Waveshare 8-Channel Industrial Modbus RTU Relay Module (D) – RS485 Interface, Digital Input & 7–36V Power Supply
The Waveshare 8-Channel Industrial Modbus RTU Relay Module (D) is an industrial-grade RS485 relay module designed for reliable remote switching and digital signal monitoring in automation and control systems. It provides 8 relay channels and 8 digital inputs, communicating through the standard Modbus RTU protocol over RS485.
The module operates from a DC 7–36V power supply, while each relay uses a 1NO 1NC contact form and supports a contact load of ≤10A at 250V AC or ≤10A at 30V DC. Its digital inputs accept 5–36V passive or active signals and support both NPN and PNP input configurations through built-in bidirectional optocouplers.
Communication supports baud rates from 4800, 9600, 19200, 38400, 57600, 115200, 128000 to 256000, with 9600, N, 8, 1 as the default format and an RS485 address range of 1–255. The module also provides Normal, Linkage, Toggle and Edge Trigger control modes, making it suitable for industrial automation, PLC control, remote relay switching, digital input monitoring and Modbus-based control systems. Built-in power isolation, magnetic isolation and TVS protection further improve reliability in demanding industrial environments.
Features:
- Cascade several devices on the RS485 bus with configurable device addresses (1-255).
- Features flash-on and flash-off functions; by giving an argument to the command, it is possible to turn on the relay for a while and then close it automatically.
- Onboard unibody power supply separation delivers stable isolated voltage and does not require an additional power source for the isolated terminal.
- Onboard unibody magnetic isolation provides signal isolation, great reliability, robust anti-interference, and low power consumption.
- Onboard resettable fuse and TVS (Transient Voltage Suppressor) effectively suppress surge voltage and transient spike voltage in the circuit, providing over-current/over-voltage proof, lightningproof, and anti-electrostatic.
- Onboard Optocoupler isolation protects the relay from interference from high-voltage circuits.
- Adopts dedicated relay driver chip, with built-in flyback diode protection, for stronger and more steady driving.
- Supports both passive and active digital input, with bidirectional optocoupler separation and a built-in debouncing mechanism. The relay provides digital input linkage control and toggle control.
- Reverse-proof circuit prevents the circuit from being accidently destroyed by an incorrect connection.
- High-quality relay with contact rating of ≤10A at 250VAC/30VDC.
- Rail-mounted ABS plastic enclosure is easy to install and safe to use.
- Multiple LEDs for indicating the MCU state and signal transmission status