTU Protocol – Widely supported communication protocol for seamless integration with PLCs, HMIs, and SCADA systems
- Configurable RS485 Addressing – Set unique addresses from 1 to 255 for cascading multiple modules on one bus
- Multi-Isolation Protection – ADI magnetic isolation, resettable fuse, and TVS diode guard against electrical disturbances
- Wide Supply Voltage – Operates from 7V to 36V DC with built-in voltage regulation
- Automatic Flash Control – Program relays to turn on and off for a set period automatically
- LED Status Indicators – Monitor MCU status, data transmission, and reception at a glance
- DIN Rail Mounting – Industrial-grade ABS enclosure with rail-mount design for easy panel installation
Specifications
- Power Supply – 7–36V DC
- Standby Power – ~0.4W (all relays off at 12V)
- Active Power – ~4.9W (all relays on at 12V)
- Communication Interface – RS485
- Baud Rate Options – 4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000 bps
- Default Format – 9600 bps, N, 8, 1
- Relay Channels – 4
- Contact Form – SPDT (1NO + 1NC per channel)
- Contact Rating – ≤30A 250VAC / ≤30A 28VDC
- Device Address Range – 1–255
- Protocol – Modbus RTU
- Dimensions – 145 × 90 × 40mm
- Weight – 278g
Ideal For
- Industrial automation and process control
- Building management and HVAC systems
- Home Assistant and smart home integration
- High-power machinery and lighting control
- PLC and SCADA system expansion
Package Contents
- 1× Modbus RTU 4-Channel Relay Module
Resources
Jargon buster
Plain-language definitions for the technical terms used above.
- baud
- Baud is the signalling rate of a serial connection, often used as the speed setting for UART communication. Matching the baud rate matters because both connected devices must use the same setting for readable data.
- DIN rail
- DIN rail is a standard metal mounting rail used inside industrial electrical cabinets. DIN rail mounting matters because it lets the controller be installed neatly alongside power supplies, relays, and other automation hardware.
- LED
- A light-emitting diode is a small electronic component that lights up when current flows through it in the correct direction. In this kit, LEDs create the flashing effect, so polarity and correct soldering matter for the project to work.
- microcontroller
- A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
- Modbus
- Modbus is an industrial communication protocol used by many meters, sensors, PLCs, and automation devices. Modbus support matters because it can make the controller easier to integrate with existing industrial equipment.
- Modbus RTU
- Modbus RTU is a version of Modbus commonly used over RS485 serial wiring. It matters if you need to connect the controller to industrial sensors, meters, or drives that use serial Modbus rather than Ethernet.
- RS485
- RS485 is a robust wired serial communication standard often used in factories, farms, and buildings where cables may be long or electrically noisy. It matters because it lets this controller connect to industrial sensors, meters, and control equipment over longer distances than typical hobby serial wiring.
- SCADA
- SCADA means Supervisory Control and Data Acquisition, a type of system used to monitor and control industrial processes from computers or control rooms. SCADA compatibility matters if the controller will be part of a larger automation or monitoring setup.
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Robotics & Motion
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