Logix5572S PAC Controller | Allen-Bradley 1756-L72S

Product Overview

The Allen-Bradley 1756-L72S is a high-performance GuardLogix 5570 Programmable Automation Controller (PAC) engineered by Rockwell Automation. This dual-processor module integrates standard and safety control functions within a single project file, maximizing processing capabilities for motion and complex logic applications. Featuring 4 MB of standard user memory and 2 MB of dedicated safety memory, it serves as the primary controller alongside a required 1756-L7SP (or 1756-L7SPK) safety partner module to achieve stringent SIL 3, PLe, and Cat. 4 safety ratings. Weighing only 0.55 lbs (0.25 kg), this batteryless processor utilizes modern energy storage modules (ESM) to maintain volatile memory security without maintenance downtime.

Key Advantages

• Unified Control Architecture: Combines standard machine control and functional safety systems into one unified hardware slot and application software project.
• Battery-Free Operation: Equipped with an integrated 1756-ESMCAP energy storage capacitor, eliminating the environmental impact and replacement schedules associated with traditional lithium batteries.
• Massive I/O Scalability: Supports up to 128,000 digital I/O points and up to 4,000 analog I/O points across local backplanes or distributed industrial networks.
• Lightweight Slot Integration: Weighing just 0.55 lbs, the open-style enclosure installs effortlessly into any slot of a ControlLogix 1756 chassis, allowing multiple processors to co-exist in the same frame.
• Robust Non-Volatile Memory: Ships with a pre-installed 1 GB 1784-SD1 Secure Digital card, ensuring secure firmware back-up and boot loading, expandable up to 2 GB via 1784-SD2.

Technical Specifications

Quick Installation Tips

• Slot Layout Planning: The 1756-L72S is an open-style module that can be inserted into any standard slot of a 1756 ControlLogix chassis. However, it must be paired in a neighboring slot with its safety partner, the 1756-L7SP module. Despite their minimal combined weight (each processor is only 0.55 lbs), ensure both modules are locked into the backplane connectors firmly.
• Chassis and Power Compatibility: This processor is fully compatible with standard or conformally coated chassis assemblies (e.g., 1756-A4, 1756-A7, 1756-A10, up to 1756-A17 standard/K-series) and can be powered by standard industrial power supplies like the 1756-PA75 or 1756-PB75 ranges.
• Energy Storage Selection: The unit comes standard with the integrated 1756-ESMCAP capacitor. If your site applications prohibit USB configuration or SD card utilization for enhanced security, consider replacing it with the 1756-ESMNRM module. For systems requiring immediate power cuts without residual clock uptime, select the 1756-ESMNSE option.

Technical FAQs

Q1: Is the safety partner module configured separately from the 1756-L72S primary module?

A1: No. The safety partner controller (1756-L7SP) is automatically configured by the system. Both standard and safety routines are developed and compiled within a single, integrated project environment, drastically cutting engineering time compared to isolated safety solutions.

Q2: What communication capabilities are built onto the front faceplate of the module?

A2: The 1756-L72S features a built-in USB port intended for programming, configuration, firmware updates, and rapid online diagnostics. For real-time plant network communication and safety I/O data links, separate EtherNet/IP, ControlNet, or DeviceNet communication bridge modules must be added to the chassis.

Q3: How many tasks can this processor handle concurrently?

A3: The controller supports a maximum of 31 standard tasks and 1 dedicated safety task, with a high capacity of up to 100 separate logic programs allowed per single task. Event tasks can be triggered by all supported system event types.