Allen-Bradley 1756-DNB/E DeviceNet Communication Module

The Allen-Bradley 1756-DNB/E, also cataloged as the 1756-DNB/E DeviceNet Communication Module, operates as a dedicated hardware component for real-time DeviceNet network integration within ControlLogix backplane systems. It provides direct electrical execution of cyclic I/O data exchange between Logix5000 controllers and distributed DeviceNet nodes through the 1756 chassis backplane architecture.

Suffix Breakdown & Model Matrix

• 1756: ControlLogix chassis platform identifier

• DNB: DeviceNet Bridge communication function

• /E: Revision identifier for hardware/firmware iteration

Hardware Specifications

ControlLogix Backplane Bus and Deterministic Network Behavior

The module interfaces through the ControlLogix backplane, operating within deterministic scan cycles defined by Profinet / EtherNet/IP deterministic networks architecture. I/O density scaling is managed through chassis slot addressing, while firmware flash compatibility ensures alignment with Logix5000 system revisions. Backplane bus communication velocity Licences regulate data exchange timing between controller task execution and DeviceNet cyclic frames. The module maintains isolated execution paths between backplane memory mapping and external DeviceNet traffic.

Frequently Asked Questions (FAQ)

Q: Can the 1756-DNB/E be hot-swapped during runtime operation?
A: Yes, but removal triggers network disruption on DeviceNet nodes until module reinitialization completes and scan rebind occurs.

Q: What is the backplane current limitation per ControlLogix slot?
A: The module draws approximately 800 mA at 5 VDC; total chassis power budget must accommodate cumulative slot load.

Q: Does firmware revision affect DeviceNet node compatibility?
A: Yes, firmware mismatch can alter node mapping tables and cyclic I/O scheduling behavior across the network.

Field Installation Guidelines

• Insert module into a powered-down or chassis-supported hot-swap compatible ControlLogix slot.

• Ensure DeviceNet trunk is terminated with correct impedance resistors at both ends.

• Maintain shield continuity across all DeviceNet cable segments.

• Verify 5-pin Phoenix connector pinout alignment before energizing network.

• Avoid routing DeviceNet cable parallel to high-voltage conductors to reduce induced noise coupling.

• Confirm chassis backplane seating depth is fully engaged before commissioning.