Overview
The Allen-Bradley 1756-L55 ControlLogix 5555 processor is a core control component within Rockwell Automation’s modular 1756 ControlLogix platform. Designed for applications requiring reliable CPU performance within modular automation systems, this module provides essential controller functionality and supports multiple communication options through the ControlLogix backplane. The 1756-L55 is commonly deployed in medium to large industrial automation environments where dependable system control is required.
Key Features
- 100 MHz processor supporting up to 128 discrete and 128 analog I/O points
- Compatible with external memory modules for flexible data handling
- Supports Ethernet, ControlNet, and DeviceNet networks; includes RS-232 serial port for ASCII, DF1, DH-485, and Modbus communication
- Ships with included 1756-BA1 backup battery for maintaining critical memory functions
- Built to withstand industrial environmental conditions as defined by applicable IEC standards
Technical Specifications
- Processor: 100 MHz
- Memory: No internal user memory
- Maximum I/O: 128 discrete and 128 analog I/O points
- Operating Temperature: 0 to 60 degrees Celsius (32 to 140 degrees Fahrenheit)
- Storage Temperature: -40 to 85 degrees Celsius (-40 to 185 degrees Fahrenheit)
- Power Consumption: 1.23–1.25 A at 5.1 VDC (backplane); 0.014 A at 24 VDC; power dissipation 5.6–5.7 W
- Weight: Approximately 0.35 kilograms (12.5 ounces)
- Isolation Voltage: 30 V continuous
Typical Applications
- Manufacturing and machine control systems requiring centralized ControlLogix processing
- Process automation with distributed I/O networks (EtherNet/IP, ControlNet, DeviceNet)
- Energy and infrastructure automation requiring robust, scalable control
- Multi-network industrial environments requiring Ethernet and legacy serial communication
Compatibility & Replacements
Compatible With
- 1756 ControlLogix chassis (all standard configurations)
- Memory expansion modules: 1756-M12, 1756-M13, 1756-M14, 1756-M16, 1756-M22, 1756-M23, 1756-M24
- ControlLogix digital and analog I/O modules (1756-series)
- Communication adapters: 1756-CN2, 1756-DNB, 1756-ENBT, 1756-EWEB
- Studio 5000 Logix Designer programming environment
Replaces / Drop-In Replacement For
- Earlier ControlLogix processors in systems requiring 100 MHz processing power and basic I/O scalability
- Legacy 1756-L5x series units in compatible 1756 chassis configurations
- Verify compatibility with your system integrator before ordering.
Works With
- Studio 5000 Logix Designer (RSLogix 5000 family)
- EtherNet/IP networks and protocols
- ControlNet and DeviceNet industrial networks
- DH+ and DH-485 legacy serial networks
- Remote I/O and distributed I/O systems
