Allen-Bradley 1786-RPFM ControlNet Modular Repeater Medium Distance Fiber Module

The Allen-Bradley 1786-RPFM/A, also cataloged as the 1786-RPFM Ring Repeater, operates as a dedicated hardware component for network physical-layer conversion within ControlNet System networks.

Hardware Specifications

Profinet / EtherNet/IP Deterministic Networks and I/O Density Scaling

The Allen-Bradley 1786-RPFM/A executes signal re-transmission routines over 1300 nm optical infrastructure to extend control segments alongside synchronous platforms linked through Profinet / EtherNet/IP deterministic networks. The dual fiber optic channels transition electrical backplane data packets into optical pulses at a fixed communication rate of 5 Mbps. This expansion layer interacts directly with the hosting 1786-RPA repeater bus. The 400 mA current limit on the 5 VDC internal line directly governs the local I/O density scaling inside the modular assembly, preserving specific propagation times across long-distance topologies up to 3000 m.

Frequently Asked Questions

Q: Does the 1786-RPFM/A hardware interface permit hot-swap procedures while active communication is passing through the repeater chassis?

A: No. This module does not support hot-swap capabilities. De-energize the primary 1786-RPA adapter assembly before seating or unseating the module from the slot. Disconnection under power interrupts the optical ring link, resulting in immediate network failure and potential backplane driver damage.

Q: What are the degradation thresholds allowed for the fiber optic connections on this specific hardware?

A: The optical budget enforces a strict attenuation limit of less than 13.3 dB per complete fiber link. Any combination of fiber run lengths, physical splices, and ST-type connector insertions exceeding this value will cause packet dropouts and affect network execution.

Field Installation Guidelines

• Chassis and Rail Coupling: Securely seat the module onto the 1786-RPA repeater adapter base before clipping the combined assembly onto the DIN rail. Ensure the multi-pin side connector pins align flush with the receiver logic sockets.
• Fiber Bend Radius Constraints: Maintain the standard minimum bend radius for 62.5/125 um multimode fiber cables during installation within the panel ducts. Avoid sharp crimping to prevent optical core fractures and localized high attenuation zones.
• Enclosure Specifications: Mount the module within a sealed industrial control enclosure accessible only via a tool. This configuration maintains the target Pollution Degree 2 environment and protects active optoelectronic connections from airborne contaminants.
• ST Connector Alignment: Clean the ST-type cable ends before insertion. Align the physical bayonet keyways correctly, push inward, and rotate the outer collar clockwise until locked to ensure the 1300 nm beam centers exactly onto the transceiver face.