The 1756-L55M22 ControlLogix 5555 Processor Module from Rockwell Automation is a robust mid-generation PLC CPU designed for industrial automation systems requiring stable logic execution, flexible communication expansion, and reliable long-term operation in ControlLogix architectures.
As part of the widely deployed ControlLogix 5555 series, the L55M22 is especially common in legacy and long-life production environments where system stability, deterministic control, and spare-part availability are more important than cutting-edge processing power. It continues to be a critical component in maintenance-heavy industrial infrastructures.
Technical Specifications
| Parameter | Specification |
|---|---|
| Model | 1756-L55M22 |
| Series | ControlLogix 5555 |
| Processor Type | PLC CPU Module |
| User Memory | 750 KB |
| Non-Volatile Memory | 750 KB |
| I/O Capacity | Up to 128,000 points |
| Analog I/O Capacity | 4,000 inputs / 2,000 outputs |
| Backplane Current (5V DC) | ~1.23 A |
| Backplane Current (24V DC) | ~14 mA |
| Program Scan Time | ~0.08 ms |
| Communication | Via external modules (EtherNet/IP, ControlNet, DeviceNet, DH+) |
| Programming Software | RSLogix 5000 (legacy versions) |
| Battery | 1756-BA1 / 1756-BATM lithium backup |
| Operating Temperature | 0°C to 60°C |
| Storage Temperature | -40°C to 85°C |
| Humidity | 5%–95% non-condensing |
| Dimensions (H × W × D) | 13.3 × 5.1 × 14.5 cm |
| Weight | ~0.57 kg |
The module maintains a standard ControlLogix single-slot footprint, ensuring easy installation into existing chassis systems without mechanical modification.
Recommended Related Models
For system expansion or modernization, the following modules are commonly paired with the 1756-L55M22:
- 1756-L61 / L62 ControlLogix CPUs (modern upgrade path)
- 1756-EN2T / ENBT EtherNet/IP communication modules
- 1756-CNB ControlNet Bridge modules
- 1756-IB16 Digital Input modules
- 1756-OB16E Digital Output modules
Popular Allen-Bradley ControlLogix Models
Within the same ecosystem, engineers frequently work with:
- 1756-L1 / L1M legacy controllers
- 1756-L55 family processors
- 1756-L71 / L72 / L73 modern ControlLogix CPUs
- 1756-EN2T high-speed Ethernet modules
- 1756-DNB DeviceNet communication modules
These modules represent the evolution of ControlLogix from legacy deterministic control toward modern IIoT-ready automation systems.
