4-channel PWM output module RS485 Modbus RTU isolated

The Waveshare Modbus RTU PWM Output 4CH is an industrial-grade RS485 to PWM output module with four independently configurable PWM channels and comprehensive isolation and protection circuits. All four channels can be independently set in frequency and duty cycle through the Modbus-RTU protocol via the RS485 bus. The outputs are galvanically isolated via high-speed optocouplers, and the module features integrated power supply isolation, resettable fuse, and TVS overvoltage protection.

Recommended Accessories:

• Industrial USB to RS485 Converter

Features:

• Four independently adjustable PWM outputs with individually adjustable frequency and duty cycle via Modbus-RTU protocol per RS485 bus
• High-speed optocoupler isolation on all outputs protects the controller from back effects from the load
• Integrated galvanic isolation (power and signal), resettable fuse, and TVS protection for high operational safety in industrial environments
• Configurable device address (1-255) for cascading multiple modules on a common RS485 bus
• Output high-level voltage switchable via internal jumper – adaptable to the requirements of the connected actuator
• Wide-range power supply 7-36 V DC with onboard voltage regulator – no external auxiliary power supply needed for the isolated side

Application Examples:

• Speed control of DC motors and servo motors via PWM signals from a PLC or industrial PC via RS485
• LED dimmer for industrial or horticultural lighting systems with stepless frequency and brightness control via Modbus
• Frequency generation for testing purposes in electronics development and manufacturing test stands
• Multichannel PWM control of valves, actuators, and fans in automation systems
• Remote control of drives via RS485 network in distributed industrial systems

Documentation:

• Waveshare Wiki - Modbus RTU PWM Output 4CH

Technical Specifications:

• Manufacturer: Waveshare
• Manufacturer SKU: 33921
• Protocol: Modbus RTU
• Interface: RS485
• PWM Channels: 4 (independently configurable)
• Output Isolation: High-speed optocoupler
• Output High Level: Switchable via jumper
• Protection Circuits: Power supply isolation, magnetic isolation, resettable fuse, TVS
• Device Address: 1-255 (configurable)
• Power Supply: 7-36 V DC
• Enclosure: ABS (DIN rail mounting)
• Compatible Platforms: Raspberry Pi (with RS485 HAT), Arduino, PLC, Industrial PC
• Package Dimensions: 135 × 96 × 43 mm
• Gross Weight: 129 g

Package Contents:

• 1× 4-Channel Modbus RTU PWM Relay 4CH