A manufacturer-sourced guide for buyers and engineers who need to distinguish a ControlLogix catalog number from its hardware Series, firmware revision, Studio 5000 project definition and lifecycle status before approving a replacement.
In a ControlLogix system, a typed description such as “1756 input card” or “L8 controller” is not a complete purchasing specification. Rockwell Automation documentation separates the catalog number, the module’s hardware Series, the device major and minor revision, and the software environment used to configure the module. These fields answer different questions and should not be merged into one informal model name.
The ControlLogix selection guide also treats controllers, communication modules, I/O modules, chassis, power supplies, removable terminal blocks and wiring systems as distinct system elements. A correct replacement therefore depends on the complete installed configuration—not only the characters printed in large type on the front label.
Order from the complete catalog number, but verify the Series and firmware separately. For example, 1756-L85E is a catalog number. A label may additionally show Series B, while the controller or module can have a firmware revision such as 38.011. The Studio 5000 project also stores a device definition and an electronic-keying choice. Matching only “1756” or only the controller family is not sufficient.
Rockwell Automation uses 1756 as the bulletin number across the ControlLogix platform. The characters after the hyphen identify a specific controller, communication module, I/O module, chassis, power supply or accessory. Their meaning depends on the product family, so the safest process is to search the complete code in the official selection guide, product page and Product Compatibility and Download Center (PCDC).
Do not interpret each letter using a single generic alphabet chart. A letter that distinguishes a communication-module variant does not automatically carry the same meaning in an I/O module or controller. Product-family tables remain authoritative.
| Official catalog-number example | Product group shown in Rockwell literature | What the example demonstrates |
|---|---|---|
| 1756-L85E | ControlLogix 5580 controller | The complete controller catalog number must be preserved; “L8” is only a family shorthand. |
| 1756-EN2T | EtherNet/IP communication module | Network modules have their own catalog number, Series and firmware path. |
| 1756-IB16 | ControlLogix digital input module | Function and channel configuration belong to the exact I/O catalog record. |
| 1756-OB16E | ControlLogix digital output module | A near-looking suffix can identify a different module; do not omit it. |
| 1756-A10 | ControlLogix chassis | The chassis is a separate orderable system component, not part of the controller code. |
Identifies the orderable product type, such as 1756-EN2T. It maps to the product code used by electronic keying.
A letter printed on the product label, such as Series A, B, C or D. It marks a hardware-series level and can affect the supported firmware path.
A major.minor number associated with device capabilities and behavior. PCDC lists supported releases by catalog number and Series.
Rockwell Automation’s PCDC pages show why all three fields matter. For example, the same catalog family can appear with different hardware Series selections and different available firmware revisions. Redundancy release notes also list catalog number, Series and required firmware in separate columns.
1756-EN2T Series D Rev. 12.001 as only “1756-EN2T.” Keep a photograph of the full label and record all fields independently.
Rockwell Automation describes electronic keying as a method for reducing the possibility of using the wrong device in a control system. The project and installed module can be compared by vendor, device type, product code, major revision and minor revision.
The keying attributes must match. This setting gives the tightest control over catalog identity and revision.
The installed device decides whether it can emulate the configured device. Compatibility is product- and revision-specific.
Rockwell documentation warns that disabling keying can allow unintended device substitution. It must not be used as a purchasing shortcut.
The general Compatible Module rule often requires the same catalog number, with the installed device at the same or a later supported major revision. However, Rockwell explicitly notes that exact behavior varies by product family and release. Review the device’s release notes and project configuration before replacing hardware.
The bulletin number spans controllers, I/O, networks, chassis, power supplies and accessories.
The final letters or digits can distinguish a materially different catalog item.
A hardware Series letter is not the same field as a major.minor firmware revision.
A newer revision still requires product-specific compatibility and release-note review.
A project configured for Exact Match can reject a module that seems visually identical.
An I/O replacement can still fail if the RTB, wiring system, power or environmental variant is wrong.
Send Stella the complete catalog number, Series, firmware revision, nameplate photographs, Studio 5000 device definition and the installed chassis or network context.
Sales contact: Stella | Email: sales@askplc.com | Tel / WhatsApp: +86 18159889985
The 24 entries below were selected from the supplied inventory TXT files and retain the source wording. They are cross-brand industrial spare references—not replacements for a ControlLogix 1756 device. Confirm manufacturer, complete model, Series, revision and system compatibility before ordering.
| No. | Inventory reference from supplied TXT | Ordering note |
|---|---|---|
| 01 | Allen Bradley 1715-A3IO | Confirm the exact catalog and revision. |
| 02 | Allen-Bradley 1492-XIM2024-16R | Confirm terminal and wiring compatibility. |
| 03 | Allen Bradley 2711P-RDT7C /C | Confirm complete suffix and Series. |
| 04 | Allen Bradley 802T-DD | Confirm application and contact arrangement. |
| 05 | ABB UMC100 1SAJ530000R0100 | Cross-brand spare reference only. |
| 06 | ABB DIS0002 2RAA005802A0001H | Cross-brand spare reference only. |
| 07 | ABB AI835A 3BSE051306R1 | Cross-brand spare reference only. |
| 08 | ABB CI840A 3BSE041882R1 | Cross-brand spare reference only. |
| 09 | 6ES7322-1BL00-0AA0 | Confirm Siemens family and full configuration. |
| 10 | 6ES7153-2BA02-0XB0 | Confirm Siemens family and full configuration. |
| 11 | 6ES7221-1BF32-0XB0 | Confirm Siemens family and full configuration. |
| 12 | S7-400 PS 20A- 6EP8090-0CA00 | Confirm complete model and system power requirements. |
| 13 | 330730-080-00-05 | Confirm manufacturer and complete measurement chain. |
| 14 | 3300XL 144181-51 | Confirm manufacturer and complete measurement chain. |
| 15 | 3300 81672-01 | Confirm manufacturer and complete measurement chain. |
| 16 | 330105-02-12-10-02-05 | Confirm full suffix and system compatibility. |
| 17 | KJ2003X1-BA2 12P2093X112 | Confirm Emerson system and revision. |
| 18 | KJ4110X1-BA1 | Confirm Emerson system and revision. |
| 19 | VE801 | Confirm manufacturer and complete order code. |
| 20 | CC-PAOH01 51405039-175 | Confirm Honeywell system and revision. |
| 21 | FC-TSHART-1620M | Confirm Honeywell system and revision. |
| 22 | MU-NKD005 | Confirm Honeywell system and revision. |
| 23 | GE IC200ALG620-FD | Confirm GE system and complete revision. |
| 24 | GE IC200MDL940A | Confirm GE system and complete revision. |
It is the Rockwell Automation bulletin number used across the ControlLogix product family. It does not identify one exact module by itself.
No. Series is a hardware-series letter. Firmware is normally expressed as a major.minor numeric revision and must be checked separately.
No. “L8” is a family shorthand. Provide the full controller catalog number, Series, firmware revision and project requirements.
No. Review PCDC, the product release notes, Studio 5000 support and any redundancy, safety or process requirements before approving a change.
Rockwell documentation lists vendor, device type, product code, major revision and minor revision among the attributes used for keying.
No. The installed device determines whether it can emulate the configured device, and the rule is product- and revision-specific.
Do not use Disable Keying as a procurement shortcut. Rockwell warns that incorrect keying choices can permit unintended device substitution and create operational risk.
Use Rockwell Automation’s Product Compatibility and Download Center, selecting the complete catalog number and hardware Series.
Capture the full catalog number, Series, revision or firmware information, serial number and any environmental or certification suffix visible on the unit.
Yes. Rockwell’s selection guide treats RTBs and wiring systems as separately selected items for I/O modules.
No. Lifecycle status and compatibility are different decisions. Verify form, fit, function, firmware, software, wiring and project configuration.
Include the complete catalog number, Series, firmware revision, quantity, condition requirement, nameplate photos, Studio 5000 version, chassis/slot, connected accessories and delivery destination.
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