Allen Bradley 1756-L74 ControlLogix Programmable Automation Controller

The Allen Bradley 1756-L74 is a high-performance ControlLogix programmable automation controller (PAC) designed for large-scale industrial automation applications. With 16MB of user memory, it provides high-speed processing, advanced motion control, and real-time system monitoring, making it ideal for complex automation environments. It integrates seamlessly into Rockwell Automation’s Integrated Architecture system, offering EtherNet/IP, ControlNet, and DeviceNet communication capabilities.

Technical Specifications

• Manufacturer: Allen Bradley (Rockwell Automation)
• Model: 1756-L74
• Controller Type: ControlLogix Programmable Automation Controller (PAC)
• User Memory: 16MB
• I/O Capacity: Supports local and remote I/O via EtherNet/IP, ControlNet, and DeviceNet
• Communication Options:
  • EtherNet/IP
  • ControlNet
  • DeviceNet
  • Serial (RS-232)
  • Third-party networks via communication modules
• Chassis Compatibility: 1756 ControlLogix chassis (any slot)
• Backplane Current Draw:
  • 1.1 A at 5.1V DC
  • 0.047 A at 24V DC
• Battery: Energy storage module (non-removable)
• Firmware Compatibility: Requires specific firmware version matching system requirements
• Operating Temperature: 0°C to 60°C (32°F to 140°F)

Key Features

• 16MB user memory for handling large-scale automation applications
• Fast execution speed for real-time industrial control and motion applications
• Supports multiple network protocols for flexible system integration
• Modular design allows easy expansion with I/O and communication modules
• Seamless integration with Rockwell Automation’s Logix platform
• Advanced diagnostics and troubleshooting capabilities via FactoryTalk software

Compatible Allen Bradley Components

• 1756 I/O Modules (Digital, Analog, Specialty I/O)
• Allen Bradley PowerFlex Variable Frequency Drives (VFDs)
• FactoryTalk View SE/ME for HMI visualization and diagnostics
• RSLogix 5000 / Studio 5000 Logix Designer for programming
• ControlNet, DeviceNet, and EtherNet/IP communication adapters

Industry Applications

• Manufacturing and process automation
• Material handling and robotics
• Oil, gas, and petrochemical process control
• Food and beverage production lines
• Water and wastewater treatment facilities
• Energy and power generation automation

Installation & Operational Notes

• Requires installation in a 1756 ControlLogix chassis
• Ensure firmware compatibility with the automation system before upgrading
• Use Studio 5000 Logix Designer for programming and system configuration
• Supports remote monitoring and troubleshooting via FactoryTalk and EtherNet/IP
• Regular firmware updates recommended for optimal performance and security

The Allen Bradley 1756-L74 is a Programmable Automation Controller (PAC) that is used for implementing factory and process automation requirements. This controller has a modern design that is specifically catered to meet the requirements of today’s industrial automation requirements.

The 1756-L74 is a single slot width controller, designed with a compact and assembly. It is a chassis-based device that is powered internally by the backplane power distributed to the chassis’ electronic circuitry. This controller is compatible for installation in all of the available chassis made for the ControlLogix system such as 1756-A4, 1756-A4K, 1756-A7, 1756-A7K, 1756-A10, 1756-A10K, 1756-A13, 1756-A13K,1756-A17, 1756-A17 K.

The 1756-L74 is an environment-friendly controller, as it utilizes energy storage module instead of batteries for keeping the contents of the Random Access Memory (RAM). Energy storage modules are capacitor based which means RAM memory is retained by the energy stored within the capacitors. These energy storage modules are removable and replaceable. For this controller, a 1756-ESMCAP is pre-installed while other compatible modules include 1756-ESMNSE, 1756-ESMNSEK, 1756-ESMNRM, and 1756-ESMNRMK.

Features

The 1756-L74 comes with a 16MB user memory, 0.98 MB I/O memory and ships with a 1GB non-volatile memory via the 1784-SD1. The non-volatile memory may be expanded up to 2GB by replacing the existing unit the 1784-SD2, 2 GB Secure Digital (SD) card.

The 1756-L74 communicates via the built-in USB communication port, however, this port is not ideal for industrial communication. For the mentioned purpose, user may install additional communication adapters that supports specific communication protocols such as EtherNet/IP, ControlNet, DeviceNet, Data Highway Plus, Remote I/O, SynchLink and Third-party process and device networks.

It is also compatible communicating through EtherNet/IP, ControlNet, DeviceNet, Data Highway Plus, Remote I/O, and SynchLink. Its integrated motion features are SERCOS interface, analog options, and integrated motion on the EtherNet/IP network. The programming languages are relay ladder, structured text, function diagram, and sequential function chart.

The 1756-L74 controller has a 16 MB user memory and a 0.98 MB I/O memory. It has 128,000 total and digital I/O and 4000 analog I/O. The controller has compatible energy storage modules like the 1756-ESMCAP, 1756-ESMCAPK, 1756-ESMNSE, 1756-ESMNSEK, 1756-ESMNRM, and the 1756-ESMNRMK modules. The 1756-L74 controller only requires 2.5 W of power dissipation and only 8.5 BTU/hr of thermal dissipation. It has a USB port-to-system basic insulation type. It has a chassis-based module location at any slot for the 1756 series with a 1-slot width. Possible chassis include the 1756-A4, 1756-A4K, 1756-A7, 1756-A7K, 1756-A10, 1756-A10K, 1756-A13, 1756-A13K,1756-A17, and the 1756-A17 K. The 1756-L74 uses a standard power supply such as the 1756-PA50, 1756-PA72, and the 1756-PA72K. For power supply redundancy, it only uses the 1756-PA75R, 1756-PA75RK, 1756-PB75R, 1756-PB75RK, 1756-PSCA2, or the 1756-PSCA2K. The 1756-L74 has an open-style enclosure, an operating temperature of 0-60°C, and a non-operating temperature of -40 – 85°C. Its operating vibration is 10g at 500 Hz at 2 g, its operating shock is 30 g, and its non-operating shock is 50 g.

Specifications