1786-RPFS Allen-Bradley | ST Connector ControlNet Fiber Plug

Allen-Bradley 1786-RPFS Series A ControlNet Fiber Optic Module

Product Overview

The 1786-RPFS (Series A) is a high-reliability short-distance fiber optic repeater module from the Allen-Bradley ControlNet communication family. Manufactured by Rockwell Automation, this module is specifically engineered to bridge ControlNet segments using multimode fiber optic media. By converting electrical signals into light pulses, the 1786-RPFS provides total galvanic isolation and immunity to electromagnetic interference (EMI), which is critical for maintaining deterministic communication in plants with heavy motor activity, welding interference, or variable frequency drives. The module actively regenerates and retimes the ControlNet signal, allowing for reliable data transmission over moderate distances while supporting flexible network topologies.

Technical Specifications

The 1786-RPFS is built for high-speed signal processing within modular repeater racks.

• Manufacturer: Rockwell Automation / Allen-Bradley

• Model Number: 1786-RPFS

• Hardware Revision: Series A

• Module Type: Fiber Optic Repeater (Short-to-Medium Distance)

• Media Type: Multimode Fiber Optic (62.5/125 µm recommended)

• Maximum Distance: Up to 3 km (approx. 1.86 miles) depending on fiber quality and connections

• Connector Type: Dual ST (Straight Tip) connectors

• Optical Wavelength: 820 nm

• Backplane Current Draw: 400 mA @ 5 VDC

• Network Topologies: Star, Ring, and Point-to-Point (via repeater adapters)

• Communication Rate: 5 Mbps (Standard ControlNet)

• Operating Temperature: 0°C to +60°C (32°F to 140°F)

• Storage Temperature: -40°C to +85°C (-40°F to +185°F)

• Status Indicators: LED diagnostics for optical link and power status

• Certifications: CE, UL, CSA compliance for industrial environments

Core Performance Features

• EMI/RFI Immunity: The use of fiber optic media ensures that the ControlNet signal is shielded from electrical noise, preventing data packet corruption and reducing network "retry" rates in harsh environments.

• Signal Regeneration: Unlike passive splitters, the 1786-RPFS retimes the digital pulses to eliminate jitter, ensuring that the strict Concurrent Time Slot (NUT) requirements of ControlNet are met over extended distances.

• Topological Flexibility: When paired with a 1786-RPA adapter, the 1786-RPFS allows for a seamless transition from copper coax to fiber optic segments, enabling the creation of robust star or self-healing ring architectures.

• Energy Efficient Design: Low power consumption (400 mA @ 5V) allows for high-density installation within modular repeater racks without specialized cooling.