Overview
The Allen-Bradley 1756-L55 /A is a Series A ControlLogix processor module that delivers essential CPU functionality for medium to large industrial automation environments. This module provides essential controller functionality and supports multiple communication options through the ControlLogix backplane. The 1756-L55 processor module is part of the ControlLogix product family (Series A) by Allen-Bradley/Rockwell Automation. This bare processor (without internal user memory) integrates seamlessly into 1756 chassis-based automation systems and requires a separate memory expansion module for program operation.
Key Features
- 100 MHz processor with support for up to 128 discrete and 128 analog I/O points
- Operates with external memory components and a 1756-BA1 battery for data retention during power loss
- Supports communication options including Ethernet, ControlNet, and DeviceNet networks, plus an RS-232 serial port with ASCII, DF1, DH-485, and Modbus protocols
- 32-bit RISC processor with support for up to 10,000 I/O points in a single chassis
- Standard ControlLogix backplane integration with wide module compatibility
Technical Specifications
- Backplane current: 1.23–1.25 A @ 5.1 VDC, 0.014 A @ 24 VDC
- Power dissipation: 5.6–5.7 W; thermal dissipation: 19.1–19.4 BTU/hour
- Operating temperature: 0–60°C (32–140°F); storage temperature: −40–85°C (−40–185°F)
- Weight: 0.35 kg (12.5 oz)
- Meets IEC 60068 ratings for temperature, humidity, vibration, and shock tolerance
- Uses 1756-CP3 or 1747-CP3 serial cable; T4 IEC temperature code
Typical Applications
The 1756-L55 /A is ideal for manufacturing, process control, packaging, material handling, and infrastructure projects requiring reliable mid-scale industrial control. It is commonly deployed in medium to large industrial automation environments where dependable system control is required. Its modular architecture and communication flexibility support both centralized and distributed I/O configurations.
Compatibility & Replacements
The 1756-L55 /A is a drop-in compatible processor for existing ControlLogix 1756 systems. It is compatible with the 1756 ControlLogix chassis and requires a separate memory module for operation. Common memory expansion modules include the 1756-M12 (750 KB) and 1756-M13 (1.5 MB), which must be purchased separately. This Series A processor integrates with all standard ControlLogix I/O modules, communication adapters, and network interfaces. If upgrading, consider memory-equipped variants like the 1756-L55M12 or L55M13 for integrated memory solutions.
