Description
Overview
The Allen-Bradley 1756-CNBR/E is a high-performance ControlNet Bridge module from the Series E hardware generation, specifically designed for the ControlLogix automation platform. This module facilitates deterministic communication between ControlLogix processors and remote I/O chassis, providing essential media redundancy to maintain network integrity. By utilizing dual communication channels, the 1756-CNBR/E ensures that scheduled I/O data and unscheduled messaging persist even in the event of a localized cable failure or tap disconnection.
Features
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Media Redundancy: Dual-channel architecture allows for instantaneous failover between coaxial lines, preventing system downtime during physical network faults.
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Deterministic Throughput: Maintains a constant 5 Mbps data rate, critical for time-sensitive control applications.
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Scalable Architecture: Supports up to 99 nodes on a single ControlNet segment, with a capacity for 64 concurrent system connections.
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Logix Integration: Provides 40 to 48 dedicated Logix communication connections and 20 buffers for unconnected messaging, ensuring efficient data handling.
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Flexible Configuration: Features two BNC coaxial ports for redundant media and one RJ45 port for supplemental connectivity.
Technical Specifications
| Model |
1756-CNBR/E |
| Series |
Series E |
| Communication Rate |
5 Mbps |
| Max Node Capacity |
99 Nodes |
| Max Connections |
64 |
| Backplane Current (5.1V) |
970 mA |
| Backplane Current (24V) |
1.7 mA |
| Power Dissipation |
5.5 Watts |
| Operating Temperature |
0 to 60 degC |
| Isolation Voltage |
30V (Basic Insulation) |
Installation Guidelines
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ESD Protection: Always utilize a grounded wrist strap or similar ESD-preventative measures when handling the module to prevent damage to sensitive internal circuitry.
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Chassis Seating: The module occupies a single slot in a standard 1756 ControlLogix chassis. Ensure the module is fully seated and the top/bottom retaining latches are locked before applying power.
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Power Requirements: Verify that the chassis power supply is rated to handle the additional 5.5W load of the module.
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Cable Management: Use 1786-RG6 quad-shield coaxial cabling. Ensure cables are routed away from high-voltage lines or high-EMI sources to maintain signal integrity.
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Redundancy Setup: When implementing redundancy, ensure both channel A and channel B are connected to independent trunk lines to maximize fault tolerance.
FAQ
Does this module require a specific firmware version?
The 1756-CNBR/E Series E hardware is generally compatible with standard ControlLogix firmware revisions; however, always verify compatibility with your specific controller firmware version via the Studio 5000 or RSLogix 5000 software environment.
Can this module be hot-swapped?
Yes, the ControlLogix system supports Removal and Insertion Under Power (RIUP). Ensure the area is non-hazardous and proper safety protocols are followed before removing or inserting the module into an active chassis.
