1756-CN2R | Allen-Bradley Redundant ControlNet Module for ControlLogix Chassis
1756-CN2R | Allen-Bradley Redundant ControlNet Module for ControlLogix Chassis
1756-CN2R | Allen-Bradley Redundant ControlNet Module for ControlLogix Chassis
    1756-CN2R | Allen-Bradley Redundant ControlNet Module for ControlLogix Chassis
1756-CN2R | Allen-Bradley Redundant ControlNet Module for ControlLogix Chassis

1756-CN2R | Allen-Bradley Redundant ControlNet Module for ControlLogix Chassis

Part #: 1756-CN2R Manufactured by: Allen-Bradley
Regular price
$899.00
Sale price
$899.00
Regular price
3 in Stock
Condition: New – Open box
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Product Overview
The Allen-Bradley 1756-CN2R is a ControlNet communication module that is part of the ControlLogix product family. This mod...  Read more
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Product Description P/N: 1756-CN2R

Description / Specifications

Description 

The Allen-Bradley 1756-CN2R is a ControlLogix communication module designed to establish ControlNet connectivity within distributed and redundant automation networks. It supports dual BNC ControlNet interfaces operating at 5 Mbps and includes a USB port for local configuration. With capacity for up to 128 Logix connections, the module enables high-performance, deterministic communication in large industrial systems.

 

 

Technical Specifications 

Condition New/Never Used Surplus
Brand Allen-Bradley
Category Communication Modules
Part Number 1756-CN2R
Subcategory ControlLogix ControlNet Modules
Series ControlLogix
Module Type Bridge / Communication Module
ControlNet Ports Two (2) BNC ControlNet ports
USB Port USB 1.1, 12 Mbps
ControlNet Data Rate 5 Mbps
Maximum Logix Connections 128
Maximum Total Connections 131
Maximum Nodes 99
Backplane Current Draw 1.3 A at 5.1 VDC; 3 mA at 24 VDC
Isolation Voltage 30 VDC continuous; tested at 500 VAC for 1 minute
Thermal Dissipation 22.9 BTU/hr
Operating Temperature 0 to 60 °C (32 to 140 °F)
Humidity 5–95% non-condensing
Shock Rating 30 G
Vibration Rating 2 G, 10–500 Hz
Compatible Chassis All 1756 ControlLogix chassis
Compatible Power Supplies 1756-PA72, PA75, PB72, PB75, PC75, PH75; redundant: PA75R, PB75R, PSCA2
Weight 0.293 kg (0.64 lb)

 

 

Information About 1756-CN2R

The 1756-CN2R is part of the ControlLogix platform and is built to provide redundant ControlNet communication within modular Logix architectures. It installs into any standard ControlLogix chassis and is compatible with both standard and redundant 1756 power supplies. The module supports a multi-node coaxial network structure using approved RG6 cabling, allowing long-distance I/O distribution and integration with HMIs and SCADA systems. Designed with robust isolation, wide temperature capability, and full-speed USB configuration support, it meets the demands of continuous industrial communication.

Key Features:

  • Redundant ControlNet Ports: Dual BNC connections support redundant coaxial network paths for fault-tolerant operation.
  • High Connection Capacity: Supports up to 128 Logix connections and 131 total communication connections.
  • Fast Network Throughput: Operates at 5 Mbps for deterministic industrial control communication.
  • USB Configuration Port: Full-speed 12 Mbps USB provides convenient local module setup.
  • Chassis Flexibility: Installs into any ControlLogix chassis with a single slot width.
  • Wide Environmental Ratings: Operates from 0 to 60 °C with 30 G shock resistance and 2 G vibration tolerance.
  • Industry-Standard Cabling: Uses 1786-RG6 quad-shield coax for ControlNet trunk and drop connections.
  • High Node Capacity: Supports up to 99 nodes per ControlNet segment for extensive distributed architectures.

The 1756-CN2R delivers the reliability and precision required for secure industrial networking and coordinated multi-device communication.

Frequently Asked Questions about 1756-CN2R
Question: How does the 1756-CN2R support ControlNet network communication?
Date Update:03/06/2025
Answer:

The module uses two (2) BNC ControlNet ports that operate at 5 Mbps, enabling real-time deterministic control and peer-to-peer communication. It can connect up to 99 nodes and supports a redundant configuration to enhance network reliability. Additionally, it uses 1786-RG6 quad-shielded coaxial cables to ensure reliable network performance over long distances. This makes it suitable for complex industrial automation systems.

Question: Which ControlLogix power supplies are compatible with the 1756-CN2R?
Date Update:03/06/2025
Answer:

The module is compatible with both standard and redundant ControlLogix power supplies. Supported standard supplies include:

  • 1756-PA72/C
  • 1756-PA75/B
  • 1756-PB72/C
  • 1756-PB75/B
  • 1756-PC75/B
  • 1756-PH75/B

Supported redundant power supplies include:

  • 1756-PA75R
  • 1756-PB75R
  • 1756-PSCA2

These options provide flexibility in system design and ensure uninterrupted operation in critical applications.

Question: What are the power requirements of the 1756-CN2R module?
Date Update:03/06/2025
Answer:

The module draws 1.3 A at 5.1 VDC and 3 mA at 24 VDC from the backplane. It dissipates up to 22.9 BTU/hr of heat during operation. The module’s design ensures reliable operation within the specified voltage and power ranges. Proper power supply selection and chassis configuration are essential for optimal performance. Always adhere to the recommended installation guidelines.

Question: What is the maximum number of Logix connections supported by the 1756-CN2R?
Date Update:03/06/2025
Answer:

The 1756-CN2R supports up to 128 Logix communication connections and 131 total network connections. This capacity allows it to handle complex distributed I/O and peer-to-peer communication tasks. It ensures that large systems can maintain reliable data exchange between controllers and devices. Proper network design is crucial to avoid exceeding these limits.

Question: Does the 1756-CN2R remain available for purchase?
Date Update:03/06/2025
Answer:

Yes, the 1756-CN2R currently holds an Active Mature lifecycle status, meaning it is still available for purchase and supported by Rockwell Automation. This indicates it is recommended for existing systems but may be approaching the end of its lifecycle.

IQElectro is not an authorized distributor.
IQElectro LLC (IQElectro) is NOT an Authorized Distributor or in any way affiliated with Rockwell Automation, Siemens, or any other Manufacturers. IQElectro is NOT an Authorized Dealer of this product. The product may be of older version, date codes, or design than that available from authorized dealers. As IQElectro is not an authorized dealer of this product, the Original Manufacturer's Warranty and Support DO NOT apply. IQElectro sells SURPLUS only and DOES NOT SELL SOFTWARE or FIRMWARE licenses For more detailed information, please refer to the full version of our disclaimer policy Disclaimer Policy.
Description / Specifications

Description 

The Allen-Bradley 1756-CN2R is a ControlLogix communication module designed to establish ControlNet connectivity within distributed and redundant automation networks. It supports dual BNC ControlNet interfaces operating at 5 Mbps and includes a USB port for local configuration. With capacity for up to 128 Logix connections, the module enables high-performance, deterministic communication in large industrial systems.

 

 

Technical Specifications 

Condition New/Never Used Surplus
Brand Allen-Bradley
Category Communication Modules
Part Number 1756-CN2R
Subcategory ControlLogix ControlNet Modules
Series ControlLogix
Module Type Bridge / Communication Module
ControlNet Ports Two (2) BNC ControlNet ports
USB Port USB 1.1, 12 Mbps
ControlNet Data Rate 5 Mbps
Maximum Logix Connections 128
Maximum Total Connections 131
Maximum Nodes 99
Backplane Current Draw 1.3 A at 5.1 VDC; 3 mA at 24 VDC
Isolation Voltage 30 VDC continuous; tested at 500 VAC for 1 minute
Thermal Dissipation 22.9 BTU/hr
Operating Temperature 0 to 60 °C (32 to 140 °F)
Humidity 5–95% non-condensing
Shock Rating 30 G
Vibration Rating 2 G, 10–500 Hz
Compatible Chassis All 1756 ControlLogix chassis
Compatible Power Supplies 1756-PA72, PA75, PB72, PB75, PC75, PH75; redundant: PA75R, PB75R, PSCA2
Weight 0.293 kg (0.64 lb)

 

 

Information About 1756-CN2R

The 1756-CN2R is part of the ControlLogix platform and is built to provide redundant ControlNet communication within modular Logix architectures. It installs into any standard ControlLogix chassis and is compatible with both standard and redundant 1756 power supplies. The module supports a multi-node coaxial network structure using approved RG6 cabling, allowing long-distance I/O distribution and integration with HMIs and SCADA systems. Designed with robust isolation, wide temperature capability, and full-speed USB configuration support, it meets the demands of continuous industrial communication.

Key Features:

  • Redundant ControlNet Ports: Dual BNC connections support redundant coaxial network paths for fault-tolerant operation.
  • High Connection Capacity: Supports up to 128 Logix connections and 131 total communication connections.
  • Fast Network Throughput: Operates at 5 Mbps for deterministic industrial control communication.
  • USB Configuration Port: Full-speed 12 Mbps USB provides convenient local module setup.
  • Chassis Flexibility: Installs into any ControlLogix chassis with a single slot width.
  • Wide Environmental Ratings: Operates from 0 to 60 °C with 30 G shock resistance and 2 G vibration tolerance.
  • Industry-Standard Cabling: Uses 1786-RG6 quad-shield coax for ControlNet trunk and drop connections.
  • High Node Capacity: Supports up to 99 nodes per ControlNet segment for extensive distributed architectures.

The 1756-CN2R delivers the reliability and precision required for secure industrial networking and coordinated multi-device communication.

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