Introduction to the Allen-Bradley 1756-EN2TR
When your ControlLogix chassis needs reliable, high-speed Ethernet communication, the Allen-Bradley 1756-EN2TR delivers. This EtherNet/IP bridge module provides dual 10/100 Mbps ports, enabling redundant network topologies that keep your operation running even if one path fails. As part of the ControlLogix series, it integrates seamlessly into existing systems and supports real-time control, time synchronization, and motion applications.
Technical Specifications That Matter
The 1756-EN2TR is built for demanding industrial environments. Its dual RJ45 ports support 10/100 Mbps transmission with auto-negotiation, while a USB 1.1 port allows for local configuration. The module draws 1 amp at 5 volts from the backplane and 3 milliamps at 24 volts, with a total power consumption of 5.1 watts. It handles up to 128 TCP/IP connections and 256 Logix connections, making it suitable for large-scale networks. With support for up to 8 axes of integrated motion, it can coordinate complex motion control tasks. The module operates in temperatures from 32 to 140 degrees Fahrenheit (0 to 60 degrees Celsius) and has a thermal dissipation of 21.28 BTU per hour.
Key Features and Benefits
- Redundant Network Support: Dual ports enable Ring and Linear topologies, plus Parallel Redundancy Protocol (PRP) for high availability.
- High Connection Capacity: Supports 128 TCP/IP and 256 CIP connections simultaneously.
- Integrated Motion: Controls up to 8 axes over EtherNet/IP without additional hardware.
- CIP Safety: Allows simultaneous transfer of safety and control data.
- Flexible Installation: Fits any slot in a ControlLogix chassis with a slot width of 1.
Applications and Use Cases
Redundant Ethernet Networks
In critical processes, network downtime is unacceptable. The 1756-EN2TR’s dual ports and Device Level Ring (DLR) support ensure that if one cable or switch fails, communication continues uninterrupted. This is ideal for automotive assembly lines or continuous manufacturing.
Motion Control Integration
With support for up to 8 axes, this module can handle complex motion profiles in packaging, printing, or robotics. It eliminates the need for separate motion controllers, reducing cost and complexity.
Plant-Wide Information Exchange
The module facilitates messaging between ControlLogix controllers and other Allen-Bradley PLCs like SLC 500, PLC-5, and MicroLogix. It also integrates with HMIs, SCADA systems, and third-party gateways, enabling seamless data flow across the plant floor.
Installation and Configuration
Installing the 1756-EN2TR is straightforward. It fits into any slot of a ControlLogix chassis. For wiring, use unshielded RJ45 Category 5 or 6 twisted-pair cables. Initial IP address configuration can be done using the Allen-Bradley BOOTP-DHCP tool. The module supports explicit protected mode and electronic keying for secure operation. No scheduling or routing tables are required, simplifying setup.
Maintenance and Reliability
To ensure long-term reliability, periodically inspect connections and verify that the module is free from dust and debris. The operating temperature range of 32 to 140 degrees Fahrenheit (0 to 60 degrees Celsius) means it can handle typical industrial environments. The 1756-EN2TR’s solid-state design has no moving parts, minimizing wear. For safety-related applications, always follow the manufacturer’s safety manual and perform regular diagnostics.
Compatibility and Integration
The 1756-EN2TR communicates over EtherNet/IP and is compatible with a wide range of Allen-Bradley products, including Flex I/O, POINT I/O redundant Ethernet adapters, CompactLogix, and ControlLogix controllers. It also supports third-party devices through encompass partner modules and gateways. The module’s ability to share a common application layer with ControlNet and DeviceNet simplifies migration and integration.
Selection Guide
Before purchasing, verify that your application requires EtherNet/IP communication and that you have available slots in your ControlLogix chassis. Consider the number of connections needed: 128 TCP/IP and 256 CIP connections are supported. If you need redundant networking, the dual ports are essential. For motion control, confirm that your system can utilize up to 8 axes. SpareTechPLC offers the 1756-EN2TR and can help you determine if it’s the right fit for your setup.
Frequently Asked Questions
What is the difference between the 1756-EN2TR and other ControlLogix Ethernet modules?
The 1756-EN2TR features dual ports for redundant network topologies, while many other modules have a single port. It also supports up to 8 axes of motion and 128 TCP/IP connections.
Can I use the 1756-EN2TR in a non-redundant network?
Yes, the module can be used in standard linear or star topologies. The dual ports provide flexibility for future redundancy upgrades.
What cable type is required for the 1756-EN2TR?
Use unshielded RJ45 Category 5 or 6 twisted-pair cables for Ethernet connections.
How do I configure the IP address?
You can use the Allen-Bradley BOOTP-DHCP tool to assign an IP address to the module.
Does the 1756-EN2TR support safety applications?
Yes, it meets the CIP safety standard and can transfer safety and control data simultaneously.
