This 4-channel relay module operates via RS-485 using the Modbus RTU protocol. It features high-current relays rated up to 30A at 250V AC or 28V DC and is built for applications requiring reliable switching and communication. The ABS DIN rail-mount case makes it easy to install in industrial environments. The module includes multiple protection circuits such as power isolation, ADI magnetic signal isolation, a resettable fuse, and a TVS diode. It also includes optocoupler isolation to guard against interference from high-voltage circuits, as well as reverse-polarity protection. A dedicated relay driver chip with built-in flyback diode protection ensures consistent switching performance. Power input supports a wide 7–36V DC input range via an onboard voltage regulator. A unibody isolation design provides stable voltage to the isolated terminal without requiring an additional supply. The relay supports flash-on/flash-off operation using command parameters, and each unit can be assigned an address from 1 to 255, allowing multiple devices to share the same RS-485 bus. Three onboard LEDs indicate MCU activity and RS-485 communication status. High-quality screw terminals with covers simplify wiring for high-current loads. Note: Power adapter not included (12V DC Barrel Jack supply recommended). ⚠️Electrical Safety Precautions⚠️ * This product should be operated and used by professional electricians or technical personnel. During use, please ensure electrical safety and take protective measures such as anti-leakage and insulation. * Before installing, maintaining, or replacing relay equipment, make sure to turn off the power and unplug the device. * Do not attempt to dismantle relay equipment to avoid damaging the device or risking electric shock. * Please properly install and place the relay equipment. Avoid using it in damp, overly hot, or flammable environments to prevent safety accidents due to improper installation or use. Features * Configurable device address (1–255); supports cascading on RS-485 bus * Flash-on/flash-off relay control via command with timing support * Wide input voltage range: 7V–36V DC * Integrated power supply isolation; no extra supply needed for isolated terminal * ADI magnetic isolation for reliable signal transmission and low interference * Resettable fuse and TVS diode for surge, overcurrent, and electrostatic protection * Optocoupler isolation to reduce high-voltage interference * Relay driver chip with flyback diode for stable operation * Reverse-polarity protection circuit * Relay contact rating: ≤30A at 250V AC or ≤30A at 28V DC * DIN rail-mount ABS enclosure * Three status LEDs for MCU activity and RS-485 communication Specifications Power Supply DC 7~36V Communication Interface RS485 Communication Baudrate 4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000 Default Communication Format 9600, N, 8, 1 Relay Channels 4 Channels Relay Type High-power relay Contact Form 1NO 1NC Contact Load ≤30A 250V AC or ≤30A 28V DC Modbus Protocol Standard Modbus RTU protocol RS-485 Address Setting 1~255 Indicator STA: MCU indicator, keeps flashing when MCU is working normally TXD: Transmit Data indicator, lights up when transmitting data RXD: Receive Data indicator, lights up when receiving data Resources * Product Wiki Package Contents * 1x 4-Channel Modbus RTU Relay Module with RS-485 Interface Power supply not included. https://elecena.pl/product/28997806/4-channel-modbus-rtu-relay-module-with-rs-485-interface 2025-06-27 https://elecena.pl/product/28997806/4-channel-modbus-rtu-relay-module-with-rs-485-interface 2025-11-29