Product description: 16-channel relay module with optoisolation - 10 A / 250 V AC / 30 V DC contacts - 5 V coil - Modbus RS485 - Waveshare 17658
The 16-channel Modbus RTU relay module is an advanced device designed for industrial applications. Its key feature is the ability to control 16 different electrical devices using high-capacity relays up to 10 A , making it suitable for controlling large devices such as motors, pumps, fans, and lighting. The module utilizes the Modbus RTU protocol and an RS485 interface , ensuring easy integration with a wide range of industrial automation systems, such as PLCs (programmable logic controllers), industrial computers, SCADA systems, and platforms like Raspberry Pi or Arduino . By cascading devices on a single RS485 bus , it is possible to control multiple devices without the need for multiple separate communication lines. Built-in magnetic and optoelectronic isolation effectively protects the module from interference and ensures high operational reliability, making it an ideal solution for demanding industrial environments. Additionally, the module is equipped with overvoltage protection (TVS) and a resettable fuse , which effectively protect the device against damage caused by overvoltage or overcurrent.
16 channel relay module with optoisolation - 10 A / 250 V AC / 30 V DC contacts - 5 V coil - Modbus RS485 - Waveshare 17658.
Relay module controlled via RS485 bus, using the Modbus RTU protocol.
Main features of the module
- 16 Relay Channels: Controls multiple high-power devices (up to 10A per channel), including 250V AC and 30V DC devices
- Modbus RTU communication: ensures stable and fast data exchange in industrial systems
- RS485 interface: allows you to connect multiple devices to one bus, which is ideal for extensive industrial installations
- Magnetic and optoelectronic isolation: protects against interference and ensures high operational reliability
- Overvoltage and overcurrent protection: Built-in TVS protection and a resettable fuse prevent damage to the device
- DIN rail mounting: easy installation in control cabinets
- Cascading capability: multiple modules can be connected on a single RS485 bus, increasing installation flexibility
Connecting the module
The module is powered by 5 V DC . Communication with other devices takes place via the RS485 interface. External devices (e.g., motors, pumps, lighting) are connected via the COM and NO terminals. The module allows you to control devices with voltages up to 250 V AC or 30 V DC , and its relays allow for a load of up to 10 A per channel. Connecting multiple modules to a single RS485 bus is possible thanks to the device cascading function, allowing you to control more devices with minimal cabling.
When connecting multiple modules in the system, ensure correct configuration of device addresses (from 1 to 255) and the possible use of RS485 repeaters to maintain stable communication over longer distances.
Module connection diagram.
The design is easy to mount on a 35 mm DIN rail.
Communication and control
The relay module communicates using the Modbus RTU protocol via the RS485 interface. It supports various baud rates, including 4800, 9600, 19200, 38400, 57600, 115200, 128000, 256000 baud, and the ability to address from 1 to 255 devices on a single RS485 bus. Modbus RTU commands can be used to control the module, examples of commands include:
- 01 05 00 00 FF 00 8C 3A - Turn on relay 1
- 01 05 00 00 00 00 CD CA - Relay 1 Off
- 01 01 00 00 00 10 3D C6 - Reading the status of all relays
- 01 05 00 00 55 00 F2 9A - Switching the state of relay 1 (toggle)
The module can be operated using popular tools such as Modbus Poll, the Arduino IDE , as well as dedicated libraries for Raspberry Pi, STM32 , and other platforms. The module also supports full Modbus RTU register and relay functionality , enabling advanced configuration and control.
Technical specifications of the module
- Coil supply voltage: 5 V DC
- Communication interface: RS485
- Baud rate: 4800, 9600, 19200, 3840, 57600, 128000, 256000
- Default communication format: 9600, N, 8, 1
- Number of relays: 16
- Connectors: 1NO 1NC
- Communication protocol: standard Modbus RTU protocol
- RS485 address: 1 to 255
- Maximum relay load: 10 A 250 V AC / 30 V DC
- Protection: power isolation, optical isolation, magnetic isolation, resettable fuse and TVS, overvoltage protection, protection diodes
- LED indicator:
- STA: MCU indicator, flashes when MCU is working normally
- TXD: TX indicator, flashes when sending data
- RXD: RX indicator, flashes when receiving data
- Housing material: ABS
- Mounting: on a 35 mm DIN rail
- Dimensions: 200 x 110.9 x 59.1 mm
Contents of the set
- 1x 16-channel relay module with Modbus RTU protocol
- 1x Power Supply 5V/2A
Elements included in the set.
