ControlLogix 5570 2MB PAC Module | 1756-L71/B | Allen Bradley

Allen Bradley 1756-L71 Series B ControlLogix 2MB Processor Module

Product Overview

The 1756-L71 (Part Number: 1756-L71/B) is a high-performance Programmable Automation Controller (PAC) from the Allen-Bradley ControlLogix 5570 series. Specifically engineered for medium-to-large scale industrial automation, this Series B hardware revision delivers significant processing speed improvements over legacy L6 controllers. With 2 MB of user memory, the 1756-L71/B is optimized for high-speed discrete control, motion synchronization, and integrated plant-wide communications.

Unlike earlier generations, the 5570 series features a built-in USB 2.0 port for rapid programming and diagnostics, alongside a dedicated 4-character alphanumeric display for real-time status monitoring. The 1756-L71/B (1756-L71/B) does not require a battery for program retention, as it utilizes an internal Energy Storage Module (ESM) to write data to nonvolatile memory during power-down cycles, significantly reducing maintenance requirements.

Detailed Technical Specifications

The 1756-L71/B offers precision control with the following technical parameters:

• Manufacturer: Allen-Bradley (Rockwell Automation)

• Model / Part Number: 1756-L71/B

• Series: ControlLogix 5570 (Logix5571)

• User Memory: 2 MB

• I/O Memory: 0.98 MB (Enhanced from legacy models)

• Nonvolatile Memory: Secure Digital (SD) Card support (1784-SD1 ships standard; 1784-SD2 optional)

• Communication Ports: 1 USB 2.0 (Full Speed) for programming and configuration

• Maximum Digital I/O: 128,000 points

• Maximum Analog I/O: 4,000 points

• Logic Execution Time: 0.08 ms per 1,000 instructions

• Backplane Current (5.1V DC): 800 mA

• Backplane Current (24V DC): 5 mA

• Power Dissipation: 2.5 Watts

• Status Indicators: 4-character alphanumeric display; RUN, FORCE, I/O, OK LED indicators

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

• Dimensions: 2.5 cm x 14.7 cm x 14.2 cm (1.0 in x 5.8 in x 5.6 in)

• Shipping Weight: 0.4 kg (0.9 lbs)