32-Ch RS485 Modbus RTU PLC IO Expansion Board | DIN35 Rail
32-Ch RS485 Modbus RTU PLC IO Expansion Board | DIN35 Rail
32-Channel RS485 Modbus RTU PLC IO Expansion Board with DIN35 Rail Box
Take full control of your automation projects with this versatile 32-Channel RS485 Modbus RTU PLC IO Expansion Board. Built around the reliable ULN2803A Darlington Transistor array, this controller delivers precise, multi-channel output switching for industrial and maker automation systems. Housed in a flame-retardant UM72 DIN35 guide rail enclosure, it installs cleanly on standard DIN35 or C45 rails — ideal for control panels, automation cabinets, and prototyping setups.
Whether you're expanding an existing PLC system, building a custom automation controller, or running smart switching sequences, this board gives you 32 independently controlled output channels with a wide operating voltage range and full Modbus RTU protocol support.
Key Features
- Wide Input Voltage: DC 6.5–30V (compatible with 9V, 12V, and 24V systems)
- 32 Output Channels driven by ULN2803A Darlington transistors, up to 300mA per channel
- 6 Flexible Control Commands: Open, Close, Momentary, Self-locking, Interlock, and Delay (max 255-second delay)
- RS485 Communication with full Modbus RTU protocol support — up to 64 devices in parallel
- Configurable Baud Rate: Default 9600 BPS; adjustable to 1200, 2400, 4800, 9600, or 19200 BPS via command
- Low Standby Current: 5mA (all channels closed); 57mA (all channels open)
- DIN35 & C45 Rail Mount: UM72 flame-retardant V0-grade enclosure for secure panel installation
- Modbus Commands can be entered via serial HyperTerminal or Modbus Poll software
Specifications
| Working Voltage | DC 6.5–30V (9V / 12V / 24V) |
| Standby Current | 5mA (all off) / 57mA (all on) |
| Max Channel Load | 300mA per channel |
| Communication Protocol | RS485, Modbus RTU |
| Default Baud Rate | 9600 BPS |
| Max Parallel Devices | 64 |
| PCB Board Size | 100 × 72 × 20 mm |
| With DIN Rail Box Size | 120 × 88 × 42 mm |
| PCB Weight | 65g |
| With DIN Rail Box Weight | 144g |
| Rail Box Model | UM72 — DIN35 / C45 compatible |
| Insulation Grade | Flame-retardant V0 |
| Country of Origin | Made in China |
What's in the Box?
- 1× DC 12V 32-Channel DIN35 Rail Box RS485 Modbus RTU Controller Board
Helpful Resources
For general electrical safety guidelines relating to low-voltage control equipment, refer to the OSHA Electrical Safety resource.
Note: Due to lighting and monitor differences, the actual color may vary slightly from product images. Please allow ±1–3 cm variance due to manual measurement.
Frequently Asked Questions
Q: What voltage does the 32-channel RS485 Modbus RTU controller board support?
A: The board operates on a wide DC input range of 6.5V to 30V, making it compatible with common supply voltages including 9V, 12V, and 24V systems.
Q: How many devices can be connected in parallel using Modbus RTU over RS485?
A: In Modbus RTU command mode, the controller supports up to 64 devices connected in parallel on a single RS485 bus, making it highly scalable for larger automation systems.
Q: What control commands does this PLC IO expansion board support?
A: The board supports 6 command types: Open, Close, Momentary, Self-locking, Interlock, and Delay. The Delay command supports a maximum delay duration of 255 seconds per channel.
Q: Can I modify the baud rate on this RS485 controller?
A: Yes. The default baud rate is 9600 BPS and can be changed via software command to 1200, 2400, 4800, 9600, or 19200 BPS to match your communication requirements.
Q: What software can I use to send Modbus RTU commands to this board?
A: Modbus RTU commands can be sent using any serial terminal application such as a Serial HyperTerminal or the popular "Modbus Poll" utility, giving you flexible integration options.