Allen-Bradley 1756-L55 ControlLogix 5555 Controller

Allen-Bradley 1756-L55 ControlLogix 5555 Controller

Price range: $240.87 through $1,425.69

The Allen-Bradley 1756-L55 is a ControlLogix 5555 programmable logic controller designed for industrial automation programming. It requires a plug-in memory expansion card (such as the 1756-M12, M13, M14, M15, or M22) to establish user memory capacity for discrete, process, and motion control routines. An onboard RS-232 serial port enables direct local communication with programming terminals, operator interfaces, and peripheral field devices. Supporting Removal and Insertion Under Power (RIUP), it provides continuous operational flexibility across standard ControlLogix chassis architectures.

$240.87
$976.50
$1,425.69
SKU: 1756-L55 Category: Brand:

Description

  • Part Number: 1756-L55
  • Manufacturer: Allen-Bradley
  • Type: ControlLogix 5555 Controller
  • Series: ControlLogix 1756 Series
  • Application: Industrial Process Automation & Control
  • Size // Rating: Requires M1x/M2x Memory Expansion Card
  • Connection Type: RS-232 Serial Port / Backplane
  • Compatibility: Allen-Bradley ControlLogix 1756 System

TCI is not an authorized Allen-Bradley distributor.

Documentation

No documentation is available for this product.

Warranty Coverage

This product is backed by a TCI Supply 1 year Warranty.

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Description

The Allen-Bradley 1756-L55 is a core 5555 Series ControlLogix processor designed for reliable control across discrete, process, and motion control applications. Unlike processors with fixed onboard user memory, the base 1756-L55 module relies entirely on modular memory daughtercards—such as the 1756-M12 (750 KB), 1756-M13 (1.5 MB), 1756-M14 (3.5 MB), 1756-M15 (7.5 MB), or non-volatile 1756-M22 series—to define its available RAM and non-volatile storage capacities.

To facilitate local field configuration and communication, the 1756-L55 includes a front-panel 9-pin RS-232 serial communication port. This port supports DF1 full-duplex/half-duplex, DH-485, and ASCII protocols, enabling direct links to programming PCs, operator interface terminals (HMIs), bar code scanners, and external devices. Programmed using RSLogix 5000 software (firmware revisions 8 through 16), the controller integrates seamlessly into multi-chassis networks via EtherNet/IP, ControlNet, and DeviceNet bridge modules.

User memory retention during plant power outages is maintained by a replaceable external lithium battery (such as the 1756-BA1 or 1756-BATM battery assembly). Diagnostic LEDs on the front panel provide real-time status indication for run mode, controller health, serial port traffic, and battery status. With full support for Removal and Insertion Under Power (RIUP), maintenance personnel can remove or replace the 1756-L55 module live without removing power from the ControlLogix chassis backplane.

Frequently Asked Questions

What is the primary function of the Allen-Bradley 1756-L55 controller?

What is the primary function of the Allen-Bradley 1756-L55 controller?

Why does the 1756-L55 require a memory expansion card?

The base 1756-L55 processor does not have built-in user RAM; it requires a plug-in memory module (such as the 1756-M12, M13, M14, M15, or M22) to define the user memory capacity for ladder logic and tag data.

Which memory expansion cards are compatible with the 1756-L55?

Compatible expansion modules include volatile RAM cards (1756-M12 [750 KB], 1756-M13 [1.5 MB], 1756-M14 [3.5 MB], 1756-M15 [7.5 MB]) and non-volatile memory cards (1756-M22 [750 KB], 1756-M23 [1.5 MB], 1756-M24 [3.5 MB]).

What communication ports are built into the 1756-L55?

It features an onboard RS-232 serial port supporting DF1, DH-485, and ASCII protocols for programming, operator interfaces, and serial device connections.

Which software is required to program the 1756-L55?

The 1756-L55 is configured and programmed using RSLogix 5000 software (supporting firmware versions 8 through 16).

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