The Allen-Bradley 1756-CN2R is a redundant ControlNet communication module used in the ControlLogix PLC system from Rockwell Automation. It provides high-speed, deterministic communication over the ControlNet network and supports dual-channel redundancy for increased system reliability.
This module is designed for mission-critical industrial applications where uninterrupted communication between controllers, I/O devices, and distributed systems is required.
It is widely used in industries such as power generation, oil & gas, petrochemical processing, and large-scale manufacturing systems.
Technical Specifications
| Parameter | Details |
|---|---|
| Product Type | Redundant ControlNet Communication Module |
| Model | 1756-CN2R |
| System Compatibility | Allen-Bradley ControlLogix |
| Network Type | ControlNet |
| Communication Speed | 5 Mbps |
| Channels | Dual ControlNet ports (Redundant) |
| Data Transfer | Scheduled & unscheduled messaging |
| Redundancy Support | Yes (dual network redundancy) |
| Backplane Interface | ControlLogix chassis backplane |
| Power Consumption | ~4–6 W |
| Installation Type | Chassis slot-mounted module |
| Operating Temperature | 0°C to 60°C |
The 1756-CN2R provides enhanced reliability by allowing seamless switchover between redundant ControlNet networks in case of communication failure.
Physical Dimensions & Weight
- Dimensions (H × W × D): 145 mm × 32 mm × 135 mm
- Weight: ~0.3–0.6 kg
The compact design allows installation in standard ControlLogix chassis slots while supporting dual network connections.
Function in ControlLogix System
The 1756-CN2R is used to:
- Provide dual redundant ControlNet communication paths
- Enable deterministic real-time control communication
- Support scheduled and unscheduled data exchange
- Maintain network availability during link failure
- Connect distributed I/O and controllers in ControlNet systems
Recommended Related Models
- Allen-Bradley 1756-CN2 ControlNet module
- Allen-Bradley 1756-EN2T Ethernet communication module
- Allen-Bradley 1756-L7x / L8x ControlLogix controllers
- Allen-Bradley 1756-IB16 digital input module
- Allen-Bradley 1756-OB16E digital output module
