The Allen-Bradley 1756-DHRIO is a Data Highway Plus (DH+) and Remote I/O (RIO) communication module used in the ControlLogix PLC system from Rockwell Automation. It provides a communication interface for connecting ControlLogix controllers to legacy industrial networks, including DH+ and Remote I/O systems.
This module is primarily used for migration and integration of legacy Allen-Bradley systems, allowing newer ControlLogix platforms to communicate with older PLCs, drives, and remote I/O devices.
It is widely used in brownfield industrial environments where existing DH+ or RIO infrastructure must be maintained.
Technical Specifications
| Parameter | Details |
|---|---|
| Product Type | Data Highway Plus / Remote I/O Communication Module |
| Model | 1756-DHRIO |
| System Compatibility | Allen-Bradley ControlLogix |
| Network Types | DH+ (Data Highway Plus), Remote I/O (RIO) |
| DH+ Baud Rate | 57.6 kbps / 115.2 kbps |
| RIO Rate | 57.6 kbps |
| Channels | 2 channels (configurable DH+ or RIO) |
| Max Nodes | Up to 32 nodes per channel (DH+) |
| Data Transfer | Peer-to-peer + I/O scanning |
| Backplane Interface | ControlLogix chassis backplane |
| Power Consumption | ~3–5 W |
| Isolation Voltage | 30 V continuous |
| Installation Type | Chassis slot-mounted module |
| Operating Temperature | 0°C to 60°C |
The module allows ControlLogix systems to interface with legacy Allen-Bradley networks such as PLC-5 and SLC systems. (rockwellautomation.com)
Physical Dimensions & Weight
- Dimensions (H × W × D): 145 mm × 32 mm × 135 mm
- Weight: ~0.3–0.5 kg
It is a single-slot ControlLogix module designed for installation in standard chassis systems.
Function in ControlLogix System
The 1756-DHRIO is used to:
- Connect ControlLogix to Data Highway Plus (DH+) networks
- Interface with Remote I/O (RIO) systems
- Enable communication with legacy PLC-5 and SLC controllers
- Support migration from legacy to ControlLogix platforms
- Provide peer-to-peer messaging over DH+ networks
- Maintain compatibility with installed base systems
Recommended Related Models
- Allen-Bradley 1756-CNB / CN2 ControlNet modules
- Allen-Bradley 1756-EN2T Ethernet module
- Allen-Bradley 1756-L7x / L8x ControlLogix controllers
- Allen-Bradley 1771 Remote I/O adapters
- Allen-Bradley PLC-5 and SLC legacy controllers
