Allen-Bradley 1756-CNBR/E ControlNet Communications Bridge – ControlLogix Series E
Imagine a large-scale automotive assembly line where dozens of ControlLogix controllers must exchange real-time I/O data and interlocking signals across multiple ControlNet segments. Without a reliable bridge module, each network segment becomes an isolated island — production halts, safety interlocks fail to propagate, and engineers face hours of manual fault-tracing across hundreds of nodes. The Allen-Bradley 1756-CNBR/E eliminates this risk by seamlessly bridging ControlNet segments within the ControlLogix backplane, ensuring deterministic, high-speed communication that modern industrial automation demands.
The 1756-CNBR/E is the Series E revision of Rockwell Automation’s ControlNet bridge module for the 1756 ControlLogix platform — one of the most widely deployed programmable automation controller (PAC) families in the world. As a bridge (not a scanner), it extends ControlNet network reach without consuming controller memory, making it the preferred choice for large distributed architectures in automotive, oil & gas, water treatment, and heavy manufacturing. Its global installed base and long product lifecycle make it a cornerstone component in mission-critical control systems across North America, Europe, and Asia-Pacific.
Technical Specifications
- Part Number: 1756-CNBR/E
- Series: E
- Platform: Allen-Bradley ControlLogix 1756
- Network: ControlNet (IEEE 802.3 coaxial / fiber)
- Module Type: ControlNet Communications Bridge
- Backplane Current Draw: Refer to Rockwell Automation publication 1756-TD001
- Operating Temperature: 0°C to 60°C (32°F to 140°F)
- Storage Temperature: -40°C to 85°C (-40°F to 185°F)
- Relative Humidity: 5% to 95% non-condensing
- Weight: Approx. 400 g
- Certifications: UL, CE, C-Tick (verify current listings with Rockwell Automation)
- Firmware: Field-upgradeable via RSLogix 5000 / Studio 5000
Note: All specifications above are based on published Rockwell Automation documentation. Konmask.com does not fabricate or alter OEM specifications.
Key Features & Benefits
- Transparent Bridging: Bridges two ControlNet segments without consuming controller scan time or memory — ideal for large, distributed architectures.
- Deterministic Communication: ControlNet’s scheduled (NUT-based) communication ensures predictable, repeatable data transfer for time-critical I/O.
- Series E Reliability: Latest hardware revision incorporating Rockwell’s accumulated field improvements for enhanced EMI tolerance and long-term stability.
- Hot-Swap Capable: Supports removal and insertion under power (RIUP) within the ControlLogix chassis — minimizing planned downtime.
- Dual-Port ControlNet: Supports redundant media (coax A/B) for fault-tolerant network topologies.
- Wide Industry Acceptance: Fully compatible with RSNetWorx for ControlNet scheduling tools and integrates with Rockwell’s Integrated Architecture ecosystem.
- Long Service Life: Designed for 24/7 continuous operation in harsh industrial environments.
Industry & Equipment Applications
- Automotive Manufacturing: Body-in-white welding lines, paint shop conveyors, and powertrain assembly requiring multi-segment ControlNet bridging.
- Oil & Gas: Pipeline SCADA systems and offshore platform control where network segmentation and redundancy are mandatory.
- Water & Wastewater Treatment: Distributed pump station control with geographically separated ControlNet segments.
- Food & Beverage: High-speed packaging lines where deterministic I/O timing is critical for product quality.
- Power Generation: Turbine control and substation automation requiring reliable inter-segment communication.
- Mining & Metals: Conveyor systems and smelting process control with extended network distances.
System Integration & Compatible Parts
The 1756-CNBR/E is designed to operate within the broader Allen-Bradley ControlLogix ecosystem. Compatible and commonly paired components include:
- 1756-CN2/B, 1756-CN2R/B — ControlNet Scanner modules (redundant media)
- 1756-A7, 1756-A10, 1756-A13, 1756-A17 — ControlLogix chassis (7, 10, 13, 17 slots)
- 1756-PA72, 1756-PB72 — ControlLogix power supplies (AC/DC)
- 1756-L71, 1756-L72, 1756-L73, 1756-L74, 1756-L75 — ControlLogix 5570 controllers
- 1756-L81E, 1756-L82E, 1756-L83E, 1756-L84E, 1756-L85E — ControlLogix 5580 controllers
- 1786-RPA, 1786-RPCD — ControlNet repeaters for extended cable runs
- 9324-RLD300ENE — RSNetWorx for ControlNet (network scheduling software)
Contact Konmask.com for cross-reference assistance and bill-of-materials (BOM) support.
Our Quality Assurance Process
At Konmask.com, every Allen-Bradley module undergoes a rigorous multi-stage verification process before shipment:
- Visual Inspection: Physical examination for damage, counterfeit indicators, and label authenticity.
- Firmware Verification: Firmware version confirmed against Rockwell Automation’s published revision history.
- Functional Test (where applicable): Modules are bench-tested in a live ControlLogix chassis to verify backplane communication and ControlNet port activity.
- Traceability Documentation: Each unit is logged with serial number, source, and test date for full supply chain traceability.
- Anti-Static Packaging: Shipped in ESD-safe bags with foam cushioning to prevent transit damage.
How to Order
- Submit an inquiry via the “Request a Quote” button on this page, or email [email protected].
- Provide your required quantity, delivery timeline, and destination country.
- Our team will respond within 1 business day with pricing, lead time, and availability confirmation.
- Upon order confirmation, we issue a proforma invoice and arrange shipment via DHL, FedEx, or UPS with full tracking.
- Post-delivery technical support is available for integration and commissioning questions.
Why Choose Konmask.com?
- Specialized Inventory: We focus exclusively on industrial automation components — Allen-Bradley, Siemens, Schneider, ABB, and more.
- Global Reach: Serving B2B buyers in 40+ countries with export documentation support (CO, packing list, commercial invoice).
- Technical Expertise: Our team includes experienced automation engineers who can advise on compatibility and system design.
- Competitive Pricing: Direct sourcing relationships enable us to offer market-competitive pricing on both new and refurbished units.
- Fast Response: Dedicated account managers ensure inquiries are handled promptly — no automated bots, real engineers.
- Secure Transactions: T/T, L/C, and other B2B payment terms available for qualified buyers.
Frequently Asked Questions
Q: What is the difference between the 1756-CNBR/E and earlier series (A, B, C, D)?
A: The /E suffix denotes the Series E hardware revision, which incorporates Rockwell Automation’s latest component and firmware improvements. Series E offers enhanced EMI tolerance and is the currently recommended revision for new installations. Earlier series remain functionally compatible but may have limited firmware update support.
Q: Is the 1756-CNBR/E a scanner or a bridge?
A: It is a bridge, not a scanner. It connects two ControlNet segments at the network layer without consuming controller I/O tree resources. If you need a ControlNet scanner (to own I/O on the network), you need the 1756-CN2 or 1756-CN2R module instead.
Q: Can the 1756-CNBR/E be used with ControlLogix 5580 (L8x) controllers?
A: Yes. The 1756-CNBR/E is backplane-agnostic and compatible with all ControlLogix chassis generations, including those housing 5580 series controllers, provided the chassis and power supply are correctly sized.
Q: Do you supply new or refurbished units?
A: Konmask.com supplies both new (factory-sealed) and professionally refurbished units. Condition is clearly stated in the quotation. All refurbished units pass our functional test protocol.
Q: What is the lead time for the 1756-CNBR/E?
A: Lead time varies by stock availability. In-stock units typically ship within 3–5 business days. For out-of-stock items, lead time is quoted individually. Contact us for real-time availability.
Q: Can you provide export documentation for customs clearance?
A: Yes. We provide commercial invoice, packing list, and certificate of origin (CO) as standard. Additional documentation (e.g., MSDS, test reports) can be arranged upon request.
© 2026 Konmask.com. All rights reserved.
Original Source: https://Konmask.com
Contact: [email protected] | +0086 19859288691








