rLink 2 Channel RS485 Parallel Relay Module Setup Guide
By Official Hobby Components Online Store | Buy Electronic Kits, Components, Boards, Shields, Modules | Published: 2026-10-25
Category: How-to Guides
Learn how to set up and control the rLink 2 Channel RS485 Parallel Relay Module over a shared RS485 bus using the rLink register-based protocol.
Quick answer
The rLink 2 Channel RS485 Parallel Relay Module uses a register-based protocol over an RS485 bus, allowing you to control multiple modules from one master device. Follow the steps below to wire, address, and send commands.
Why use an RS485 relay module?
RS485 allows multiple devices to share the same two-wire bus over long distances (up to 1200 meters). This makes the rLink 2 Channel Relay Module ideal for industrial or home automation setups where you need to control several relays without running separate wires to each one.
Each module has a unique address, so you can add more modules later without rewiring the bus. The trade-off is that you must configure the address before use, and the protocol requires a master device (like an Arduino or USB-to-RS485 adapter).
Setup steps for the rLink 2 Channel RS485 Relay Module
- 1. Connect the RS485 bus: Wire the A and B terminals of the module to your RS485 master (e.g., an Arduino with an RS485 shield). Use twisted-pair cable for long runs. Connect the master's GND to the module's GND to avoid floating signals. Common mistake: Forgetting the ground connection causes unreliable communication.
- 2. Set the module address: Each module must have a unique address. Refer to the module's datasheet or onboard DIP switches to set the address (usually 1-127). If no DIP switches are present, the address may be set via software commands. Checkpoint: Two modules with the same address will conflict on the bus.
- 3. Power the module: Supply 5V DC to the VCC and GND pins. The relay coils draw about 70-100 mA per channel when active, so ensure your power supply can handle the total load of all modules and relays. Common mistake: Using a weak USB supply may cause the module to reset when both relays engage.
- 4. Send a command to control a relay: Use the rLink register protocol to write to the relay control register. For example, send a byte with the target address, function code, register address, and data (0x01 to turn relay 1 on). Consult the module's protocol documentation for exact byte sequences. Checkpoint: Test with a single relay before scaling up to multiple modules.
Product details
- rLink 2 Channel RS485 / Parallel Relay Module: The rLink 2-Channel Relay Module is an addressable relay module designed for reliable control of loads over an RS485 bus using the rLink register-based protocol. You can control multiple modules from a single master on a shared bus, simplifying wiring and scaling your project.
rLink 2 Channel RS485 / Parallel Relay Module
