Description
Product Overview
The 1756-L71 is a Logix5571 programmable automation controller (PAC) within Rockwell Automation ControlLogix 5570 series, designed for high-performance discrete, process, motion, and safety control applications in modular rack-based industrial systems. It is commonly referred to as 1756-L71-CPU.
Technical Specifications
| Item | Parameter |
|---|---|
| Catalog No | 1756-L71 |
| User Memory | 2 MB |
| I/O Memory | 0.98 MB |
| Non-volatile Storage | 1 GB SD card, upgradeable to 2 GB |
| Local Port | 1 × USB 2.0 full-speed (programming only, not permanent network link) |
| Max Supported Motion Axes | 100 axes (CIP Motion over EtherNet/IP) |
| Max Digital I/O | 128,000 points |
| Max Analog I/O | 4,000 points |
| Power Dissipation | 2.5 W |
| Power Requirement | 5 mA @1.2 VDC, 800 mA @5.1 VDC |
| Backup Retention | Capacitor module 1756-ESMCAP, no lithium battery |
| Task Configuration | Up to 32 tasks; max 100 programs per task |
| Programming Languages | Ladder Diagram, Structured Text, Function Block Diagram, Sequential Function Chart |
| Weight | ~0.37 kg |
| Display | 4-character alphanumeric LED for diagnostics & status |
Key Features
- Modular ControlLogix backplane design, install into 1756 series chassis.
- Supports full controller redundancy for high-availability critical production lines.
- Multi-network capability via separate communication modules: EtherNet/IP, ControlNet, DeviceNet, DH+, Remote I/O, SynchLink.
- Advanced motion control for Kinetix servo drives, supports cam profiling, jerk limiting, kinematic transformations.
- Built-in diagnostics, fault logging and alarm shelving for machine health monitoring.
- Capacitor-based memory backup eliminates battery replacement and battery leakage risk.
- Compatible with Studio5000 / RSLogix 5000 programming software.
Typical Applications
- Assembly lines, packaging machinery, metal forming
- Pulp & paper, water treatment, chemical process control
- Material handling, conveyor systems
- Multi-axis coordinated motion machines
- Critical systems requiring redundant PLC control
Installation & Maintenance Notes
- Mount on standard 1756 ControlLogix chassis; observe proper slot layout for redundancy configurations.
- USB port for temporary local programming only; avoid use in hazardous classified areas.
- SD card retains program and firmware; keep SD card inserted during normal operation.
- Replace ESM capacitor module (1756-ESMCAP) at recommended intervals to maintain RAM retention after power loss.
- Maintain clean, non-condensing ambient environment; follow vibration and temperature limits per Rockwell manual.
- Always back up program before firmware upgrade or online edits.
FAQ
Q: Difference between 1756-L71 and 1756-L72? A: 1756-L71 = 2MB user memory; 1756-L72 = 4MB user memory for larger programs and more data tags.
Q: Does 1756-L71 have built-in Ethernet? A: No embedded Ethernet port. Network communication requires separate 1756-ENxx Ethernet module plugged into the ControlLogix chassis.
