Allen-Bradley 1756-L55M13 Controller Processor

The Allen-Bradley 1756-L55M13 serves as a central processing unit within the ControlLogix 5555 family. This controller offers a substantial 1.5 MB user memory for logic and data storage. Additionally, it reserves 208 KB of dedicated memory specifically for I/O tasks. While this module provides high-speed execution, it does not include onboard nonvolatile memory. Consequently, users should maintain external backups or use a battery to preserve volatile data. The 1756-BA1 lithium battery provides the necessary power to retain memory during shutdowns.

Connectivity and Industrial Networking

This processor demonstrates exceptional versatility through its extensive communication support. It integrates easily with Data Highway Plus, ControlNet, and DeviceNet architectures. Furthermore, the unit manages Ethernet/IP, SynchLink, and DH-485 protocols for broad system compatibility. This wide range of options allows the controller to bridge various factory floor networks. It also supports Modbus connectivity via specialized ladder routines. For programming, engineers typically utilize the 1756-CP3 or 1747-CP3 serial cables.

Environmental and Electrical Specifications

• Backplane Current (5.1V DC): 1.23 Amps
• Backplane Current (24V DC): 0.014 Amps
• Power Dissipation: 5.6 Watts
• Thermal Dissipation: 19.1 BTU per hour
• Operational Temperature: 0 to 60°C (32 to 140°F)
• Vibration Resistance: 2 g @ 10 to 500 Hz
• Operating Shock: 30 g
• Isolation Voltage: 30V Continuous

Physical Design and Redundancy

The 1756-L55M13 features an open-style construction for installation in protected industrial enclosures. This lightweight module weighs approximately 0.35 kg and occupies a single chassis slot. Beyond standalone operation, this processor supports high-availability applications through redundancy. Engineers can pair two identical controllers within a single ControlNet network for fail-safe performance. This setup ensures continuous operation for critical industrial processes that cannot tolerate downtime.