Allen-Bradley 1771-AF PLC Redundancy Module

Description

Allen-Bradley 1771-AF PLC Redundancy Module

Product Dimensions：

The Allen-Bradley 1771-AF is a Fiber Optic Converter module belonging to the legacy PLC-5 Universal I/O chassis system. It serves as a critical interface for extending the reach of Remote I/O (RIO) or Data Highway Plus (DH+) networks using fiber optic cabling instead of traditional twinaxial copper.

Product Detailed Description

The 1771-AF acts as a “transparent” bridge between electrical signals and optical signals. In industrial environments where electromagnetic interference (EMI) or long distances are factors, the 1771-AF converts the standard 1771 RIO/DH+ signals into light pulses. It is designed to be installed in a standard 1771 I/O chassis and requires no complex software configuration; it primarily functions as a physical layer converter.

Technical Parameters

Product Advantages

• Noise Immunity: Since fiber optics use light rather than electricity, the 1771-AF is completely immune to electrical noise, RFI, and EMI, making it ideal for welding areas or high-voltage environments.
• Extended Range: It significantly exceeds the distance limitations of standard copper twinax cable (which degrades over long runs), allowing for distributed I/O across large plants.
• Ground Loop Elimination: Fiber optic cable provides electrical isolation between different parts of a factory, preventing ground potential differences from damaging equipment.
• Plug-and-Play: The module is essentially transparent to the PLC-5 processor; if the copper network was working, the fiber link will work without code changes.

Important Considerations (Precautions)

• Point-to-Point Topology: The 1771-AF is designed for point-to-point or star configurations. You typically need a pair of modules (one at each end) to complete the link.
• Bend Radius: Fiber optic cables are fragile. Ensure the installation respects the minimum bend radius to avoid “micro-fractures” in the glass that cause signal loss (attenuation).
• Dust Protection: Always keep the protective dust caps on the ST connectors when not in use. Even microscopic dust particles can block the 820nm light signal.
• Legacy Status: As part of the 1771 series, this product is in the “End of Life” (EOL) or “Discontinued” phase. Finding new units may be difficult; most available units are refurbished or surplus.

Product Applications

• Large Scale Manufacturing: Connecting remote I/O racks in different buildings or across large assembly lines (e.g., automotive plants).
• High-Interference Zones: Near large motors, power generators, or induction furnaces where copper communication would be unreliable.
• Outdoor Links: Running communication lines between outdoor tanks or silos where lightning strikes might otherwise travel through copper wiring.

Shipping Port: Xiamen, China

Payment: Bank of Chicago, Bank of Singapore

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