Allen-Bradley 1756-EN3TR EtherNet-IP Network Interface Module

Dual-port EtherNet/IP interface module for ControlLogix, the Allen-Bradley 1756-EN3TR (firmware revision B) delivers 10/100 Mbps Ethernet connectivity from a 1756 backplane to Ethernet/IP devices. It uses two copper RJ-45 ports for network access and supports up to 128 TCP connections, enabling numerous concurrent I/O and messaging operations. Designed to mount in a ControlLogix chassis, the EN3TR bridges the backplane to the Ethernet/IP network, supporting standard EtherNet/IP data exchange for I/O and explicit messaging. The module carries a continuous isolation rating of 30 V and uses basic insulation between the Ethernet network and the backplane, with type testing up to 980 V AC for 60 seconds for safety. Typical power characteristics include about 5.1 W of dissipation, a 1 A draw at 5.1 V, and about 3 mA at 24 V, reflecting the module’s modest on-board power needs in industrial environments. Operating temperature is 0 to 60 °C, making it suitable for many factory floor applications, including high-speed PLC-to-device communication for remote I/O, HMIs, servo drives, and distributed control systems via EtherNet/IP.