Configured for ControlNet network data communication in ControlLogix systems, the Allen-Bradley 1756-CN2 (1756-CN2 Communication Module) provides direct network interface execution between Logix controllers, I/O devices, and connected ControlNet nodes.

Model Identification

The 1756-CN2 is a ControlLogix communication module designed for ControlNet standard media networks. It provides scheduled and unscheduled communication services between ControlLogix processors and connected network devices.

• Catalog Number: 1756-CN2
• Series: ControlLogix
• Network Type: ControlNet
• Media Type: Standard Media
• Communication Rate: 5 Mbps
• Logix Connections: 128
• Maximum Nodes: 99

Hardware Specifications

ControlLogix Network Communication Characteristics

The 1756-CN2 integrates ControlLogix chassis with ControlNet deterministic communication networks. The module exchanges controller, I/O, and messaging data through the ControlNet protocol structure.

The ControlLogix backplane interface manages communication between the 1756-CN2 module and the processor chassis. Network configuration requires compatible ControlNet scheduling, node addressing, and firmware compatibility between connected devices.

Ordering Information

• 1 x Allen-Bradley 1756-CN2 ControlLogix ControlNet Communication Module
• 1 x Protective industrial packaging
• Documentation availability depends on supply configuration

Field Installation Guidelines

• Install the module in a compatible ControlLogix chassis slot.
• Remove chassis power before module installation or removal unless the system configuration specifically supports removal under power.
• Verify ControlNet node addressing before network startup.
• Use approved ControlNet cabling and connectors for network connections.
• Maintain separation between communication cables and high voltage wiring.
• Confirm controller firmware compatibility before commissioning.

Frequently Asked Questions

• What communication protocol does the 1756-CN2 support?

The 1756-CN2 supports ControlNet communication and provides network connectivity between ControlLogix controllers and ControlNet devices.

• What is the communication speed of the 1756-CN2?

The module operates at a ControlNet communication rate of 5 Mbps according to the provided technical specification.

• How many Logix connections are supported by this module?

The 1756-CN2 supports up to 128 Logix connections for communication between configured ControlLogix network devices.

• How many ControlNet nodes can be connected?

The module supports a maximum of 99 ControlNet nodes within the configured network architecture.

• Does the 1756-CN2 use Ethernet communication?

No. The 1756-CN2 is a ControlNet communication module and does not provide EtherNet/IP network functionality.

• Where is the 1756-CN2 installed in a ControlLogix system?

The module is installed in a ControlLogix chassis and communicates with the processor through the chassis backplane.

• Does the module require firmware compatibility checks?

Yes. The communication module firmware should be compatible with the ControlLogix processor and ControlNet configuration software.

• Can the module be removed while powered?

Installation or removal should follow ControlLogix chassis procedures. Power removal is recommended unless the configured system specifically permits live module handling.