Overview
The Allen-Bradley 1756-ENBT is a communications module for the ControlLogix system that enables Ethernet/IP data transfer between controllers, I/O devices, and distributed automation networks. As an Ethernet/IP bridge, this module supports 64 TCP connections and 128 CIP connections, allowing flexible real-time messaging and information exchange at 10/100 Mbps. It functions as a copper communication interface without an enclosure, fitting any slot in a 1756 chassis for seamless integration into existing control architectures.
Key Features
- Supports 64 TCP/IP connections and 128 Logix (CIP) connections for distributed I/O control
- 10/100 Mbps Ethernet/IP communication with auto-negotiating full or half duplex modes
- Single RJ45 Category 5 Ethernet port for direct network connection
- Web-enabled diagnostics: IP traffic, TCP/UDP monitoring, collision histogram, and connection management
- Supports real-time I/O messaging, information exchange, and general messaging protocols
- Open enclosure design—installs in any slot within ControlLogix chassis
Technical Specifications
- Communication Rate: 10/100 Mbps Ethernet/IP
- Backplane Current: 700 mA @ 5.1 VDC; 3 mA @ 24 VDC
- Power Dissipation: 3.7 W
- Thermal Dissipation: 12.6 BTU/hour
- Isolation Voltage: 30 VDC continuous (basic insulation)
- Ethernet Port: 1× RJ45 Category 5 (shielded or unshielded cable)
- TCP Connections: 64
- CIP Connections: 128
- Operating Temperature: 0–60°C (32–140°F)
- Humidity: 5–95% non-condensing
- Slot Width: 1
- Weight: 0.44 lbs
- Supply Voltage: 24 VDC
Typical Applications
- Connecting multiple ControlLogix processors over a single Ethernet/IP backbone network
- Distributed I/O control: remote device communication and messaging
- Real-time motion and drive coordination across network nodes
- Data acquisition and system diagnostics via web-enabled interface
- Integration of legacy NetLinx networks into modern Ethernet/IP infrastructure
- Multi-plant or multi-zone automation with centralized control architecture
Compatibility & Replacements
Compatible With
- ControlLogix 1756-series chassis (any slot)
- CompactLogix and ControlLogix processors (firmware 6.006 or later)
- RSLogix 5000 software (version 8.02.00 and later)
- Studio 5000 Logix Designer (all current versions)
- EtherNet/IP protocol devices and gateways
- Real-time I/O and information messaging systems
Replaces / Drop-In Replacement For
- Existing 1756-ENBT modules requiring refresh or repair
- Note: 1756-ENBT was discontinued by manufacturer on December 31, 2021
- Modern functional replacement: Allen-Bradley 1756-EN2T (Ethernet/IP dual-port module)
Works With
- EtherNet/IP protocol (IEC 61131-5 compliant)
- Common Industrial Protocol (CIP) for safety-critical data transmission
- Rockwell Automation Add-On Profiles (AOP) for 1756-ENxT modules
- EDS (Electronic Data Sheet) files available for network configuration
- Web server diagnostics and connection management tools
