Allen-Bradley 1756-L81E ControlLogix Processor 3 MB
In stock: 3 units in Milwaukee, WI. Physically stocked and ready to ship or available for local pickup. Includes a 1-year full-function warranty.
3 MB ControlLogix 5580 controller · embedded 1 Gb EtherNet/IP port
Actual NJT inventory photos
Starting at
$2,499.99USD
Refurbished and unused surplus options available
| Part Number | 1756-L81E |
| Description | ControlLogix 5580 controller, 3 MB. In stock in refurbished and unused surplus condition, Series B. |
| Shipping | Ships same or next business day UPS Ground included | Next-Day Air and Worldwide Shipping available at checkout |
| Pickup | Free local pickup at 2122 N Prospect Ave. Call ahead at (414) 331-5954. |
| Warranty | 1-year full-function warranty provided by NJT Automation. Warranty details
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| Returns | 90-day free returns. View return policy |
| Exchange | Send us your defective 1756-L81E after your purchase for a 10% core credit (from $250). We also purchase old or damaged parts outright. |
Replacement Options for 1756-L81E
Pick a condition and series below. UPS Ground shipping included.
| Variants | Part NumberConditionSeriesQtyPrice 1756-L81E /B$2,499.99 Refurbished · Series B · 1 in stock1756-L81E /BRefurbishedSeries B1$2,499.99 USD 1756-L81E /B$3,799.99 New surplus (sealed) · Series B · 2 in stock1756-L81E /BNew surplus (sealed)Series B2$3,799.99 USD 1756-L81ES /B$3,499.99 New surplus (sealed) · Series B · 2 in stock1756-L81ES /BNew surplus (sealed)Series B2$3,499.99 USD | ||||||||||||||||||||||||||||||||
| Availability | 3 units in stock | ||||||||||||||||||||||||||||||||
| Repairs | 1756-L81E Mail-In Repair ServiceEstimated: $1,440.00 | ||||||||||||||||||||||||||||||||
Part Number Decoder | ControlLogix 5580 controller 1756L81E
Decoded from the Rockwell Automation catalog-number structure. Series and firmware revision are printed on the product label, not encoded here. | ||||||||||||||||||||||||||||||||
Series & Revisions | Series B in stock; other series on request. Series B controllers run firmware revision 31.011 or later; Series A units also run the earlier 5580 revisions (28 to 30). Every series needs a Series B or Series C 1756 chassis (Series B derated to 50 °C ambient); 5580 controllers do not work in a Series A chassis. Series notes: Studio 5000 keys on catalog number and firmware revision, not series. Fitting a Series B into a project on revision 28 to 30 means upgrading the project to 31 or later first. | ||||||||||||||||||||||||||||||||
Intended Use | Designed for plant-wide discrete, process, and motion control applications. ControlLogix controllers run high I/O-count machines, batch and continuous process lines, and coordinated multi-axis motion from a single chassis, with redundancy and plant-network connectivity when the application calls for it. Typical homes are automotive and tire plants, food and beverage lines, water and wastewater, oil and gas skids, and large packaging systems. | ||||||||||||||||||||||||||||||||
Physical Data | Weight and DimensionsWeight0.87 lb (0.39 kg)H × W × D5.7 × 1.4 × 5.7 in. (145 × 35 × 145 mm)
Product weight and dimensions are typical manufacturer-published values and may differ by series or option. Shipping box and weight are estimates for freight planning; the packed unit may ship in a different box. | ||||||||||||||||||||||||||||||||
Similar Part Numbers | |||||||||||||||||||||||||||||||||
Allen Bradley Information | Technical Specifications15 parameters from manufacturer-published specifications
Typical manufacturer-published values for this catalog number; confirm against the current manufacturer documentation before specifying. | ||||||||||||||||||||||||||||||||
| Category | ControlLogix | ||||||||||||||||||||||||||||||||
| UPC / GTIN | 887172361326 | ||||||||||||||||||||||||||||||||
| Part Number | 1756-L81E | ||||||||||||||||||||||||||||||||
| Manufacturer | Allen-Bradley | ||||||||||||||||||||||||||||||||
Previously sold 1756-L81E10 sold
NJT Automation has supplied and shipped 10 1756-L81E ControlLogix 5580 controllers since 2024; these listings are sold and the in-stock options above are ready to ship.
- Sold
- 10 since 2024
- Series
- B × 10
Can the 1756-L81E be repaired?
Yes. NJT Automation repairs the 1756-L81E by mail-in: diagnostic evaluation, component-level repair and a functional test, backed by a 1-year full-function warranty.
NJT managed repair. No evaluation fee; no repair, no charge. Prepaid UPS label both ways, $650 minimum, rush available. 1-year full-function warranty included, 2- and 3-year options.
Compare quotes from independent repair technicians. Post your repair on RepairMode to receive competitive bids from experienced technicians. Each technician sets their own pricing and warranty.
View completed 1756-L81E repairson RepairMode.com ↗Common failures
Failure patterns we regularly see on ControlLogix 5580 controller hardware like the 1756-L81E:
- SD card corruption: controller reports a load failure or comes up with no project
- Controller will not boot or shows a solid red OK LED (nonrecoverable major fault) after a power event
- Repeated major faults after a firmware flash that did not complete
- Overheating in a full chassis, especially with no spacing in sealed enclosures
- Four-character status display stuck, blank or showing scrolling fault text
Photos by NJT Automation; test videos from NJT or network repair technicians.
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