Allen-Bradley 1756-EN2T/D EtherNet/IP Bridge Module

The Allen-Bradley 1756-EN2T/D, also cataloged as the 1756-EN2T EtherNet/IP Bridge Module, operates as a dedicated hardware component for deterministic network communication bridging within the ControlLogix platform and EtherNet/IP networks. It provides direct physical and protocol-level execution of CIP-based data exchange between ControlLogix controllers and distributed industrial Ethernet nodes.

Configured for high-speed controller-to-network communication in ControlLogix chassis systems, the Allen-Bradley 1756-EN2T/D (1756-EN2T EtherNet/IP Bridge Module) provides direct physical/electrical execution across EtherNet/IP networks.

Suffix Breakdown & Model Matrix

No validated manufacturer-defined functional segmentation is published for the /D suffix beyond hardware revision tracking. The revision indicates incremental hardware-level changes within the same functional module family (1756-EN2T series), without architectural redesign.

Hardware Specifications

ControlLogix Backplane & EtherNet/IP Deterministic Communication Behavior

The module integrates into the 1756 ControlLogix backplane using cyclic data exchange mechanisms synchronized with chassis scan cycles. Backplane bus communication velocity is constrained by chassis scheduling and slot arbitration timing. EtherNet/IP cyclic traffic uses implicit messaging over TCP/UDP CIP objects. Firmware flash compatibility is dependent on controller and chassis revision alignment, requiring version consistency across network nodes. I/O density scaling is governed by connection instance allocation per CIP session, limiting total active multicast and unicast paths under system load. The revision /D implements updated Ethernet PHY handling to maintain signal integrity under sustained packet throughput conditions.

Frequently Asked Questions (FAQ)

Q: Does the 1756-EN2T/D support hot-swap removal under power?
A: Yes. The module supports ControlLogix chassis hot-swap behavior. Network sessions drop and re-establish after reinsertion.

Q: What is the backplane current limitation impact in multi-module chassis?
A: Each module draws ~1.0 A at 5 VDC. Total chassis power budget must remain within 1756 power supply limits.

Q: Does firmware mismatch affect EtherNet/IP communication stability?
A: Yes. Mismatched firmware between controller and communication module can prevent CIP session establishment.

Field Installation Guidelines

Install the module only in a powered-off ControlLogix chassis when possible. Align the module with the backplane guide rails and fully seat the connector to ensure stable electrical contact. Maintain shielded twisted-pair cabling for RJ-45 Ethernet ports. Ensure proper grounding of the chassis backplane to reduce differential noise on Ethernet PHY lines. Avoid routing EtherNet/IP cables parallel to high-voltage conductors to reduce induced coupling. Verify node IP configuration before enabling network scan cycles. Maintain firmware consistency across all 1756 platform modules before commissioning.