{"title":"4-Channel Industrial Modbus RTU Relay Module – 30A, RS485, LED Indicators, Rail-Mount","handle":"4-channel-industrial-modbus-rtu-relay-module-30a-rs485-led-indicators-rail-mount-ws-30461","url":"/products/4-channel-industrial-modbus-rtu-relay-module-30a-rs485-led-indicators-rail-mount-ws-30461","description":"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.\n\nCommunication 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.\n\nKey Features\n\n\n30A High-Current Relays – 4× SPDT relays (1NO + 1NC each), rated ≤30A at 250VAC or ≤30A at 28VDC\n\nStandard Modbus RTU Protocol – Widely supported communication protocol for seamless integration with PLCs, HMIs, and SCADA systems\n\nConfigurable RS485 Addressing – Set unique addresses from 1 to 255 for cascading multiple modules on one bus\n\nMulti-Isolation Protection – ADI magnetic isolation, resettable fuse, and TVS diode guard against electrical disturbances\n\nWide Supply Voltage – Operates from 7V to 36V DC with built-in voltage regulation\n\nAutomatic Flash Control – Program relays to turn on and off for a set period automatically\n\nLED Status Indicators – Monitor MCU status, data transmission, and reception at a glance\n\nDIN Rail Mounting – Industrial-grade ABS enclosure with rail-mount design for easy panel installation\n\n\nSpecifications\n\n\nPower Supply – 7–36V DC\n\nStandby Power – ~0.4W (all relays off at 12V)\n\nActive Power – ~4.9W (all relays on at 12V)\n\nCommunication Interface – RS485\n\nBaud Rate Options – 4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000 bps\n\nDefault Format – 9600 bps, N, 8, 1\n\nRelay Channels – 4\n\nContact Form – SPDT (1NO + 1NC per channel)\n\nContact Rating – ≤30A 250VAC / ≤30A 28VDC\n\nDevice Address Range – 1–255\n\nProtocol – Modbus RTU\n\nDimensions – 145 × 90 × 40mm\n\nWeight – 278g\n\n\nIdeal For\n\nIndustrial automation and process control\nBuilding management and HVAC systems\nHome Assistant and smart home integration\nHigh-power machinery and lighting control\nPLC and SCADA system expansion\n\n\nPackage Contents\n\n1× Modbus RTU 4-Channel Relay Module\n\n\n\nNote: Power supply and RS485 converter are not included. An RS485-to-USB or RS485-to-TTL adapter is required to communicate with the module from a PC or microcontroller.\n\n\nResources\n\nWaveshare Wiki\nDemo Code (Python, STM32, Arduino, PLC)\nHome Assistant Integration Guide\n","vendor":"Waveshare","product_type":"physical","in_stock":true,"options":[],"variants":[{"id":466,"title":"Default Title","sku":"WS-30461","mpn":"30461","price":48.0,"compare_at_price":0.0,"on_sale":false,"in_stock":true,"available_quantity":103,"option1":"Default Title"}]}