Allen-Bradley 1756-ENBT ControlLogix EtherNet/IP Bridge Module | 10/100 Mbps RJ45

The 1756-ENBT is an EtherNet/IP bridge communication module manufactured by Allen-Bradley, the flagship industrial automation brand of Rockwell Automation, and ranks among the most widely deployed network interfaces in the 1756 ControlLogix platform. Occupying a single slot in any 1756 ControlLogix chassis, the 1756-ENBT bridges the high-speed ControlLogix backplane to standard IEEE 802.3 Ethernet networks, allowing Logix processors to exchange I/O data, controller-to-controller messages, and programming traffic across plant-wide Ethernet infrastructures.santaclarasystems.com+1

Functioning simultaneously as a network bridge, remote I/O adapter, and messaging gateway, the 1756-ENBT supports up to 64 TCP/IP connections and 128 CIP (Common Industrial Protocol) connections — a capacity usable in any combination of explicit messaging (HMI queries, programming sessions, peer-to-peer MSG instructions) and implicit I/O connections (rack-optimized or direct data exchange). The module sustains throughput of up to 5000 I/O packets per second and handles up to 64 unconnected messages in each direction across both the backplane and the Ethernet port, providing the bidirectional data flow that modern manufacturing execution, SCADA, and historian systems demand.automation-networks.com+1

The 1756-ENBT served as the workhorse EtherNet/IP interface for ControlLogix systems built from the late 1990s through the 2010s, hosting programming workstations running RSLogix 5000, operator interfaces, MES gateways, and distributed I/O chassis across local, remote, and multi-node network topologies. Its 10/100 Mbps auto-negotiating RJ45 copper port, front-panel status LED display, and removable firmware-upgradeable design made it a standard selection in thousands of installations spanning automotive, food and beverage, water treatment, oil and gas, packaging, and general manufacturing.

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Description

 

Technical Specifications

Parameter Name Parameter Value
Product Model 1756-ENBT
Manufacturer Allen-Bradley (Rockwell Automation)
Product Type EtherNet/IP Bridge Communication Module
Series / Platform 1756 ControlLogix
Ethernet Ports 1 × RJ45 Category 5 (10/100 Mbps auto-negotiating)
Network Standard IEEE 802.3 compliant, shielded or unshielded twisted pair
TCP Connections 64 maximum
CIP Connections 128 maximum (any combination of explicit and implicit)
CIP Unconnected Messages 64 + 64 (backplane + Ethernet)
I/O Packet Rate Up to 5000 packets per second
Current Draw 700 mA @ 5.1V DC; 3 mA @ 24V DC
Power Dissipation 3.7 W (12.6 BTU/hr)
Isolation Voltage 30V continuous (Ethernet network to backplane); type-tested at 707V DC @ 60 s
Enclosure Type Rating None (open-style) — ControlLogix chassis mounted
Slot Width 1 ControlLogix slot
Display Module status LEDs (digital)
Wiring Category Category 2 on Ethernet ports
Dimensions 140 × 40 × 118 mm (5.51 × 1.57 × 4.65 in)
Weight 0.32 kg (0.71 lbs)
Operating Temperature 0 °C to 60 °C (32 °F to 140 °F)
Storage Temperature –40 °C to 85 °C (–40 °F to 185 °F)
Relative Humidity 5% to 95% non-condensing
Vibration / Shock 2 G @ 10–500 Hz vibration; 30 G operating / 50 G non-operating shock
Emissions CISPR 11 Class A
Certifications UL Listed, c-UL-us, CSA, CE, ATEX, Australian C-Tick
Country of Origin United States of America

 

 

Main Features and Advantages

Dual-Role Bridge Architecture: The 1756-ENBT functions simultaneously as a backplane-to-Ethernet bridge and a remote I/O adapter, allowing a single module to service programming workstations, HMI clients, SCADA historians, and distributed I/O chassis at the same time. This dual-role capability eliminates the need for separate network interface cards in many ControlLogix architectures, reducing chassis slot consumption and overall system complexity.santaclarasystems.com+1

Balanced Connection Capacity for Plant-Scale Systems: With 64 TCP/IP and 128 CIP connections available in any combination, the 1756-ENBT supports substantial multi-client environments — a typical mid-sized plant node can comfortably host a programming laptop, one or two HMIs, a data historian, and several rack-optimized I/O adapters simultaneously. Engineers managing connection budgets across multiple remote chassis can plan system growth with confidence within this envelope.santaclarasystems.com+1

Efficient 5000 Packet-Per-Second Throughput: The 1756-ENBT delivers up to 5000 I/O packets per second across its connection pool, a figure that comfortably supports dozens of rack-optimized I/O adapters and direct-connect drives on a single module. For applications requiring higher throughput, adding a second ENBT module or migrating to the 1756-EN2T family provides a scalable path without changing the chassis architecture.industrialmonitordirect.com+1

Standard EtherNet/IP Protocol Compliance: As a fully compliant CIP device, the 1756-ENBT interoperates seamlessly with any other EtherNet/IP product — drives, distributed I/O, motor control centers, and third-party devices supporting the Common Industrial Protocol. Configuration through RSLogix 5000 or Studio 5000 Logix Designer uses standard Add-On Profiles, eliminating the custom driver work that often burdens multi-vendor integration.santaclarasystems.com+1

Robust Industrial Design: Tested to 30 G operating shock, 2 G vibration across the 10–500 Hz band, and 5–95% non-condensing humidity, the 1756-ENBT is engineered for the electrical noise, mechanical stress, and thermal variation typical of plant-floor control rooms. Its Class A CISPR 11 emissions profile and 6 kV contact / 8 kV air ESD immunity keep the module stable even in installations with extensive switching loads.santaclarasystems.com

Proven Legacy Platform Reliability: Having served as the ControlLogix EtherNet/IP standard for more than two decades, the 1756-ENBT benefits from an exceptionally mature firmware base, exhaustive field validation across every industrial sector, and extensive Rockwell knowledgebase documentation — making troubleshooting straightforward even for engineers encountering the module for the first time.

Contact Us WhatsApp / Wechat:+86 18150087953
Phone:+86 18150087953
Email:sales@cxplcmro.com