Product Overview

The Allen-Bradley 1786-FS10 is a 10-meter fiber optic cable assembly used in Allen-Bradley ControlNet communication systems. It belongs to the short-distance fiber media range and is intended to connect compatible ControlNet fiber repeater modules and network devices.

Unlike conventional coaxial ControlNet media, the 1786-FS10 uses 200-micron hard-clad silica (HCS) fiber. This allows communication signals to travel between network sections without relying on a continuous electrical connection. Fiber media is particularly useful when automation equipment is installed in separate electrical enclosures or in areas exposed to electromagnetic interference from motors, drives, and high-power switching equipment.

The cable is factory-terminated with Versalink V-system connectors, allowing it to connect directly to compatible fiber interfaces. Its 10-meter length makes it suitable for relatively short connections between repeater modules, drive communication interfaces, and nearby control equipment.

In a typical installation, the cable connects a 1786-RPFS short-distance fiber repeater module to another compatible fiber interface. The repeater system can be used to extend a ControlNet network or connect equipment across electrically noisy areas.

The 1786-FS10 is part of a broader family of preassembled ControlNet fiber cables available in different lengths. Selecting the correct cable length and compatible repeater hardware is important when planning the physical network arrangement.

This cable is a passive communication component. It does not amplify signals or perform network switching independently. Its function is to carry optical communication signals between compatible ControlNet fiber interfaces.

Technical Specifications

Product Features

• 200/230 µm HCS Fiber: Uses hard-clad silica fiber for short-distance ControlNet optical communication.
• Factory-Terminated Connectors: Supplied with Versalink V-system terminations for compatible fiber interfaces.
• 10-Meter Cable Assembly: Suitable for short connections between nearby ControlNet fiber devices.
• Electromagnetic Interference Immunity: Optical transmission avoids the electrical interference problems associated with copper communication cables.
• Dedicated Repeater Compatibility: Intended for use with the Allen-Bradley 1786-RPFS short-distance fiber repeater.
• PVC Cable Jacket: Provides external cable protection for industrial installation.
• 650 nm Operating Wavelength: Matches the optical transmission requirements of the short-distance fiber system.
• Controlled Bending Characteristics: Has a specified minimum bend radius of 25 mm.
• Mechanical Flexibility: Supports more than 5,000 cyclic flexing operations under specified test conditions.
• Industrial Temperature Range: Supports operation between -20 and +80°C.
• Preassembled Cable Design: Eliminates the need for field termination when the supplied connector configuration matches the installation.

Product Working Principle

The 1786-FS10 carries ControlNet communication signals in optical form through its HCS fiber core.

When connected between compatible fiber interfaces, the transmitting device converts electrical communication signals into optical signals at a wavelength of 650 nm. These signals travel through the fiber core and are received by the optical interface at the opposite end, where they are converted back into electrical signals for the connected ControlNet equipment.

A typical communication path is:

ControlNet Coaxial Network → 1786-RPA Repeater Adapter → 1786-RPFS Fiber Repeater → 1786-FS10 → Remote Fiber Interface

The 1786-FS10 itself does not perform electrical-to-optical conversion. That function is handled by the connected repeater or communication hardware.

Its HCS fiber construction is particularly useful in installations where electrical noise could affect conventional copper communication wiring. Since the signal travels as light rather than electrical current, the fiber link is not affected by electromagnetic interference in the same way as coaxial or twisted-pair cables.

The optical power budget of 4.2 dB represents the allowable total loss across the fiber connection, including fiber attenuation, connectors, bulkhead connections, and any splices. Maintaining this loss within the permitted range is necessary for proper communication.

The cable must also be installed without exceeding its minimum bend radius or pull-tension limits. Excessive bending, pulling, or damage to the connector ends can increase optical loss and interrupt communication.

Role in Allen-Bradley ControlNet Network Architecture

The 1786-FS10 operates as the optical transmission medium within a ControlNet fiber repeater arrangement. It allows compatible repeater modules and fiber-enabled devices to exchange network signals across short distances.

In a mixed-media ControlNet installation, coaxial cable may be used for the main trunk network, while fiber optic connections are introduced where electrical isolation, interference immunity, or physical separation is required.

A typical arrangement is:

ControlNet Coaxial Trunk → 1786-RPA Repeater Adapter → 1786-RPFS Short-Distance Fiber Repeater → 1786-FS10 → Remote Fiber Repeater or Compatible Device

The 1786-FS10 is particularly useful when a ControlNet installation needs a short optical connection between repeater modules or compatible fiber communication interfaces.

Industrial Applications

The 1786-FS10 is used in industrial automation environments where short-distance fiber communication is preferred over conventional coaxial connections.

Installation and Maintenance

1. Verify Cable Compatibility: Confirm that the 1786-FS10 is being used with compatible 200/230 µm HCS fiber interfaces and the appropriate repeater hardware.
2. Check Connector Type: Verify that both connection points support the Versalink V-system connectors supplied with the cable.
3. Inspect the Fiber Cable: Check the outer jacket and connector assemblies for cracks, cuts, deformation, or other visible damage.
4. Clean Connector Ends: Ensure that the fiber connector surfaces are clean before installation. Contamination can increase optical loss and affect communication.
5. Protect Unused Connectors: Keep protective caps installed whenever the cable is disconnected from network equipment.
6. Route the Cable Carefully: Select a route that avoids sharp edges, crushing forces, and excessive mechanical tension.
7. Observe the Bend Radius: Maintain a minimum bend radius of 25 mm throughout the installation.
8. Avoid Excessive Pulling: Do not exceed the specified maximum pull tension of 490 N during cable routing.
9. Connect the Fiber Interfaces: Align the Versalink connectors with the corresponding ports on the 1786-RPFS or other compatible equipment.
10. Check Optical Connections: Verify that the connectors are fully seated and that the cable is not kinked or twisted.
11. Verify Network Communication: Restore the system and check the communication status of the connected ControlNet devices.
12. Inspect and Document: Record the cable routing and connection points, and replace the cable if its fiber core or connector assembly has been damaged.

During troubleshooting, inspect connector cleanliness, cable bends, and the condition of the fiber ends before replacing repeater modules. A damaged or contaminated optical connection can cause communication interruptions even when the network electronics are operating normally.

Compatible System Components

Recommended Related Models

Key Advantages

• 200/230 µm HCS fiber construction for ControlNet optical communication.
• Factory-terminated Versalink V-system connectors.
• 10-meter preassembled cable for short-distance connections.
• Immunity to electromagnetic interference.
• Compatible with the 1786-RPFS short-distance fiber repeater.
• Specified minimum bend radius and pull-tension limits for installation planning.
• Supports mixed coaxial and fiber ControlNet network architectures.

Technical FAQs

1. Which ControlNet repeater is compatible with the 1786-FS10?

The 1786-FS10 is intended for use with the Allen-Bradley 1786-RPFS short-distance fiber repeater. The 1786-RPFS uses 200/230 µm HCS fiber and is part of the modular ControlNet repeater system.

2. What is the difference between the 1786-FS10 and the 1786-FS20?

The main difference is cable length. The 1786-FS10 is a 10-meter cable assembly, while the 1786-FS20 provides a 20-meter connection. Both belong to the same short-distance ControlNet fiber cable family and use compatible fiber technology.

3. Why is the 1786-FS10 suitable for environments with electromagnetic interference?

The cable transmits communication signals through optical fiber rather than electrical conductors. This prevents electromagnetic interference from directly coupling into the communication signal, making fiber connections useful around variable-frequency drives, motors, and high-power switching equipment.

4. What precautions are necessary when installing the 1786-FS10?

Maintain a minimum bend radius of 25 mm and avoid exceeding the maximum pull tension of 490 N. Keep the connector ends clean, install protective caps when disconnected, and replace the cable if it becomes kinked or physically damaged.