The Allen-Bradley 1769-L35CR, also cataloged as the 1769-L35CR Programmable Automation Controller, operates as a dedicated hardware component for deterministic ControlNet process execution and logic control within industrial automation platforms.

Model Suffix and Designator

The 1769-L35CR controller is an integrated hardware solution featuring 1.5 MB of onboard memory. The "CR" suffix designates the support for redundant ControlNet connectivity, providing channel-level media redundancy for mission-critical industrial I/O communication.

Hardware Specifications

Deterministic Network Connectivity

This controller manages backplane bus communication velocity and supports firmware flash compatibility for system maintenance. Its architecture allows for precise I/O density scaling, supporting up to 30 Compact I/O modules. Deterministic network performance is maintained through adherence to specific ControlNet scheduling parameters and node addressing conventions.

Ordering Information

• 1 x 1769-L35CR ControlNet Controller.

• 1 x 1769-ECR End Cap.

• Note: Communication cables, programming software, and ControlNet tap cables are supplied as separate catalog items.

Field Installation Guidelines

• Mounting: Install on a standard 35 mm DIN rail or panel surface. Ensure vertical orientation to maintain convective heat dissipation paths.

• Grounding: Connect the chassis ground lug to a clean earth point using a 2.5 mm squared conductor to mitigate common-mode noise.

• Communication: Utilize 75-ohm coaxial cabling for ControlNet ports; ensure high-frequency shielding is properly grounded at the tap level.

• Cabling: Maintain physical isolation between low-voltage serial interfaces and high-current power distribution wiring to prevent crosstalk.

Logistical Dispatch Details

• Delivery time: 2-7 days when payment finish.

• Shipment via DHL/FEDEX/UPS.

• All units are secured in anti-static industrial packaging to ensure mechanical integrity and protect against electrostatic discharge during transit.

Frequently Asked Technical Queries

• Does the unit support hot-swapping?

  The 1769-L35CR does not support hot-swapping. All power must be removed from the chassis backplane before inserting or removing the controller. Live insertion will cause high-voltage transients on the backplane pins.

• How is ControlNet redundancy configured?

  Redundancy is handled via the primary and channel B ports. The network topology must be configured for redundant media, and the scheduling parameters must be synchronized across all nodes to ensure seamless transition.

• What is the maximum I/O module capacity?

  The controller supports up to 30 Compact I/O modules across the local bus. Exceeding this limit will trigger an I/O bus communication fault, as the power supply and backplane bandwidth cannot support additional nodes.

• How is firmware flash managed?

  Firmware updates are performed via the serial or network port. The process requires a stable power source. Failure to maintain power during the flash sequence will corrupt the bootloader, rendering the CPU unresponsive.

• Is the RS-232 port isolated?

  The RS-232 port is intended for point-to-point configuration and ASCII serial communication. It is not galvanically isolated; therefore, use of an external serial isolator is recommended when connecting to remote equipment.

• How is the memory segmented?

  The 1.5 MB memory is partitioned for user logic, data tables, and communication buffers. Monitoring memory consumption is necessary to avoid "out of memory" errors during online edits or heavy I/O polling operations.

• What causes ControlNet packet loss?

  Packet loss is often due to loose BNC connectors or poor cable termination. Ensure that all ControlNet taps are secure and that the network is properly terminated with 75-ohm resistors at both extremities.

• Can the NAP port be used for permanent control?

  The Network Access Port (NAP) is for diagnostic and temporary programming tasks only. It is not designed for permanent connectivity or high-speed control loops. Improper use may cause communication frame errors.