Product Overview

The Allen-Bradley 1756-ENBT is a high-performance EtherNet/IP communication bridge designed for the ControlLogix 1756 platform. This module serves as a critical gateway, allowing Logix5000 controllers to exchange real-time data with other controllers, I/O devices, and Human-Machine Interfaces (HMI) over a standard Ethernet network. By supporting the Common Industrial Protocol (CIP), the 1756-ENBT facilitates seamless vertical and horizontal integration across the plant floor and enterprise-level systems.

Installed directly into any slot of a ControlLogix chassis, the module provides a 10/100 Mbps copper interface. It is engineered to handle demanding industrial traffic, including high-speed messaging and distributed I/O control, while maintaining the deterministic performance required for complex automation sequences.

Technical Specifications

• Manufacturer: Rockwell Automation / Allen-Bradley

• Model Number: 1756-ENBT

• Module Type: EtherNet/IP Communication Bridge

• Data Rate: 10/100 Mbps (Auto-negotiating)

• Connection Capacity: Up to 128 Logix connections; 64 TCP/IP connections

• Packet Rate: 5,000 packets per second (I/O)

• Backplane Current Draw: 700 mA @ 5.1V DC; 3 mA @ 24V DC

• Protocol Support: EtherNet/IP, CIP, SNMP, HTTP (Embedded Web Server)

• Dimensions: 5.7 x 10.5 x 13 cm

• Weight: 0.2 kg

• Origin: USA

Key Technical Characteristics

• High-Volume Connectivity: Capable of managing up to 128 simultaneous Logix connections, the 1756-ENBT allows a single chassis to communicate with an extensive array of distributed I/O racks, drives, and supervisory software.

• CIP Safety Bridging: The module supports the routing of safety data, enabling it to act as a bridge for GuardLogix systems. This allows for SIL3/PLe safety communication across different segments of the Ethernet network without compromising safety integrity.

• Embedded Web Server: Features an internal web server that provides real-time module diagnostics and network statistics via a standard web browser, simplifying field troubleshooting and remote monitoring.

• Deterministic Messaging: Optimized for RPI (Requested Packet Interval) performance, the module ensures that critical I/O data is delivered reliably, supporting high-speed producer/consumer tag synchronization between controllers.

• Robust Network Integration: Supports various network topologies including star and tree. It functions as a bridge for messages between ControlLogix backplanes and the Ethernet network, effectively extending the reach of the automation system.

• Security and Management: Provides SNMP (Simple Network Management Protocol) support for integration into standard IT network management tools and supports electronic keying to prevent accidental module mismatch during replacement.

Industrial Applications

The 1756-ENBT is a standard component for modernizing industrial networks, commonly used in:

• Distributed I/O control across large-scale manufacturing lines.

• Controller-to-Controller data synchronization in coordinated drive systems.

• Interfacing ControlLogix racks with SCADA and MES software suites.

• Ethernet-based safety communication in GuardLogix architectures.