Allen-Bradley 1756-L55M13 ControlLogix 5555 Processor Module 1.5MB

Technical Overview

The 1756-L55M13 is a high-performance central processing unit within the ControlLogix 5555 controller family. Engineered for complex industrial automation tasks, this module provides robust control for large-scale applications requiring high-speed logic execution and significant I/O capacity. It features a 1.5 MB user memory and a dedicated 208 KB I/O memory buffer, ensuring efficient data handling and minimized scan times for critical process control.

Designed for chassis-based mounting, the 1756-L55M13 communicates across the 1756 backplane and includes an integrated RS-232 serial port for local programming, diagnostics, and interfacing with older peripheral devices. While the series has been succeeded by newer Logix controllers, it remains a cornerstone for maintaining and supporting legacy ControlLogix architectures.

Product Specifications

• Manufacturer: Allen-Bradley / Rockwell Automation

• Controller Series: ControlLogix 5555

• Part Number: 1756-L55M13

• User Memory: 1.5 MB

• I/O Memory: 208 KB

• Maximum Digital I/O: 128,000 signals

• Maximum Analog I/O: 4,000 inputs / 2,000 outputs

• Logic Scan Time: 0.08 ms typical

• Integrated Communication: One (1) RS-232 Serial Port

• Backplane Current (5V DC): 1.23 Amps

• Backplane Current (24V DC): 14 mA

• Battery Support: Compatible with 1756-BA1 or 1756-BATM

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

• Vibration Resistance: 2 G at 10 to 500 Hz

• Approximate Weight: 0.37 kg (0.81 lbs)

Application and Maintenance

The 1756-L55M13 is typically deployed in discrete manufacturing, motion control, and batch processing where high-density I/O and reliable performance are required. Users should note that this specific model was officially discontinued by the manufacturer on March 31, 2011, making it a critical item for spare-parts inventory to prevent extended downtime in existing facilities. Proper maintenance involves regular battery testing and firmware management via RSLogix 5000 software to ensure system stability.

Frequently Asked Questions

Is the 1756-L55M13 compatible with modern ControlLogix 1756-A7 or A10 chassis?Yes, the module is compatible with standard 1756 ControlLogix chassis. However, ensure that the power supply installed in the chassis provides sufficient 5V DC current to meet the 1.23A requirement of this processor.

Can I use this module to replace a 5580 series controller?No. The original description contained a conflict; the 1756-L55M13 belongs to the 5555 series. It cannot directly replace a 5580 series controller due to differences in architecture and software requirements.