Allen-Bradley 1768-L45 CompactLogix Processor 3MB

1768-L45 Allen-Bradley CompactLogix Processor Module

Product Introduction

The 1768-L45 processor module comes from the Allen-Bradley CompactLogix product family. It handles medium-sized control applications with robust Logix platform capabilities. System integrators choose this controller for its 3MB integrated memory and extensive I/O support.

This controller requires a power supply, an end cap, a programming cable, and mounting hardware or a DIN rail for proper installation. The 1768-L45 works seamlessly with 1769 Compact I/O modules and 1768 backplane modules.

With 3MB of built-in memory, this processor manages complex control logic, data logging, and communication tasks efficiently. Furthermore, the 1768-L45 supports optional CompactFlash memory for program backup and data transfer between controllers.

Technical Specifications

The 1768-L45 offers impressive specifications for demanding industrial environments.

Key parameters include:

• Manufacturer: Allen-Bradley

• Part Number: 1768-L45

• Product Line: CompactLogix

• Module Type: Processor Module

• Integrated Memory: 3 MB

• Communication Ports: One (1) RS232 (isolated)

• Maximum I/O Modules Supported: 30 modules (1769 series)

• Maximum I/O Banks Supported: 3 banks

• Maximum 1768 Modules Supported: 4 modules

• Backplane Current: 2.0 Amps at 24 Volts

• Power Consumption: 48.0 Watts maximum

• Power Dissipation: 8.3 Watts

• Isolation Voltage: 30 Volts Continuous (tested at 500V AC for 60s)

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

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

• Relative Humidity: 5% to 95% non-condensing

• Vibration Resistance: 5G at 10–500 Hz, 0.030 in. peak-to-peak

• Operating Shock: 30G

• Non-Operating Shock: 50G

• Enclosure Rating: Open type

• Temperature Code: T4 (135°C)

Memory and Data Management

The 1768-L45 includes 3MB of integrated memory. This capacity stores user programs, tag data, configuration settings, and communication buffers.

Moreover, this controller supports an optional 1784-CF128 CompactFlash memory card. This non-volatile storage enables automatic program loading, modular data transfer to another compatible controller, and protection against accidental program deletion.

With this memory flexibility, you can back up critical control logic and restore it quickly during system maintenance. The 1768-L45 also supports tag-based and alias addressing, simplifying programming and improving code readability.

Communication and Connectivity

The 1768-L45 includes a fully isolated RS232 serial port. This port supports communication speeds up to 38.4 Kbps and operates with DF1 Full Duplex, DF1 Half Duplex, and DH485 protocols.

For programming and connectivity, Allen-Bradley recommends using either the 1747-CP3 or 1756-CP3 serial cables. These cables feature a right-angle connector on the controller side and a straight connector for the serial port. The cable length measures 3 meters, providing flexible placement options.

For Ethernet and other communication protocols, the 1768-L45 supports up to two communication modules. Specifically, you can install the 1768-ENBT Ethernet module or the 1768-EWEB web server module. This flexibility allows integration with various network architectures.

I/O Expansion Capabilities

The 1768-L45 supports up to 30 1769 Compact I/O modules distributed across three expansion banks. This capacity handles extensive digital and analog input/output requirements for medium to large control systems.

Additionally, the controller supports up to four 1768 backplane modules. These modules can include communication adapters, additional memory, or specialized function modules.

When planning your system layout, consider the backplane current requirements. The 1768-L45 draws 2.0 Amps at 24 Volts for the controller itself. With 1769 modules, the backplane current draw reaches 2.0 Amps at 5.7 Volts. For 1768 modules, the draw is 5.6 Amps at 5 Volts. The total backplane current with both module types reaches 7.6 Amps at 5.2 Volts.

Mechanical and Mounting Information

The 1768-L45 measures 5.18 x 2.65 x 4.80 inches (HxWxD) and weighs approximately 11.9 ounces (0.34 kg). Its compact design fits easily into control cabinets with limited space.

Mounting options include panel mounting or DIN rail installation. For panel mounting, use M4 or #8 screws. Ensure the mounting surface is flat and secure to prevent vibration-related issues.

Maintain proper clearances around the 1768-L45 for ventilation. Allow top and bottom clearances of 105 mm (4.13 inches) and side clearances of 90 mm (3.54 inches). These clearances ensure adequate air circulation and keep the operating temperature within the 0° to 60°C range.

Environmental and Certifications

The 1768-L45 carries a T4 temperature code (135°C) and works with any open-style enclosure. This rating makes the controller suitable for various industrial environments.

This module meets CISPR 11 Group 1, Class A emission standards for industrial settings. It also holds cUL-us certification, confirming compliance with US and Canadian safety requirements.

The controller withstands 5G vibration at 10–500 Hz and 30G operating shock. Non-operating shock tolerance reaches 50G, providing durability during transport and installation.

Packaging and Shipping

Each 1768-L45 ships in protective packaging to ensure safe delivery. The package includes the processor module only.

We do not include power supplies, cables, mounting hardware, CompactFlash cards, or programming software. These accessories must be ordered separately based on your system requirements.

We ship all orders via FedEx, UPS, or DHL. Choose your preferred carrier at checkout. Delivery times vary by destination, but most orders arrive within 3–7 business days.

Frequently Asked Questions

1. What is the memory capacity of the 1768-L45?
The 1768-L45 includes 3MB of integrated memory for user programs and data.

2. How many I/O modules does the 1768-L45 support?
This controller supports up to 30 1769 Compact I/O modules across three expansion banks.

3. What programming cables work with the 1768-L45?
You can use either the 1747-CP3 or 1756-CP3 serial cable for programming and connectivity.

4. Can I add Ethernet communication to the 1768-L45?
Yes, the 1768-L45 supports up to two communication modules, including the 1768-ENBT Ethernet module.

5. What is the operating temperature range for the 1768-L45?
The 1768-L45 operates from 0° to +60°C (+32° to +140°F) with 5% to 95% non-condensing humidity.