The Allen-Bradley 1756-L81E is an entry-level processor in the ControlLogix 5580 series, Rockwell Automation's high-performance programmable automation controller platform. The controller supports up to 100 EtherNet/IP nodes (with Logix Designer v30+) and 256 motion axes via Integrated Motion on EtherNet/IP.
Item No :
1756-L81EOrder(MOQ) :
1 PiecePayment :
EXWProduct Origin :
USAShipping Port :
WuhanLead Time :
3~5 daysWeight :
3kg| Specification | Description |
|---|---|
| Manufacturer | Rockwell Automation (Allen-Bradley) |
| Model | 1756-L81E |
| Product Family | ControlLogix 5580 |
| Product Type | Programmable Automation Controller (PAC) |
| User Memory | 3 MB |
| Nonvolatile Memory | 2 GB Secure Digital (SD) card, pre-installed (1784-SD2) |
| Embedded Ethernet Port | 1 x RJ45, 10/100/1000 Mbps (1 Gb) |
| Local Programming Port | 1 x USB 2.0 Full-Speed, Type B |
| EtherNet/IP Nodes Supported | 50 (Logix Designer v29) / 100 (Logix Designer v30+) |
| Motion Axes Supported | 256 (Integrated Motion on EtherNet/IP) |
| Max Digital I/O | 128,000 points |
| Max Analog I/O | 4,000 points |
| Controller Tasks | 32 tasks; 1,000 programs/task |
| Programming Languages | LD, ST, FBD, SFC |
| Backplane Current Draw | 1.20 A @ 5.1V DC; 5 mA @ 1.2V DC |
| Power Dissipation | 6.2 W max |
| Thermal Dissipation | 21.2 BTU/hr |
| Isolation Voltage | 50V continuous (basic insulation) |
| Operating Temperature | 0°C to +60°C |
| Module Location | Any slot in 1756 ControlLogix chassis |
| Weight | Approx. 0.55 kg (1.21 lbs) |
| Certifications | CE, UL, ATEX, KC, Marine |
| Lifecycle Status | Active |
| Model | User Memory | EtherNet/IP Nodes | Description |
|---|---|---|---|
| 1756-L81E (this model) | 3 MB | 100 (v30+) | Entry-level 5580 controller |
| 1756-L81ES | 3 MB + 1.5 MB safety | 100 | GuardLogix 5580 safety controller |
| 1756-L82E | 5 MB | 175 (v30+) | Mid-range 5580 controller |
| 1756-L83E | 10 MB | 250 (v30+) | Upper mid-range 5580 controller |
| 1756-L84E | 20 MB | 250 (v30+) | High-end 5580 controller |
| 1756-L85E | 40 MB | 300 (v28+) | Flagship 5580 controller |
| 1756-L81EK | 3 MB | 100 | Conformal-coated version |
| 1756-L81EXT | 3 MB | 100 | Extended temperature version |
Q1: What is the primary function of the 1756-L81E?
It is an entry-level ControlLogix 5580 controller that serves as the central processing unit for small to medium-scale industrial automation systems. It executes user logic, manages I/O and motion control over EtherNet/IP, and provides modern networking capability with its built-in 1 Gb Ethernet port.
Q2: Does the 1756-L81E have a built-in Ethernet port?
Yes. Unlike the older 5570 series (which required a separate communication module), the 5580 series features a built-in 1 Gb (Gigabit) Ethernet port on the front of the controller. This port supports EtherNet/IP communication at 10/100/1000 Mbps speeds.
Q3: How many EtherNet/IP nodes does the 1756-L81E support?
The node capacity depends on the Studio 5000 Logix Designer version:
50 nodes with Logix Designer version 29
100 nodes with Logix Designer version 30 or later
Q4: Can the 1756-L81E be used in a redundant (ControlLogix Redundancy) system?
No. According to the official ControlLogix selection guide, controller redundancy is not supported on 5580 series controllers — it is listed as a future capability. For redundant applications, the 1756-L7x series (e.g., 1756-L71, L72, L73, L74, L75) must be used with the 1756-RM2 redundancy module.
Q5: What is the difference between the 1756-L81E and the 1756-L81ES?
The 1756-L81E is the standard controller with 3 MB user memory. The 1756-L81ES is the GuardLogix safety controller with 3 MB standard memory plus 1.5 MB safety memory, certified for safety applications up to SIL 3/PLe. The L81ES supports both standard and safety tasks, while the L81E does not have integrated safety capability.
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