1769-L35CR CompactLogix Controller with Dual ControlNet Ports

Product Overview

The Allen-Bradley 1769-L35CR is a CompactLogix ControlNet processor manufactured by Rockwell Automation. It combines 1.5 MB of memory with serial communication and dual ControlNet network interfaces.

The 1769-L35CR CompactLogix controller supports up to 30 Compact I/O modules across three I/O banks. It provides an RS-232 serial port for compatible programming and device communication.

Its Channel A and Channel B interfaces support compatible ControlNet network configurations. A Network Access Port (NAP) also provides local access to supported network equipment.

This processor suits industrial control systems that require CompactLogix processing and ControlNet communication. Always verify the controller revision, project configuration, and I/O compatibility before installation.

Technical Specifications

Specification note: Confirm the exact hardware revision and installation requirements against the applicable Rockwell Automation documentation.

Core Features and Technical Benefits

• ControlNet connectivity: Channel A and Channel B support compatible ControlNet network configurations.
• Serial communication: The RS-232 interface supports DF1 and ASCII communication with compatible devices.
• Compact I/O expansion: The controller supports up to 30 Compact I/O modules across three I/O banks.
• Local network access: The NAP supports compatible local ControlNet access equipment.
• Compact controller architecture: The module combines processing, memory, and communication interfaces in one unit.

Typical Industrial Applications

• Manufacturing automation: Coordinate machine sequences and distributed input/output signals.
• Packaging equipment: Exchange control data between compatible controllers and I/O stations.
• Material handling: Support conveyor control and compatible field device communication.
• Process support systems: Connect compatible equipment through an established ControlNet network.
• Control system maintenance: Replace matching processors in existing CompactLogix installations.

Installation Guide

1. Verify the catalog number: Match the complete 1769-L35CR designation and required hardware revision.
2. Isolate electrical power: Follow site lockout procedures before removing or installing controller hardware.
3. Check mounting: Secure the processor using a compatible DIN rail or panel mounting arrangement.
4. Verify power capacity: Check the 5 VDC backplane current budget and each I/O bank power supply.
5. Inspect cables: Confirm the correct RS-232 and ControlNet cables for the intended connections.
6. Check wiring: Verify conductor sizes, terminal requirements, insulation ratings, and grounding practices.
7. Load the project: Confirm programming software compatibility and controller configuration.
8. Complete functional tests: Check controller status, network communication, and I/O response before production.

Do not assume that every CompactLogix module or expansion cable supports this processor. Verify the applicable hardware compatibility documentation before modifying the system.

Commissioning, Diagnostics, and Maintenance

• Startup checks: Review controller status indicators and compare them with the hardware manual.
• ControlNet faults: Inspect cables, connectors, node configuration, and network status.
• Serial communication faults: Check the protocol, port settings, cable pinout, and connected device configuration.
• I/O errors: Inspect module seating, bank power supplies, and expansion connections.
• Intermittent faults: Compare fault logs with power interruptions and network disturbances.
• Preventive maintenance: Inspect cabinet temperature, ventilation, cable condition, and mounting security.

Field example: A machine reports missing I/O data after cabinet maintenance. An engineer checks bank power, expansion connections, and controller diagnostics before replacing the processor.

If ControlNet communication fails, inspect the network cable and node configuration first. Replacing the processor without checking the network may not resolve the fault.

Compatibility and Selection Guide

• Catalog number: Confirm the full 1769-L35CR designation against the installed module.
• Hardware revision: Verify the required Series A or Series B revision.
• Network requirements: Check the ControlNet topology and required communication interfaces.
• Serial requirements: Confirm the required DF1 or ASCII communication configuration.
• I/O configuration: Check module compatibility, bank power requirements, and expansion cable limitations.
• Programming software: Verify project compatibility and the required communication drivers.
• Replacement planning: Back up the controller project and document the existing configuration before removal.

The listed interfaces do not guarantee compatibility with every Logix controller family. Confirm the complete system architecture before ordering a replacement.

Environmental and Electrical Considerations

• Temperature: The supplied specifications list an operating range of 0°C to 60°C.
• Storage: The stated storage range is -40°C to 85°C.
• Humidity: Maintain 0–95% relative humidity without condensation.
• Vibration and shock: Verify the stated ratings and test conditions against the applicable hardware manual.
• Wiring: Use suitable copper conductors and follow terminal and installation requirements.
• Interference control: Follow manufacturer guidance for grounding, shielding, cable routing, and network installation.

Measurement parameters: Measurement range, sensitivity, linearity, and resolution do not directly define this processor's primary function. Select compatible analog or measurement modules according to the actual field signal requirements.

Certification: Verify applicable approvals and compliance documentation for the exact catalog number and hardware revision. Do not assume certifications without supporting manufacturer documentation.

Packaging and Shipping

• 1 × Allen-Bradley 1769-L35CR processor module, according to the confirmed order.
• Additional accessories and documentation only when explicitly included in the order.

• Shipping carriers: FedEx, UPS, and DHL, subject to destination and service availability.
• Processing time: Shipment processing within 24–48 hours after order confirmation, subject to stock verification.
• Packaging: Protective packaging suitable for transportation.

Contact our team to confirm stock, included accessories, packaging details, and shipping arrangements before ordering.

Warranty and Technical Support

Global PLC Spare HUB provides a 12-month warranty under its applicable sales terms. Contact our team to confirm coverage, claim procedures, and technical support arrangements.

Our team can help verify the catalog number, communication interfaces, I/O expansion requirements, and replacement suitability before purchase.

For faster assistance, provide the existing module label, hardware revision, application details, and destination country when requesting a quotation.

Global PLC Spare HUB's Insight

From a field engineering perspective, replacement risks often involve system compatibility rather than memory capacity alone.

For example, a machine may depend on an existing RS-232 programming connection and both ControlNet interfaces. A visually similar processor may not provide the required communication arrangement.

Engineers should also verify the I/O bank power budget before expanding a system. Excessive electrical demand can cause configuration problems or unexpected faults.

Before replacement, save the controller project and record network settings. After installation, validate controller status, network communication, and field I/O operation before restarting production.

Frequently Asked Questions

Q1: What is the main function of the Allen-Bradley 1769-L35CR?

The 1769-L35CR is a CompactLogix processor with 1.5 MB of memory, RS-232 serial communication, and ControlNet interfaces.

Q2: How many Compact I/O modules can the 1769-L35CR support?

It supports up to 30 Compact I/O modules across as many as three I/O banks. Verify expansion cable and power supply compatibility before installation.

Q3: Can I replace an existing processor directly with the 1769-L35CR?

Check the project, hardware revision, communication settings, I/O layout, and software compatibility first. A matching catalog number alone does not guarantee a successful replacement.

Q4: What should I check if ControlNet communication fails?

Inspect network cables, connectors, node configuration, and controller status indicators. Review available diagnostics before deciding whether to replace the processor.

Q5: Why should I check the I/O power budget?

Each I/O bank requires a suitable power supply. Check module current requirements to avoid exceeding available power capacity.

Q6: What information helps confirm the correct replacement?

Provide the full catalog number, hardware revision, existing controller configuration, communication requirements, and product label photos when available.

Q7: What warranty and shipping options are available?

Global PLC Spare HUB offers a 12-month warranty under applicable terms. FedEx, UPS, and DHL options are available, with processing targeted within 24–48 hours after order confirmation.

Q8: How can I reduce commissioning problems after replacement?

Back up the project and document network settings before removal. After installation, check controller status, communication links, I/O response, and application operation.

Q9: What should I do if the controller powers up but the application does not run correctly?

Check controller diagnostics, project configuration, communication status, and I/O faults. Compare the loaded project with the approved backup before changing hardware.

Q10: What should I confirm before requesting a quotation?

Confirm the catalog number, hardware revision, required interfaces, I/O configuration, and destination country. Contact Global PLC Spare HUB to check pricing, availability, and compatibility.

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