Purchase now: Allen-Bradley 1756-L71 ControlLogix Controller
Purchase now: Atlantechdrives provides you the 1756-L71, an elite, high-performance programmable automation controller (PAC) from the highly respected ControlLogix 5570 family, engineered by the global automation leaders at Rockwell Automation. Designed to handle the most demanding manufacturing operations in the world, the 1756-L71 is equipped with 2 Megabytes of dedicated user memory and 0.98 Megabytes of dedicated I/O data memory. This controller acts as the central intellectual brain of massive automation architectures, seamlessly executing advanced process control PID loops, highly complex discrete manufacturing logic, and high-speed multi-axis CIP Motion instructions simultaneously without missing a single scan cycle. Capable of supporting up to 500 Ethernet/IP nodes and seamlessly bridging networks via ControlNet and DeviceNet, this processor is the absolute industry standard for automotive assembly plants, massive food and beverage packaging lines, and heavy-duty steel manufacturing where uninterrupted computational speed and reliability are strictly mandatory.
Technical Specifications of the 1756-L71
The 1756-L71 utilizes a dual-core architecture to separate background communication tasks from direct logic execution, ensuring that incoming network traffic never slows down critical machine response times.
- Part Number: 1756-L71
- Controller Family: ControlLogix 5570
- User Memory: 2 MB
- I/O Memory: 0.98 MB
- Programming Port: USB 2.0 (Type B)
- Non-Volatile Storage: 1 GB Secure Digital (SD) Card included
- Energy Storage: Energy Storage Module (ESM) – Capacitor-based
- Supported Software: RSLogix 5000 (v20+) or Studio 5000 Logix Designer
Expert Tips: The Revolution of the Energy Storage Module (ESM)
Older generations of programmable controllers relied on internal lithium batteries to keep the RAM active and prevent program loss during a factory power outage. Expert Tip: The 1756-L71 completely eliminates the massive maintenance headache of dead PLC batteries by utilizing an advanced Energy Storage Module (ESM), part number 1756-ESMCAP. This module houses high-capacity industrial supercapacitors. When the factory power fails, the ESM instantly provides just enough electrical juice to power the CPU for roughly 30 seconds. During this crucial time window, the controller rapidly writes the entire contents of its volatile RAM directly onto the included non-volatile SD Card. When power is restored, the CPU loads the program back from the SD Card and resumes operation flawlessly. You never have to schedule a lithium battery replacement or worry about losing a program overnight again.
Installation Advice: USB Port Utilization
The front panel of the 1756-L71 features a highly convenient USB 2.0 port, replacing the older, much slower RS-232 serial ports found on legacy L6 controllers. This port provides blisteringly fast firmware flashing and program downloads during the initial machine commissioning phase. However, engineers must clearly understand that this USB port is strictly designed for temporary, local programming access. It lacks the robust electrical isolation required for a permanent industrial network connection. Never leave a laptop or a permanent HMI plugged into this USB port while the machine is in continuous production, as a sudden electrical surge or severe static discharge could travel up the USB cable and instantly destroy the internal logic board.
Frequently Asked Questions (FAQs)
Q: Can the 1756-L71 be used in a redundant processor configuration?
A: Yes. The 1756-L71 fully supports high-availability ControlLogix Redundancy configurations. By pairing two identical L71 controllers in separate chassis connected via redundant fiber optic modules, the primary CPU will seamlessly and instantly failover to the secondary CPU if a hardware fault occurs, ensuring absolutely zero process downtime.
Q: Does this controller have a built-in Ethernet port on the front?
A: No. Unlike the newer 5580 (L8) series controllers, the 1756-L71 requires a separate communication bridge module, such as a 1756-EN2T or 1756-EN3TR, installed in the same chassis to communicate over an EtherNet/IP network.
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