Allen-Bradley 1756-L55M12 ControlLogix Processor 750KB

1756-L55M12 Logix5555 Controller for ControlLogix

Product Introduction

The 1756-L55M12 from Allen-Bradley stands as a capable processor module within the renowned ControlLogix family. Engineers choose this controller when they need to manage complex automation systems with both efficiency and unwavering reliability.

To begin with, this module offers substantial memory resources for demanding applications. Specifically, it provides 750 KB of user memory for logic and data storage, alongside 208 KB of dedicated I/O memory. In addition, its maximum I/O capacity reaches an impressive 128,000 digital points. For analog signals, it supports 4,000 inputs and 2,000 outputs. Consequently, this scalability makes it a versatile foundation for a wide range of industrial control projects.

Processing Speed and Communication Flexibility

Beyond its memory capacity, the 1756-L55M12 delivers remarkable processing performance. For instance, its program scan time is merely 0.08 milliseconds, which ensures extremely rapid execution of control logic. Therefore, this speed proves particularly valuable for time-sensitive processes and high-speed production lines.

Furthermore, this controller supports a broad selection of communication networks. Notably, it works seamlessly with ControlNet, EtherNet/IP, DH+, DeviceNet, and universal remote I/O networks. As a result, system integrators can easily connect it to existing plant-floor infrastructures. For programming and serial connectivity, users typically employ either the 1756-CP3 or 1747-CP3 serial cables.

Power Ratings and Environmental Durability

Understanding the power specifications helps ensure a successful installation. For example, the 1756-L55M12 draws 1.23 A at 5.1V DC and 14 mA at 24V DC from the chassis backplane. Meanwhile, its power dissipation measures 5.6 W, while thermal dissipation reaches 19.1 BTU/hr. These figures allow for accurate heat load calculations within the control cabinet.

Moreover, this processor module operates reliably under demanding environmental conditions. Its operating temperature spans from 0 °C to 60 °C (32 °F to 140 °F). For storage, it withstands extreme temperatures between -40 °C and 85 °C (-40 °F to 185 °F). Likewise, the relative humidity tolerance ranges from 5% to 95%, non-condensing. Additionally, it features an operating shock rating of 30 g and a non-operating shock rating of 50 g. Its vibration resistance is specified at 2 g across a frequency range of 10 to 500 Hz.

Installation Guidance and Redundancy Support

Proper physical placement guarantees optimal performance from the 1756-L55M12. This single-slot module fits into any standard ControlLogix chassis without special mounting requirements. Furthermore, it weighs just 0.78 pounds (0.35 kilograms), which makes handling and installation straightforward.

Significantly, this controller supports redundant system configurations for enhanced availability. However, when deploying redundancy, the modules must operate within a ControlNet network. This requirement ensures proper synchronization and failover behavior. For memory backup, a 1756-BA1 or 1756-BATM lithium battery maintains the real-time clock and retained data. The battery itself weighs 0.59 g, and users should order replacements only when the low-battery indicator appears.

Additionally, the 1756-L55M12 features an open-style enclosure with basic insulation. Its isolation voltage is rated at 30V continuous, and it has passed dielectric testing at 707V DC for 60 seconds. Finally, the conducted RF immunity meets the 10V rms standard with 1 kHz sine-wave 80% AM from 150 kHz to 80 MHz.

Packaging and Shipping Information

Each shipment of the 1756-L55M12 includes the processor module itself. For clarity, the battery and serial cables are not included and must be ordered separately based on your specific needs.

We dispatch all orders using trusted global carriers, including Fedex, UPS, and DHL. The module follows the standard ControlLogix form factor and requires one chassis slot for installation.

Frequently Asked Questions (FAQ)

1. What is the maximum I/O capacity of the 1756-L55M12?
The 1756-L55M12 supports up to 128,000 digital I/O points. For analog signals, it handles 4,000 inputs and 2,000 outputs simultaneously.

2. Can the 1756-L55M12 be used in a redundant system?
Yes, the 1756-L55M12 can participate in a redundant controller configuration. However, you must deploy it on a ControlNet network for redundancy to function correctly.

3. What battery does the 1756-L55M12 require?
This processor uses either the 1756-BA1 or 1756-BATM lithium battery. These batteries provide backup power for the real-time clock and retained memory during power outages.

4. What communication protocols does this processor support?
The 1756-L55M12 supports ControlNet, EtherNet/IP, DH+, DeviceNet, and universal remote I/O. Therefore, it offers excellent compatibility with diverse industrial networks.

5. How fast is the program scan time for the 1756-L55M12?
The typical program scan time is 0.08 milliseconds. Consequently, this speed makes the controller suitable for high-performance logic execution and time-critical applications.