The Allen-Bradley 1756-DNB is a DeviceNet scanner/communication module used in the ControlLogix PLC system from Rockwell Automation. It provides a communication interface between ControlLogix controllers and DeviceNet network devices, enabling data exchange with drives, sensors, motor starters, and distributed I/O.
The module acts as a DeviceNet master (scanner), managing communication with up to 64 nodes on a DeviceNet network.
It is widely used in industrial automation systems such as manufacturing lines, material handling systems, packaging machines, and legacy DeviceNet installations.
Technical Specifications
| Parameter | Details |
|---|---|
| Product Type | DeviceNet Scanner Module |
| Model | 1756-DNB |
| System Compatibility | Allen-Bradley ControlLogix |
| Network Type | DeviceNet |
| Communication Speed | 125 kbps / 250 kbps / 500 kbps |
| Max Nodes | 64 nodes |
| Channels | 1 DeviceNet channel |
| Protocol Function | Scanner (master) |
| Data Transfer | I/O messaging, polling, strobe, cyclic, change-of-state |
| Backplane Interface | ControlLogix chassis backplane |
| Power Consumption | ~3.5–5.8 W |
| DeviceNet Voltage | 11–25 V DC |
| Isolation Voltage | 30 V continuous |
| Installation Type | Chassis slot-mounted module |
| Operating Temperature | 0°C to 60°C |
The 1756-DNB serves as a bridge between ControlLogix and DeviceNet networks, handling input/output data exchange and device status monitoring.
Physical Dimensions & Weight
- Dimensions (H × W × D): 145 mm × 56 mm × 135 mm
- Weight: ~0.3–0.4 kg
The module is designed for standard ControlLogix chassis installation and occupies one slot.
Function in ControlLogix System
The 1756-DNB is used to:
- Act as a DeviceNet master scanner
- Communicate with up to 64 DeviceNet slave devices
- Exchange I/O data with sensors, drives, and actuators
- Perform polling, cyclic, and change-of-state messaging
- Integrate legacy DeviceNet field devices into ControlLogix systems
- Monitor device status and diagnostics
Recommended Related Models
- Allen-Bradley 1756-EN2T Ethernet/IP module
- Allen-Bradley 1756-CNB / CN2 ControlNet modules
- Allen-Bradley 1756-L7x / L8x ControlLogix controllers
- Allen-Bradley 1734 POINT I/O modules
- Allen-Bradley 1794 FLEX I/O systems
