Allen-Bradley 1756-EN2TR/B EtherNet/IP Communication Module

The Allen-Bradley 1756-EN2TR/B, also cataloged as the 1756-EN2TR EtherNet/IP communication module, operates as a dedicated hardware component for deterministic Ethernet/IP data exchange and redundant controller synchronization within ControlLogix chassis systems. It provides direct physical and protocol-level execution of CIP messaging across dual-port Ethernet networks with redundancy-aware routing.

Configured for redundant controller communication and high-speed CIP data exchange in ControlLogix chassis networks, the Allen-Bradley 1756-EN2TR/B (1756-EN2TR communication module) provides direct physical/electrical execution across EtherNet/IP infrastructures.

Suffix Breakdown & Model Matrix

The base model 1756-EN2TR defines a redundant-capable EtherNet/IP communication architecture for ControlLogix backplane integration. The /B revision reflects updated hardware design with modified Ethernet PHY behavior and improved backplane timing tolerance. No additional functional segmentation is defined beyond revision-level hardware optimization.

Hardware Specifications

ControlLogix Backplane Deterministic Communication & Redundancy Execution Layer

The module interfaces with the ControlLogix backplane using slot-based arbitration and cyclic scan scheduling. EtherNet/IP implicit messaging is executed through CIP objects with deterministic packet timing controlled by chassis scan intervals.

In redundant controller configurations, the module maintains synchronized communication state tables between primary and secondary controllers. Redundancy switchover is governed by chassis health monitoring and backplane state validation. CIP session continuity depends on synchronized connection instance replication across both controllers. Backplane bus communication velocity is constrained by chassis power distribution timing and slot scan allocation. Firmware compatibility must align across redundancy pairs to prevent session desynchronization during failover events.

Frequently Asked Questions (FAQ)

Q: Does the 1756-EN2TR/B maintain CIP connections during redundancy switchover?
A: CIP connections are re-established through the secondary controller after switchover. Session continuity depends on configuration and scan timing.

Q: Can both Ethernet ports operate simultaneously in redundancy mode?
A: Yes. Dual ports support network segmentation or ring/linear topologies with independent traffic handling.

Q: Does backplane loading change in redundant controller configurations?
A: Yes. Redundancy increases cyclic synchronization traffic, raising backplane communication load during active synchronization cycles.

Field Installation Guidelines

Install the module into a powered-down 1756 ControlLogix chassis whenever possible. Ensure full engagement with backplane connectors to maintain stable electrical contact. Maintain consistent firmware versions across redundant controllers and communication modules prior to commissioning. Use shielded Ethernet cabling and ensure proper chassis grounding to reduce EMI coupling on RJ-45 interfaces. Avoid routing Ethernet cables parallel to high-voltage conductors. Verify redundancy configuration, IP addressing, and network segmentation rules before enabling cyclic CIP traffic.