Get now 1794-AENTR to build a resilient, redundant industrial network with Device Level Ring (DLR) technology. The Allen-Bradley 1794-AENTR is a high-availability EtherNet/IP adapter module featuring two RJ45 ports. This dual-port design allows the module to be integrated into a ring topology, ensuring that a single cable failure does not bring down the entire I/O rack. By providing a fault-tolerant path for time-critical data, the 1794-AENTR is the industry standard for mission-critical applications in oil and gas, power generation, and high-speed logistics. It maintains full compatibility with the 1794 Flex I/O platform, supporting up to eight modules while offering the same high-speed 10/100 Mbps performance as its single-port predecessor, but with the added layer of network physical redundancy.
What Is the 1794-AENTR?
The 1794-AENTR is the dual-port, DLR-capable version of the Flex I/O Ethernet adapter. It serves as the bridge between an EtherNet/IP ring and the local I/O modules. In a DLR configuration, the 1794-AENTR acts as a node that can pass data in two directions. If the ring is broken, the DLR supervisor re-routes the traffic, and the 1794-AENTR continues to process I/O data without interruption (bumpless transfer). This module is also capable of being used in a «linear» topology, daisy-chaining multiple racks together without the need for an external switch, which significantly reduces the cost of network hardware and cabling in long-distance conveyor or pipeline applications.
Key Technical Specifications
- Part Number: 1794-AENTR
- Manufacturer: Allen-Bradley / Rockwell Automation
- Network Protocol: EtherNet/IP with DLR support
- Ports: 2 x RJ45 (10/100 Mbps)
- Topology Support: Ring, Linear, Star
- Module Support: Up to 8 modules per adapter
- Input Power: 24V DC (19.2 to 31.2V DC range)
- Flexbus Current: 640 mA maximum
- CIP Sync: Supports precision time protocol for synchronized motion
Fault Tolerance and Industrial Reliability
The 1794-AENTR is designed for maximum uptime. Its ability to support DLR means that maintenance teams can replace damaged Ethernet cables during active production hours without stopping the process. Beyond redundancy, the module supports CIP Sync, allowing it to be used in high-precision applications where multi-axis coordination is required over an Ethernet backbone. Its rugged design ensures it can withstand the electrical noise and vibration of a factory floor while providing the most advanced diagnostics available in the Flex I/O family.
Maintenance Tips
When maintaining a 1794-AENTR in a DLR ring, periodically check the «Ring State» diagnostic in Studio 5000. An expert tip: if the ring is in «Partial» state, one cable is already failed; don’t wait for the second failure to take action. Also, ensure the firmware versions are synchronized across all 1794-AENTR modules in the ring to prevent timing mismatches. If the module’s «Network» LED flashes red, it typically indicates an IP address conflict on the ring. During cleaning, ensure no moisture enters the unused second port if you are using it in a star or linear end-of-line configuration; always use a protective RJ45 dust cap to prevent oxidation of the pins.
Frequently Asked Questions
Q: Can I use the two ports on the 1794-AENTR to connect to two different networks?
A: No. The two ports act as an internal switch for the same network. They are designed for daisy-chaining or ring redundancy within a single subnet.
Q: What is the maximum number of nodes in a DLR ring with 1794-AENTR?
A: Rockwell Automation recommends a maximum of 50 nodes per DLR ring to maintain optimal recovery times (under 3ms), though the hardware can technically support more.
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