1756-L55M13 ControlLogix 5555 Controller Technical Guide
Product Introduction
The Allen-Bradley 1756-L55M13 belongs to the ControlLogix 5555 controller family from Rockwell Automation. This processor module provides 1.5 MB of user memory for logic and data storage. It also includes a dedicated 208 KB memory buffer for I/O handling. The 1756-L55M13 supports up to 128,000 digital I/O points and 4,000 analog inputs. Its typical program scan time reaches 0.08 ms, ensuring fast response for critical processes. The controller mounts into any slot of a 1756 ControlLogix chassis. It draws 1.23 A from the 5 V DC backplane and 14 mA from the 24 V DC supply. An integrated RS-232 serial port enables programming and local diagnostics. Users program the 1756-L55M13 using RSLogix 5000 software and update firmware via ControlFlash. This controller also supports multiple network protocols, including ControlNet, EtherNet/IP, and DeviceNet.
Core Value
The 1756-L55M13 delivers significant value for maintaining legacy ControlLogix systems. Firstly, its 1.5 MB memory capacity accommodates complex control programs without frequent optimization. Moreover, the controller supports redundant system configurations for critical applications that require high availability. The 1756-L55M13 provides deterministic 0.08 ms scan times that ensure consistent machine control. Additionally, its compatibility with standard 1756 chassis simplifies integration into existing installations. The processor supports online editing, allowing engineers to modify logic without stopping production. This feature minimizes downtime during program updates. Furthermore, the 1756-L55M13 offers flexible communication options through add-on modules. Its robust design operates reliably in 0°C to 60°C environments with 5% to 95% humidity. These characteristics make the 1756-L55M13 a dependable choice for plant-floor automation.
Technical Insights
The 1756-L55M13 operates as a Series A controller without onboard nonvolatile memory. It requires a 1756-BA1 battery or 1756-BATM battery module for memory retention during power loss. The 1756-BA1 battery provides approximately 63 days of backup at 25°C, while the 1756-BATM extends this to 299 days. Engineers must use compatible memory boards for specific configurations. For instance, the 1756-L55M13 supports firmware revisions from 10.xx to 13.xx. Users should verify firmware compatibility before performing upgrades. The controller uses a 1756-CNB or 1756-ENBT module to connect with plant networks. Specifically, the 1756-L55M13 handles up to 15 connections for messaging and data exchange. Its embedded RS-232 port supports DF1 protocol for point-to-point communication. This port also allows firmware flashing using a serial cable. Engineers often pair the 1756-L55M13 with 1756-I/O modules for distributed control. The controller's memory organization separates logic data, tag values, and I/O images. This structure simplifies debugging and improves scan efficiency. Users can configure the 1756-L55M13 for time synchronization across multiple controllers using CIP Sync.
Installation and Maintenance
Proper installation of the 1756-L55M13 ensures reliable operation in industrial settings. Firstly, insert the processor into any empty slot of the 1756-A4, A7, A10, or A13 chassis. Push the module firmly until the locking mechanism clicks into place. Ensure that the chassis backplane supplies adequate power for all installed modules. The 1756-L55M13 requires a 1.23 A current from the 5 V supply. Check the total chassis load to avoid overloading the power supply. Install the 1756-BA1 battery into the designated compartment on the processor faceplate. Then, connect the programming cable to the RS-232 port for initial configuration. Use RSLogix 5000 to set the controller's name, IP address, and communication parameters. For maintenance, regularly inspect the battery status LED on the front panel. Replace the battery when the LED flashes red or at scheduled intervals. The 1756-L55M13 also includes a status display that shows fault codes. Refer to the manual to interpret these codes accurately. Keep the controller firmware updated to address potential security vulnerabilities. Clean the module faceplate with dry compressed air to prevent dust accumulation. Moreover, verify that environmental conditions remain within the specified operating ranges. Store spare 1756-L55M13 units in anti-static packaging to avoid electrostatic damage.
Buyer's Guide FAQ
What is the memory capacity of the Allen-Bradley 1756-L55M13 processor?
The 1756-L55M13 provides 1.5 MB of user memory and 208 KB of dedicated I/O memory. This capacity suits medium to large control applications with extensive logic and data tables.
Does the 1756-L55M13 support redundant controller configurations?
Yes, the 1756-L55M13 supports redundant systems when paired with a 1756-RM redundancy module. This configuration provides high availability for critical processes.
What battery does the 1756-L55M13 require for program retention?
The 1756-L55M13 uses either a 1756-BA1 battery or a 1756-BATM battery module. Both options retain the program and tag data during power outages.
Can I use the 1756-L55M13 with EtherNet/IP networks?
Yes, the 1756-L55M13 connects to EtherNet/IP networks through a 1756-ENBT or 1756-EN2T communication module. This setup enables seamless integration with other Rockwell devices.
What software do I need to program the 1756-L55M13?
You must use RSLogix 5000 software version 10.xx to 13.xx to program the 1756-L55M13. Later software versions may not support this legacy controller.
