1. This relay is designed for industrial application scenarios, utilizing Modbus RTU protocol control with RS485 signal transmission. It supports multiple devices controlled by a single host and is suitable for industrial automation applications. Featuring an ABS shell and DIN rail mount, it is well-suited for real-world environments. 2. The board is equipped with a stable 8-bit MCU and SP3485 level conversion chip. 3. Wiring instructions: The relay can be assigned an address on the 485 bus ranging from 1 to 255. Corresponding commands can be sent to the relay's address to control the opening and closing of connected circuits. 4. Note: When the relay is energized, the COM terminal connects to the NO terminal and disconnects from the NC terminal, meaning load 1 operates while load 2 is off. When the relay is de-energized or not powered, the COM terminal connects to the NC terminal and disconnects from the NO terminal, meaning load 2 operates while load 1 is off. Power supply voltage: 5–32V (recommended 6V for optimal stability) Communication protocol: Supports standard Modbus RTU protocol Communication interface: RS485 interface with 120Ω terminal resistance dip switch Baud rate: 4800/9600/19200/38400 bps, default 9600 bps, supports power-off configuration retention Output signal: Relay switch signal Due to different production batches, variations in product appearance and printed text may occur; these do not affect functionality. Type: RS485 Modbus Relay PRO 4CH Relay Color: As shown Material: ABS Package Contents: 1 × RS485 Modbus Relay PRO The package includes only the items listed above; other accessories are not included. Note: Lighting conditions and monitor settings may cause slight color differences between the image and the actual item. Measurement error is permitted within +/- 1–3 cm.