64-Ch RS485 Modbus RTU PLC IO Expansion Board NPN 12V 24V
64-Ch RS485 Modbus RTU PLC IO Expansion Board NPN 12V 24V
64DI / 64DO RS485 Modbus RTU PLC IO Expansion Board — NPN Digital Input/Output
Take full control of your automation projects with this high-density 64-channel digital input / 64-channel digital output PLC IO Expansion Board. Featuring optically isolated NPN inputs and Darlington transistor NPN outputs, this board is engineered for reliable, noise-free communication over RS485 using the industry-standard Modbus RTU protocol. Whether you're building a smart home system, managing security cameras, or scaling up industrial automation, this board delivers rock-solid performance with up to 64 devices running in parallel.
Made in Mainland China.
Key Features
- Wide Input Voltage: DC 7–27V (compatible with 9V, 12V, and 24V systems)
- Low Power Draw: Operating current of just 8–50mA
- 64 Optically Isolated NPN Input Ports for interference-free signal reading
- 64 Darlington Transistor NPN Output Ports (ULN2803) — up to 300mA per channel, 1A total maximum load
- 6 Flexible Output Modes: Open, Close, Momentary, Toggle (Self-Locking), Interlocking (Latched), and Delay (0–9,999 seconds; up to 255 seconds via Modbus command)
- RS485 Bus Remote Control: Input ports on one board can remotely trigger output ports on another board across the RS485 network
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Modbus Command Support:
- Modbus Command 1: Function codes 03, 06, 16
- Modbus Command 2: Function codes 01, 02, 03, 05, 06, 15, 16
- Scalable: Up to 64 devices can be connected in parallel on a single Modbus network
- Selectable Baud Rates via Jumper: 1200 / 2400 / 4800 / 9600 (default) / 19200 / 38400 / 57600 / 115200 BPS
- Terminal Connectors: 64P DC3 2.54mm Socket / 66P 2.54mm PIN
Output Mode Glossary
- Open: Output port drives low level
- Close: Output port goes to high impedance (floating)
- Momentary: Output activates (Open), then automatically deactivates (Close) after 0.5 seconds
- Toggle: First command activates output; second command deactivates it
- Latched (Interlocking): Activating one channel automatically deactivates the previously active channel — ideal for mutually exclusive control
- Delay: Output activates, then deactivates after a user-defined delay (0–9,999 seconds; 0–255 seconds in Modbus mode). A Close command cancels the delay immediately.
Specifications at a Glance
| Working Voltage | DC 7–27V (9V / 12V / 24V) |
| Working Current | 8–50mA |
| Digital Inputs | 64 × Optically Isolated NPN |
| Digital Outputs | 64 × Darlington NPN (ULN2803) |
| Max Load per Channel | 300mA |
| Total Max Load | 1A |
| Communication | RS485 / Modbus RTU |
| Default Baud Rate | 9600 BPS |
| Max Parallel Devices | 64 |
| Dimensions (with enclosure) | 296 × 115 × 37mm |
| Weight (with enclosure) | 390g |
| Voltage Safety Class | Low Voltage — below 50Vac or 75Vdc |
Typical Applications
- PLC IO expansion in industrial and commercial automation
- Smart home and home automation systems
- PTZ and IP camera control
- Security monitoring systems
- Access control and identification systems
- LED lamp driver control
- Automated curtain and blind control
- IC testing equipment
- Digital switch input/output detection
Package Contents
- 1× 64DI/64DO RS485 Modbus RTU PLC IO Expansion Board (with enclosure)
Note: Due to lighting and screen variations, actual product color may differ slightly from images. Please allow a 1mm–1cm tolerance due to manual measurement.
For more information on industrial automation standards and safe wiring practices, visit the OSHA Electrical Safety guidelines.
Frequently Asked Questions
Q: What voltages does this PLC IO Expansion Board support?
A: The board operates on a wide DC input voltage range of 7–27V, making it fully compatible with 9V, 12V, and 24V power supplies commonly used in industrial and home automation applications.
Q: How many devices can be networked together on the RS485 Modbus RTU bus?
A: In Modbus command mode, up to 64 of these boards can be connected and operated in parallel on a single RS485 network, giving you a massive 4,096 total input and output channels across one bus.
Q: Can input ports on one board control output ports on a different board?
A: Yes. Via the RS485 bus, the digital input ports on one expansion board can be configured to remotely trigger and control the output ports on another board on the same network — enabling flexible, distributed automation layouts.
Q: What is the maximum load current per output channel?
A: Each individual output channel supports a maximum load current of 300mA. The total combined maximum load current across all channels is 1A, so plan your channel utilization accordingly for larger loads.
Q: How do I change the baud rate on this board?
A: The baud rate is set via onboard jumpers. The default baud rate is 9600 BPS, and you can select from 1200, 2400, 4800, 19200, 38400, 57600, or 115200 BPS to match your host controller or network configuration.