Product Overview
The Allen-Bradley 1756-EN2TR is a ControlLogix EtherNet/IP bridge module designed for reliable communication in industrial automation. As part of the ControlLogix series from Rockwell Automation, this module provides dual-port 10/100 Mbps connectivity for redundant Ethernet networks. It supports up to 128 TCP/IP connections and 256 CIP connections, making it suitable for real-time control, motion, and safety applications.
Technical Specifications Breakdown
Key parameters for the 1756-EN2TR are listed below for quick reference:
| Feature | Specification |
|---|---|
| Module Type | Ethernet Communication Module |
| Series | ControlLogix |
| Ethernet/IP Communication Rate | 10/100 Mbps |
| Integrated Ports | Two (2) RJ45; One (1) USB 1.1 |
| Backplane Current (5 Volts) | 1 amp |
| Backplane Current (24 Volts) | 3 milliamps |
| Power Consumption | 5.1 Watts |
| Power Dissipation | 5.1 W |
| Thermal Dissipation | 21.28 BTU per hour |
| Current Draw | 1.2 Amp |
| Insulation Voltage | 30 Volts Continuous |
| Operating Temperature | 32 to 140 degrees Fahrenheit (0 to 60 degrees Celsius) |
| Slot Width | 1 |
| Enclosure | Open |
Industry Applications
From a maintenance engineer's perspective, the 1756-EN2TR excels in environments requiring high network availability. Its dual RJ45 ports enable redundant ring or star topologies, minimizing downtime during cable faults. Typical applications include:
- Real-Time Control: The module handles I/O messaging and tag exchange for distributed control systems.
- Motion Control: With support for up to 8 axes on EtherNet/IP, it integrates servo drives and actuators.
- Safety and Diagnostics: It meets CIP safety standards, allowing simultaneous transfer of safety and diagnostic data.
Installation & Setup Guidance
Install the module in any slot of a ControlLogix chassis. Use unshielded Category 5 or 6 twisted-pair cables with RJ45 connectors. Configure the IP address using the Allen-Bradley BOOTP-DHCP tool. Ensure proper grounding and follow standard ESD precautions during handling.
Maintenance & Reliability
Inspect the module periodically for dust accumulation and ensure ambient temperature stays within 0 to 60 °C. The open enclosure design requires clean, dry environments. Verify backplane current draw (1 A at 5 V, 3 mA at 24 V) to avoid overloading the chassis power supply.
Compatibility & Integration
The 1756-EN2TR communicates with ControlLogix, CompactLogix, Flex I/O, POINT I/O, and legacy controllers like SLC 500 and PLC-5. It also interfaces with HMIs and SCADA systems. The USB 1.1 port aids local configuration.
Selection Guide & Purchasing Advice
Contact SpareTechPLC to verify current lifecycle status and availability before ordering. This module is ideal for upgrading existing ControlLogix networks to support redundant EtherNet/IP.
Troubleshooting & Common Issues
- No Communication: Check IP address configuration via BOOTP-DHCP. Verify cable integrity (Cat 5e or better).
- Slow Performance: Ensure network switches support 10/100 Mbps auto-negotiation. Reduce TCP/IP connection count if nearing 128.
- LED Indicators: Refer to the user manual for status LED patterns.
