Description
The 1756-EN2TXT A is an EtherNet/IP bridge module for the Rockwell Automation / Allen-Bradley ControlLogix 1756 platform. It connects a ControlLogix chassis to an EtherNet/IP network and lets the controller exchange data with HMIs, VFDs, remote I/O, other controllers and engineering workstations while the chassis I/O remains local to the processor.
In short, the 1756-EN2TXT A is the module that makes a ControlLogix rack visible on the plant network. It is an enhanced version of the 1756-EN2T family, adding Quick Connect, time synchronization and media-redundancy features to the standard EtherNet/IP bridge role.
Application Scenarios
A steel coil-coating line had a ControlLogix rack in the main panel, a remote I/O rack at the entry end 180 metres away, a PowerFlex 755 drive on the bridle, an HMI at the operator desk and a second controller on the exit end that needed the line speed as a produced tag. The original network design used one EtherNet/IP bridge and a lot of hope: the drive commissioning and the HMI trending fought over connection capacity, and a contractor’s laptop plugged into the switch would occasionally trigger a network storm that the module could not handle.
Replacing the bridge with the 1756-EN2TXT A changed the shape of the problem rather than its size. Quick Connect let the drives establish their I/O connections in the time it takes the guard door to close, so the line reached full speed inside the first scan instead of wandering up over several seconds. Time synchronization gave every event on the line the same timestamp, which finally let the engineers correlate a bridle-slip alarm with a drive-fault code that had been logged three milliseconds earlier on a different device. And when a contractor’s laptop flooded the switch with broadcast traffic, the module’s resilience — tested at 5000 ARP frames per second for five minutes — kept the I/O connections alive while the IT department dealt with the source.
Parameter
| Main Parameters | Value / Description |
|---|---|
| Product Model | 1756-EN2TXT A (enhanced EtherNet/IP bridge, Series A) |
| Manufacturer | Allen-Bradley / Rockwell Automation |
| Product Category | EtherNet/IP communication bridge module for ControlLogix |
| Network Protocol | EtherNet/IP (CIP, CIP Motion, CIP Safety, CIP Sync, Time Synchronization, Quick Connect) |
| Ports | 2 × RJ45, 10/100Base-TX, full-duplex, auto-negotiating, auto-crossover |
| Transmission Distance | 100 m per port (Cat5e or better, shielded twisted-pair recommended) |
| Network Nodes | 256 standard + 128 redundant |
| I/O Connections | 128 standard + 128 redundant; 64 multicast capable |
| Message Size | 504 bytes |
| Backplane Current Draw | 1.2 A @ 5.1 V DC |
| Power Dissipation | 6.4 W (21.8 BTU/hr) |
| Dimensions (H × W × D) | 139 × 30 × 140 mm (5.47 × 1.18 × 5.51 in) |
| Weight | Approx. 0.4 kg |
| Status Indicators | Module status, network status, link/activity per port, network activity |
| Mounting | 1 slot in a 1756 chassis |
| Configuration | Studio 5000 Logix Designer / RSLogix 5000, via the I/O Configuration tree |
| Electronic Keying | Yes, software-configurable |
| Cable Type | Shielded Category 5e or better; unshielded cable is permitted but not recommended |
| Installation Clearance | 50 mm above and below the module |
| Operating Temperature | 0 … 60 °C (32 … 140 °F) |
| Storage Temperature | -40 … 85 °C (-40 … 185 °F) |
| Relative Humidity | 5 … 95 % non-condensing |
| Shock / Vibration | 30 g operating, 50 g non-operating; 2 g at 10 … 500 Hz |
| Certifications | UL 508, cUL, CE, C-Tick, ATEX, FM, KC, IECEx, ABS marine |
| Compatible Chassis | 1756-A4, A7, A10, A13, A17, A4K, A7K, A7R, BERRY |
| Compatible Products | 1756-EN2T, EN2TR, EN3T, EN4TR (family); 1756-RM2 (redundancy); 1756-L8x controllers; 1756 I/O; 5069 I/O; 1794 I/O; 1734 I/O |
| Compatible HMI / Drive | PanelView 5000; PowerFlex 525, 755, 755T; Kinetix 5500, 5700 |
| Country of Origin | United States |
| Lifecycle | Active; confirm lead time and firmware compatibility with the current Rockwell price list |
