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Every Allen-Bradley part number is a compressed spec sheet. Once you know how to read it, you can identify the platform, module function, I/O capacity, voltage rating, and communication protocol without ever opening a datasheet. This saves time when ordering replacements, cross-referencing spares, or verifying that the module on the shelf actually matches the one in the rack.
This guide breaks down the catalog number structure for four of the most commonly ordered Allen-Bradley series: 1756 (ControlLogix), 2080 (Micro800), 5069 (Compact 5000), and 25B (PowerFlex 525).
How Allen-Bradley catalog numbers are structured
Rockwell Automation follows a consistent pattern across most product families. A catalog number is built from left to right, with each segment adding more specificity:
| Segment | What It Tells You | Example |
|---|---|---|
| Series Prefix | Product family and platform | 1756 = ControlLogix |
| Module Type Code | Function: CPU, input, output, analog, power supply, comms | L = processor, IF = analog input |
| Capacity / Model | I/O point count, channel count, or processor model number | 16 = 16 points, 83 = model 83 |
| Feature Suffix | Voltage, protocol, isolation, fusing, duty rating | E = EtherNet/IP, I = isolated |
The separator between the prefix and the rest is always a hyphen. Some families (like PowerFlex drives) pack additional data into a longer suffix string. Let's decode each series.
1756 Series: ControlLogix
The 1756 platform is Rockwell's flagship for large-scale, rack-based control. The catalog number format is:
1756 - [Type Code][Capacity][Suffix]
Common 1756 type codes
| Code | Module Type | Examples |
|---|---|---|
| L | Processor (CPU) | 1756-L83E, 1756-L85E |
| IB | DC Digital Input | 1756-IB16, 1756-IB32 |
| IA | AC Digital Input | 1756-IA16, 1756-IA32 |
| OB | DC Digital Output | 1756-OB16E, 1756-OB32 |
| OA | AC Digital Output | 1756-OA16 |
| OW | Relay Output | 1756-OW16I |
| IF | Analog Input (voltage/current) | 1756-IF8, 1756-IF8I |
| OF | Analog Output (voltage/current) | 1756-OF8 |
| IT | Thermocouple Input | 1756-IT6I |
| IR | RTD Input | 1756-IR6I |
| PA / PB | AC / DC Power Supply | 1756-PA72, 1756-PB72 |
| EN | EtherNet/IP Communication | 1756-EN2T, 1756-EN4TR |
| CN | ControlNet Communication | 1756-CN2R |
| A | Chassis | 1756-A4, 1756-A7, 1756-A13 |
Common 1756 suffixes
| Suffix | Meaning |
|---|---|
| E (on processors) | EtherNet/IP port built-in |
| E (on I/O modules) | Electronically fused outputs |
| I | Isolated (channel-to-channel isolation) |
| H | High-density or conformal coated |
| S | Safety-rated (SIL 3 / PLe) |
| T | Dual-port (on EtherNet/IP modules) |
Decode example: 1756-L83E
| Segment | Value | Meaning |
|---|---|---|
| Series | 1756 | ControlLogix platform |
| Type | L | Processor (Logix5580) |
| Model | 83 | Model 83 (40 MB memory, high performance) |
| Suffix | E | Built-in EtherNet/IP port |
Translation: ControlLogix Logix5580 processor, model 83, with integrated EtherNet/IP. This is one of the higher-end ControlLogix CPUs with 40 MB user memory.
View the 1756-L83E in our inventory
Decode example: 1756-OB16E
| Segment | Value | Meaning |
|---|---|---|
| Series | 1756 | ControlLogix platform |
| Type | OB | DC Digital Output |
| Points | 16 | 16 output points |
| Suffix | E | Electronically fused |
Translation: ControlLogix 16-point DC digital output module with electronic fusing. The "E" suffix on I/O modules means each output channel has built-in electronic short-circuit protection instead of requiring external fuses.
View the 1756-OB16E in our inventory
Decode example: 1756-IF8I
| Segment | Value | Meaning |
|---|---|---|
| Series | 1756 | ControlLogix platform |
| Type | IF | Analog Input (voltage/current) |
| Channels | 8 | 8 analog input channels |
| Suffix | I | Channel-to-channel isolation |
Translation: ControlLogix 8-channel isolated analog input module. The "I" suffix means each channel is electrically isolated from the others, which is critical in process applications where sensors operate at different ground potentials.
View the 1756-IF8I in our inventory
2080 Series: Micro800
The Micro800 family uses a longer, more compressed catalog number format that packs the controller model, I/O count, and feature set into a single string after the hyphen:
2080 - [Controller Model][I/O Count][Features]
2080 controller models
| Code | Controller |
|---|---|
| LC10 | Micro810 (ultra-compact, no expansion) |
| LC20 | Micro820 (small, EtherNet/IP capable) |
| LC30 | Micro830 (mid-range, plug-in I/O) |
| LC40 | Micro840 (advanced, FBD/SFC support) |
| LC50 | Micro850 (top-tier, full instruction set) |
2080 feature suffixes
| Character | Meaning |
|---|---|
| Q | DC inputs/outputs |
| R | Relay outputs |
| W | EtherNet/IP port |
| B | DC power supply (24VDC) |
| A | AC power supply (120/240VAC) |
Decode example: 2080-LC20-20QWB
| Segment | Value | Meaning |
|---|---|---|
| Series | 2080 | Micro800 platform |
| Controller | LC20 | Micro820 |
| I/O Count | 20 | 20 embedded I/O points (12 DI + 8 DO) |
| Q | DC | DC I/O (sinking/sourcing) |
| W | EtherNet | Built-in EtherNet/IP port |
| B | Power | 24VDC power supply |
Translation: Micro820 controller with 20 embedded DC I/O points, built-in EtherNet/IP, powered by 24VDC. This is one of the most popular Micro800 models for small machine control and IoT gateway applications.
View the 2080-LC20-20QWB in our inventory
5069 Series: Compact 5000 (CompactLogix 5380/5480)
The 5069 platform is Rockwell's latest mid-range system. Catalog numbers follow a similar pattern to 1756 but include network topology suffixes:
5069 - [Type Code][Model/Capacity][Network Suffix]
Common 5069 type codes
| Code | Module Type |
|---|---|
| L | Processor (CompactLogix 5380) |
| IB | DC Digital Input |
| OB | DC Digital Output |
| IF | Analog Input |
| OF | Analog Output |
| FPD | Field Potential Distributor |
5069 network suffixes
| Suffix | Meaning |
|---|---|
| E | EtherNet/IP |
| RM | DLR (Device Level Ring) — single-ring network resilience |
| RS | PRP (Parallel Redundancy Protocol) — dual-ring |
| RM2 | DLR with dual EtherNet/IP ports |
Decode example: 5069-L340ERM
| Segment | Value | Meaning |
|---|---|---|
| Series | 5069 | Compact 5000 platform |
| Type | L | Processor (CompactLogix 5380) |
| Model | 340 | Model 340 (4 MB memory, mid-range performance) |
| E | EtherNet | Dual EtherNet/IP ports |
| RM | Topology | DLR ring support |
Translation: CompactLogix 5380 processor, model 340, with dual EtherNet/IP ports and DLR ring topology support. The 5380 platform uses the same Studio 5000 programming environment as ControlLogix, so it fits mid-size applications that don't need the rack-based scalability of 1756.
View the 5069-L340ERM in our inventory
25B Series: PowerFlex 525 Drives
PowerFlex drives use a different catalog structure than PLC modules. The part number encodes voltage class, current rating, duty type, and hardware version:
25B - [Voltage][Current Rating][Duty][Version]
25B voltage codes
| Code | Voltage Class |
|---|---|
| A | 100-120V, 1-phase |
| B | 200-240V, 1-phase |
| D | 380-480V, 3-phase |
| E | 500-600V, 3-phase |
25B duty codes
| Code | Duty Rating |
|---|---|
| N | Normal duty (constant torque applications like conveyors) |
| H | Heavy duty (variable torque applications like fans/pumps) |
Decode example: 25B-D010N104
| Segment | Value | Meaning |
|---|---|---|
| Series | 25B | PowerFlex 525 |
| Voltage | D | 380-480V, 3-phase input |
| Current | 010 | 10A rated output current |
| Duty | N | Normal duty |
| Version | 104 | Hardware version 104 |
Translation: PowerFlex 525 drive, 480V 3-phase, 10A output (4 kW / 5 HP at normal duty), hardware version 104. The three-digit current code lets you quickly calculate approximate horsepower: at 480V, every 2.5A is roughly 1.5 kW (2 HP).
View the 25B-D010N104 in our inventory
Quick-reference cheat sheet
| Series Prefix | Platform | Application | Pattern |
|---|---|---|---|
| 1756 | ControlLogix | Large-scale, rack-based control | 1756-[Type][Count][Suffix] |
| 1769 | CompactLogix (legacy) | Mid-range, book-style I/O | 1769-[Type][Count][Suffix] |
| 2080 | Micro800 | Small standalone machines | 2080-[Model][Count][Features] |
| 5069 | Compact 5000 | Modern mid-range (5380/5480) | 5069-[Type][Model][Network] |
| 5094 | FLEX 5000 | Distributed I/O | 5094-[Type][Count][Suffix] |
| 20F1 | PowerFlex 755T | High-performance drives | 20F1-[Voltage][Current][Options] |
| 25B | PowerFlex 525 | General-purpose drives | 25B-[Voltage][Current][Duty][Ver] |
Common mistakes when reading catalog numbers
A few pitfalls that trip up even experienced technicians:
- "E" means different things depending on the product: On a 1756-L83E processor, the E means EtherNet/IP port. On a 1756-OB16E output module, the E means electronically fused. Always consider the module type when interpreting suffixes.
- The number after the type code is not always I/O points: On processors (L-type), the number is a model identifier, not a point count. 1756-L83E has 40 MB of memory, not 83 I/O points.
- Don't confuse 1769 with 5069: Both are CompactLogix platforms, but 1769 is the legacy series (Logix 5370) and 5069 is the current generation (Logix 5380/5480). They are not interchangeable — different backplanes, different I/O modules.
- PowerFlex current codes are not horsepower: 25B-D010 means 10 amps, not 10 HP. You need to factor in the voltage class and duty rating to get the HP/kW equivalent.
How to Look Up an Allen-Bradley Part Number
If you have a catalog number and need to confirm the full specifications:
- Rockwell Product Catalog: Visit rockwellautomation.com/products and enter the catalog number in the search bar. This gives you the official datasheet, user manual, and firmware compatibility.
- Rockwell Compatibility & Downloads (PCDC): The Product Compatibility & Download Center shows firmware versions, series compatibility, and what modules work together in the same chassis or network.
- Check our inventory: Search our Allen-Bradley collection for in-stock availability and pricing. We carry processors, I/O modules, power supplies, and communication modules across the 1756, 2080, and 5069 families.
Related Resources
- Allen-Bradley PLC Buyer's Guide: ControlLogix vs CompactLogix vs Micro800
- ControlLogix 1756 Fault Codes: Quick Diagnosis Guide
- PLC-5 to ControlLogix Migration Guide
Looking for a specific Allen-Bradley part number? Browse our full Allen-Bradley inventory or search for your catalog number directly. We stock modules across the 1756 ControlLogix platform and more, all with a 2-year warranty and same-day shipping on in-stock items.
Frequently Asked Questions
What does the "E" mean at the end of an Allen-Bradley 1756 part number?
It depends on the module type. On processors like the 1756-L83E, the "E" indicates a built-in EtherNet/IP port. On I/O modules like the 1756-OB16E, the "E" means the outputs are electronically fused with built-in short-circuit protection. Always check the module type code (L for processor, OB for output) to interpret the suffix correctly.
How do I determine the horsepower of a PowerFlex 525 from the catalog number?
The three-digit number after the voltage code is the rated output current in amps, not horsepower. For example, 25B-D010N104 outputs 10A at 480V. To estimate HP, multiply amps by voltage by 1.732 (for 3-phase) and divide by 746. In this case: 10A at 480V equals approximately 5 HP at normal duty. The duty code (N = normal, H = heavy) also affects the HP rating.
What is the difference between 1769 and 5069 series CompactLogix?
Both are mid-range Allen-Bradley PLC platforms, but they are different generations. The 1769 series runs Logix 5370 controllers (CompactLogix 5370) and uses book-style I/O modules. The 5069 series runs Logix 5380/5480 controllers with significantly more memory, faster processing, and modern Compact 5000 I/O modules. They use different backplanes and are not physically interchangeable.
Can I mix different 1756 module series (Series A, B, C) in the same chassis?
Generally yes, as long as the modules share a compatible firmware revision and the chassis power supply can handle the combined current draw. However, you should always verify compatibility using Rockwell's Product Compatibility & Download Center (PCDC). Some older Series A modules may not work with the latest processors, and vice versa.
Where can I find the series letter on an Allen-Bradley module?
The series letter is printed on the module label, usually near the catalog number — for example, "1756-L83E Series A." It is also stamped on the side or bottom of the module housing. In Studio 5000, you can see the series designation in the module properties when you go online. The series letter is important for firmware compatibility and ordering exact replacements.