Modular Relay Module 4R-D7 Modbus RTU, 4-channel relay interface (No name)

The Modular Relay Module 4R-D7 Modbus RTU is a 4-channel relay interface designed for integration into Modbus RTU networks. It provides four independent relay outputs controllable over a serial Modbus RTU connection, enabling remote switching and status monitoring of connected loads. The module is suitable for building automation, industrial control panels and other systems that require reliable relay outputs accessible via Modbus RTU.

Advantages

The module offers four relay channels in a compact modular form factor, allowing centralized control of multiple loads via a single Modbus RTU link. Serial Modbus RTU communication simplifies integration with PLCs, SCADA systems and other Modbus masters while enabling remote status reads and control commands. Its straightforward interface reduces wiring complexity and supports common applications such as lighting, pumps and actuator control where relay outputs are appropriate.

Suitable for

• Building automation: control of lighting, ventilation and HVAC peripheral devices
• Industrial control panels: switching of machines, indicators and auxiliary equipment
• Remote switching: pumps, valves and actuators that require on/off control via Modbus RTU
• Integration with PLCs and SCADA systems requiring relay outputs

Key specifications

• Number of relay channels: 4 independent outputs
• Communication protocol: Modbus RTU (serial)
• Interface type: relay outputs for on/off switching
• Form factor: modular relay module for panel or DIN-rail mounting environments (module style)

How to use

Install the 4R-D7 module in the control panel or on the intended rail or mounting point and connect the relay outputs to the loads using appropriate gauge wiring and protective devices. Connect the serial Modbus RTU bus lines (A/B or TX/RX and ground as applicable) to the Modbus master device and configure the communication parameters (baud rate, parity, stop bits and device address) on both the module and the master. Use Modbus RTU function codes supported by the system to read relay status and to issue on/off commands for each channel. Verify wiring polarity and protective fusing before energizing the circuit.

Usage recommendations

Use the module with compatible Modbus RTU masters and follow electrical safety standards: select relays and wiring rated for the connected load, add external protection (fuses or breakers) where required, and ensure proper grounding and isolation between control and power circuits.