1769-CRL1 | Allen-Bradley | Compact I/O 1-Foot Right-to-Left Bus Expansion Cable

Module Overview

The 1769-CRL1 is a specialized bus expansion cable designed for the Allen-Bradley CompactLogix and MicroLogix 1500 systems. This 1-foot (0.3-meter) interconnect is engineered to extend the 1769 communication backplane from the right end of one I/O bank to the left end of a subsequent bank. It is a critical component for multi-rack configurations, allowing engineers to split I/O modules across two separate DIN rails within the same enclosure or across adjacent cabinets while maintaining high-speed data synchronization with the controller.

Detailed Engineering Specifications

The 1769-CRL1 is built to handle the high current demands of a fully populated expansion rack, ensuring signal integrity across the extended bus.

• Connection Orientation: Right-to-Left (End of Bank 1 to Start of Bank 2)

• Cable Length: 1 Foot (0.30 Meters)

• Backplane Current (24V DC): 1.4 Amperes

• Power Consumption: 33.6 Watts

• Power Dissipation: 7.5 Watts

• Isolation Voltage: 30V Continuous

• Operating Temperature: 0°C to 60°C (32°F to 140°F)

• Storage Temperature: -40°C to 85°C (-40°F to 185°F)

• Vibration Resistance: 5G @ 10 to 500 Hz

• Shock Resistance: 30G (Operating)

• Physical Weight: 0.63 lbs (0.28 kg)

• Compatibility: 1769 Compact I/O Modules / CompactLogix Controllers

System Architecture and Expansion Rules

When utilizing the 1769-CRL1, it is vital to adhere to the "Bank" architecture of the 1769 platform. An expansion cable does not provide power to the second rack; it only extends the communication bus. Therefore, each expansion bank connected via a 1769-CRL1 must have its own 1769 power supply (such as a 1769-PA2 or 1769-PB4). The system supports a maximum of two expansion cables, allowing for a total of three banks (the local controller bank plus two expansion banks).

Installation Best Practices

The cable features heavy-duty connectors with integrated locking mechanisms to prevent accidental disconnection in high-vibration environments. Because the 1769-CRL1 is a "Right-to-Left" cable, it must be plugged into the right-side bus interface of the first rack and the left-side bus interface of the second rack. Attempting to force the connection in a different orientation can damage the delicate pins of the 1769 backplane.

Technical FAQ

Can I use the 1769-CRL1 to connect a rack that is 3 feet away?

No. The 1769-CRL1 is strictly 1 foot long. If your racks are further apart, you must use the 1769-CRR3 (3-foot Right-to-Right/Left-to-Left) or the 1769-CRL3 (3-foot Right-to-Left) depending on your physical layout.

Does the expansion cable count as a "module" toward the power supply distance rating?

No. The cable itself does not occupy a logical slot or impact the distance rating of the modules. However, the modules in the new bank must still be within the required distance of the new power supply installed in that bank.

Is the cable hot-swappable?

Absolutely not. Disconnecting the 1769-CRL1 while the system is powered will cause an immediate major fault on the controller and could result in hardware damage due to the 1.4A current flowing through the bus.