ControlNet Fiber Ring Solution — Allen-Bradley 1786-RPFM | ControlNet Series
Where This Product Is Used
The Allen-Bradley 1786-RPFM ControlNet Fiber Ring Medium Repeater is deployed in demanding industrial environments where copper-based ControlNet segments must be extended, isolated, or bridged via fiber optic media. Typical application sites include:
- Automotive Assembly Lines — Connecting distributed PLC racks across paint booths and weld cells where EMI interference is severe and segment distances exceed copper limits.
- Oil & Gas Processing Plants — Linking remote I/O drops and drive panels in hazardous areas where intrinsic safety and long-distance fiber runs are mandatory.
- Water & Wastewater Treatment Facilities — Integrating pump stations and SCADA nodes across large geographic footprints using fiber ring redundancy for continuous uptime.
- Power Generation & Utilities — Extending ControlNet rings between control rooms and switchgear buildings where electrical isolation between segments is critical.
- Pharmaceutical & Food Manufacturing — Supporting validated, deterministic ControlNet networks in cleanroom and washdown environments requiring fiber’s immunity to moisture and chemicals.
- Mining & Metals — Bridging surface and underground control systems over long fiber runs where copper attenuation and ground potential differences are prohibitive.
Technical Specifications
| Attribute | Value |
|---|---|
| Part Number | 1786-RPFM |
| Manufacturer | Allen-Bradley / Rockwell Automation |
| Product Family | ControlNet Media Components |
| Device Type | Fiber Ring Medium Repeater |
| Network Protocol | ControlNet (IEEE 802.4 token bus, deterministic) |
| Fiber Type | Multimode fiber optic (62.5/125 µm) |
| Connector Type | ST (IEC 60874-10) |
| Max Segment Distance | Up to 3 km per fiber segment (application dependent) |
| Data Rate | 5 Mbps |
| Supply Voltage | 24V DC (external power required) |
| Operating Temperature | 0°C to 60°C (32°F to 140°F) |
| Storage Temperature | -40°C to 85°C |
| Relative Humidity | 5% to 95% non-condensing |
| Enclosure Rating | IP20 (panel mount) |
| Dimensions (H × W × D) | Refer to Rockwell publication 1786-IN009 |
| Weight | Approx. 150 g |
| Certifications | UL, CE, cUL |
Why Engineers Specify This Model
- Deterministic Ring Topology — The 1786-RPFM maintains ControlNet’s time-division multiplexing (TDM) scheduling across fiber segments, preserving the deterministic, repeatable performance that motion control and safety applications demand.
- EMI/RFI Immunity — Fiber optic media eliminates ground loops and electromagnetic interference, making this repeater the correct choice for high-voltage switchgear rooms, VFD-dense panels, and arc welding environments.
- Electrical Isolation — Provides galvanic isolation between ControlNet copper segments, protecting PLCs and I/O from transient voltage events and ground potential differences between buildings.
- Extended Reach — Overcomes the 1,000 m copper segment limit of standard ControlNet, enabling fiber runs of up to 3 km to connect remote field panels without signal degradation.
- Ring Redundancy Support — When used in a fiber ring configuration, the 1786-RPFM supports automatic fault recovery, maintaining network communication even if a single fiber segment is severed.
- Seamless Integration — Fully compatible with existing Allen-Bradley ControlNet infrastructure including 1756-CNB, 1747-SCNR, and 1771-ACN15 modules without firmware changes.
Complete System Bill of Materials
A typical ControlNet fiber ring extension using the 1786-RPFM requires the following components:
- 1786-RPFM — ControlNet Fiber Ring Medium Repeater (this unit)
- 1786-RPA or 1786-RPCD — Copper-side ControlNet repeater (if bridging copper-to-fiber)
- 1786-TPS or 1786-TPR — ControlNet coax tap (for copper segment termination)
- Multimode fiber optic cable, 62.5/125 µm, ST-terminated (field-supplied per run length)
- ST fiber patch panels and enclosure (field-supplied)
- 24V DC DIN-rail power supply (e.g., 1606-XLP or equivalent)
- 1756-CNB / 1756-CNBR — ControlLogix ControlNet Bridge Module (scanner side)
- 1747-SCNR — SLC 500 ControlNet Scanner (if SLC-based system)
- ControlNet network configuration software: RSNetWorx for ControlNet
Compliance & Industry Standards
- ControlNet International (CI) Specification — Compliant with ControlNet Specification Version 2.0, ensuring interoperability with all certified ControlNet devices.
- UL 508 — Listed for industrial control equipment.
- CE Marking — Meets EU Low Voltage Directive (LVD) and EMC Directive requirements for European market deployment.
- cUL — Canadian certification per CSA standards.
- IEC 60874-10 — ST fiber connector standard compliance.
- RoHS Compliant — Restriction of Hazardous Substances Directive (EU 2011/65/EU).
Quality Assurance & Sourcing
Konmask.com sources the 1786-RPFM through verified industrial automation distributors and authorized channel partners. Every unit offered is subject to the following quality controls:
- Authenticity Verification — Units are inspected for genuine Rockwell Automation labeling, date codes, and holographic seals prior to listing.
- Functional Testing — Where applicable, units undergo power-on and communication link verification before shipment.
- Condition Disclosure — Product condition (new, surplus-new, or refurbished) is explicitly stated on each listing. Contact us to confirm current stock condition.
- Traceability — Lot and serial number records are maintained for all stocked units to support your incoming inspection and MRO documentation requirements.
- Warranty — Konmask provides a limited warranty on all shipped units. Contact support for warranty terms applicable to your order.
How to Source This Part
To place an order or request a quote for the Allen-Bradley 1786-RPFM:
- Add to Cart — Use the button above for immediate checkout with standard lead times.
- Request a Quote — Email support@konmask.com with your required quantity, delivery timeline, and destination country for a tailored commercial offer.
- Bulk / Project Orders — For system integrators and EPC contractors sourcing multiple ControlNet components, contact us for project pricing and consolidated shipment options.
- Urgent Requirements — Call or WhatsApp +0086 19859288691 for expedited sourcing on critical plant shutdowns or emergency replacements.
- Export & Cross-Border — Konmask ships internationally. Provide your destination and we will advise on applicable export documentation, duties, and lead times.
Application-Specific FAQ
Q: Can the 1786-RPFM be used to connect two separate ControlNet networks?
A: No. The 1786-RPFM is a repeater, not a bridge or router. It extends a single ControlNet network segment over fiber; it does not route traffic between two independent ControlNet networks. Use a ControlNet bridge module for inter-network connectivity.
Q: What is the maximum number of 1786-RPFM repeaters allowed in a single ControlNet ring?
A: Rockwell Automation specifies a maximum of 5 repeaters in series on a single ControlNet segment. Consult publication CNET-UM001 for topology planning guidelines.
Q: Is the 1786-RPFM compatible with ControlNet redundant media (1786-RPCD)?
A: The 1786-RPFM is designed for single-channel fiber ring topology. For redundant media applications, evaluate the 1786-RPCD (coax) or consult Rockwell’s media planning guide for your specific redundancy architecture.
Q: Does this repeater require configuration in RSNetWorx?
A: The 1786-RPFM is transparent to the ControlNet network and does not require node address assignment or RSNetWorx configuration. It is plug-and-play within the physical layer.
Q: What fiber cable specification is required?
A: Use 62.5/125 µm multimode fiber with ST connectors. Single-mode fiber is not supported by the 1786-RPFM. Ensure fiber runs meet the maximum attenuation budget specified in Rockwell publication 1786-IN009.
Q: Can Konmask supply the complete ControlNet fiber ring BOM?
A: Yes. Contact support@konmask.com with your network topology drawing and we will prepare a consolidated parts list and quotation.
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