Product Overview

The 1756-L65 is a ControlLogix Logix5565 series programmable automation controller manufactured by Rockwell Automation, positioned as a high-memory processor for medium-to-large motion control, process control, and hybrid automation applications. Within the Logix5565 family, the 1756-L65 represents the highest user memory capacity of the L6x generation, offering 32 MB of user memory for program and data storage alongside 478 KB of dedicated I/O memory.

In a ControlLogix chassis, the 1756-L65 serves as the central execution engine, running Logix5000 control tasks and communicating with I/O modules, communication bridges, and peer controllers across the backplane and industrial networks. The controller supports sequential, process, motion, and drive control within a unified programming environment, with integrated motion capability through EtherNet/IP, SERCOS interface, and analog inputs. Rockwell Automation officially discontinued the 1756-L65 on June 1, 2017, with no direct same-series replacement, making remaining inventory from surplus and refurbished channels the sole source for facilities maintaining L6x-based systems.

 

Technical Specifications

Parameter Name	Parameter Value
Product Model	1756-L65
Manufacturer	Rockwell Automation / Allen-Bradley
Product Type	ControlLogix Logix5565 Programmable Controller
User Memory	32 MB
I/O Memory	478 KB
Maximum Total I/O	128,000 points
Maximum Analog I/O	4,000 channels
Maximum Digital I/O	128,000 points
Backplane Current (5.1V DC)	1,200 mA
Backplane Current (24V DC)	14 mA
Power Dissipation	3.5 W
Thermal Dissipation	11.9 BTU/hr
Serial Port	1 × RS-232
CompactFlash Support	128 MB (1756-CF128)
Battery	1756-BA2 lithium
Controller Tasks	32 tasks; 100 programs per task
Maximum Connections	250
Operating Temperature	0…60 °C
Isolation Voltage	30V continuous
Slot Width	1

 

Main Features and Advantages

Highest memory capacity in the Logix5565 generation: The 1756-L65 provides 32 MB of user memory, the maximum available in the L6x controller series, enabling storage of large programs, extensive tag databases, and recipe or data-logging applications that would exceed the capacity of lower-memory models such as the 1756-L61 or 1756-L62. For applications involving complex motion profiles, extensive process control logic, or historical data buffering, the 1756-L65 eliminates the memory constraints that often drive premature controller upgrades.

Integrated multi-discipline control platform: The 1756-L65 consolidates sequential control, process control, motion control, and drive control into a single unified platform programmed with RSLogix 5000. Motion control functionality is embedded directly into the controller and programming software, while process control capabilities include user-defined function blocks and integrated drive configuration. This consolidation allows machine builders and system integrators to use one controller for mixed applications—such as a packaging line that combines servo motion, PID temperature loops, and discrete sequencing—without separate controllers for each discipline.

Flexible communication and networking: The 1756-L65 supports the full ControlLogix communication module portfolio, including EtherNet/IP, ControlNet, DeviceNet, Remote I/O, Data Highway Plus, and SynchLink, plus third-party process and device networks. The built-in RS-232 serial port supports ASCII, DF1 full/half-duplex, DF1 radio modem, DH-485, and Modbus via logic. This breadth of connectivity allows the 1756-L65 to integrate into both modern Ethernet-based architectures and legacy networks within the same control system.