Allen-Bradley Programmable Logic Controller: Complete Guide 2026
Complete guide to Allen-Bradley programmable logic controllers: ControlLogix, CompactLogix, Micro800, MicroLogix, and SLC 500 families. Compare capabilities, pricing, programming environments, and how to choose.
Allen-Bradley programmable logic controllers — the hardware brand sold by Rockwell Automation — dominate North American manufacturing. If you work in a US or Canadian plant, there's a strong chance the PLC cabinet has an Allen-Bradley name on it. This guide covers the complete 2026 AB product line, from the $200 Micro800 entry-level family through the enterprise-grade ControlLogix systems that run major automotive lines, packaging plants, and petrochemical process skids.
Allen-Bradley Is a Hardware Brand of Rockwell Automation
Two terms that mean the same thing in practice:
- Allen-Bradley — the historic brand name stamped on the hardware
- Rockwell Automation — the parent company that makes and sells it
When people say "Allen-Bradley PLC", they mean a PLC manufactured by Rockwell. The brand has been around since 1903; Rockwell acquired Allen-Bradley in 1985. New product boxes still carry the Allen-Bradley brand mark alongside the Rockwell Automation corporate identity.
The Modern Allen-Bradley Logix Family
Three active product lines make up the Logix family — the modern tag-based Allen-Bradley platform that handles all new installations.
Micro800 — Entry Level
- Best for: small OEM machines, packaging sub-assemblies, standalone equipment with simple logic
- Models: Micro820, Micro830, Micro850, Micro870
- I/O: 10 on-board (Micro820) up to 88 total (Micro850 + expansion)
- Pricing: $200–$800 per CPU
- Programming: Connected Components Workbench (CCW) — free download from Rockwell
- Communications: Ethernet/IP (scanner on Micro850/870), Modbus RTU/TCP, Profinet (via add-on)
CompactLogix — Mid-Tier
- Best for: mid-sized machines, conveyor systems, packaging lines, tier-one automotive cells
- Models: CompactLogix 5370, 5380, 5480 (Programmable Automation Controller, PAC)
- I/O: 200 to several thousand via expansion
- Pricing: $1,500–$6,000 per CPU
- Programming: Studio 5000 Logix Designer (paid — ~$2,500–$8,000/yr for Studio 5000 Standard/Professional)
- Communications: EtherNet/IP, DeviceNet, ControlNet, integrated Ethernet ports
ControlLogix — Enterprise / Large Process
- Best for: large process plants, refineries, enterprise manufacturing, automotive assembly plants
- Models: ControlLogix 5570, 5580 (current)
- I/O: up to 128,000 I/O via EtherNet/IP distributed I/O (FLEX, POINT I/O)
- Pricing: $5,000–$20,000+ per CPU
- Programming: Studio 5000 Logix Designer
- Variants: Standard, GuardLogix (safety PL d / PL e / SIL 3), Process (PlantPAx integrated), Redundant
- Communications: full EtherNet/IP, ControlNet, DeviceNet, OPC UA server option
Legacy Allen-Bradley PLCs (Still in Production Plants)
These product lines are phased out for new builds but still running in thousands of operational plants. Engineers working in US manufacturing encounter them constantly.
MicroLogix 1100, 1400, 1200, 1000
- Small controllers, rack-based
- Programmed in RSLogix 500 (legacy IDE, not Studio 5000)
- Address-style programming:
I:1/0,O:2/0,B3:0/0— not tag-based - Micrologix 1000 is end-of-life; 1200 discontinued; 1100 and 1400 still sold for maintenance
- Replacement path: Micro800 for new projects, though not a drop-in swap
SLC 500
- Mid-scale rack PLC, dominant in US manufacturing from 1990s–2010s
- Programmed in RSLogix 500 (same tool as MicroLogix)
- Programming style: address-based, similar to MicroLogix
- Officially discontinued; spare parts still available
- Replacement path: CompactLogix with RSLogix 500 Emulate for legacy project migration
PLC-5 (historical)
- Rack PLC from the 1980s–1990s
- Programmed in RSLogix 5 (yes, that's the name — different from 500 and 5000)
- Mostly retired; a handful of legacy plants still maintain them
- Replacement path: ControlLogix with migration tooling
Allen-Bradley Programming Software
Studio 5000 Logix Designer (Modern)
The flagship IDE. Covers all Logix controllers: ControlLogix, CompactLogix, FlexLogix, SoftLogix, GuardLogix, Micro800 (with limitations). Licensed annually.
Editions and pricing (2026):
- Standard: $2,500/year
- Professional: $5,500–$8,000/year
- Lite (for Micro800): typically bundled
- Safety Advanced: add-on for GuardLogix, additional ~$2,500/year
Studio 5000 integrates design across multiple disciplines — PLC logic (Logix Designer), HMI (FactoryTalk View), Motion (Logix Designer Motion), and Drive configuration — into a single project file.
Connected Components Workbench (CCW)
Free download from Rockwell. Programs Micro800 controllers and PowerFlex drives. Basic IDE aimed at OEMs building small-machine products.
RSLogix 500
Legacy IDE for SLC 500 and MicroLogix families. Still sold and maintained for brownfield work. Can't open Studio 5000 projects (different file format).
RSLogix 5000 (old name)
The predecessor of Studio 5000 Logix Designer. Older engineers still refer to "RSLogix 5000" even though the current product is Studio 5000. Functionally the same product line. Rockwell maintains backward file compatibility.
Emulate 5000 / Emulate 500
Optional standalone emulators for testing Logix / SLC projects without hardware. Licensed separately; typically $2,000+ for Logix Emulate.
Allen-Bradley Communications Protocols
EtherNet/IP — Rockwell's native Industrial Ethernet protocol, running CIP (Common Industrial Protocol) over standard Ethernet. Used for PLC-to-PLC, PLC-to-drive (PowerFlex), PLC-to-HMI (PanelView), and distributed I/O (FLEX, POINT I/O, ArmorBlock).
ControlNet — Older deterministic coaxial bus, still installed in many plants. Being phased out in favour of EtherNet/IP.
DeviceNet — CAN-based device-level network. Still in use for conveyor sensors and simple I/O in many plants.
OPC UA — Native server option on ControlLogix 5580 firmware v36+ and CompactLogix 5480. Used for SCADA and IT integration.
Modbus RTU / TCP — Supported via add-on messaging instructions or third-party bridges. Not native.
PROFINET — Not native; requires Anybus or HMS gateways.
How to Choose an Allen-Bradley PLC
1. What's the I/O count?
- Under 40: Micro800 (Micro830 or Micro850)
- 40–200: CompactLogix 5370 or smaller CompactLogix 5380
- 200–4,000: CompactLogix 5380 / 5480
- 4,000+: ControlLogix 5580
2. What's the budget?
- Tight: Micro800 + CCW (free IDE). Total system $500–$1,500 for small machines.
- Standard: CompactLogix + Studio 5000. Total system $3,000–$8,000 for mid machines.
- Enterprise: ControlLogix + Studio 5000 Professional + redundancy. Total system $20,000+ per CPU cabinet.
3. Safety requirement?
- No safety beyond E-stops: any Logix + a hardwired safety relay.
- PL d–PL e safety functions: GuardLogix (safety variant of ControlLogix) or CompactGuardLogix.
- Micro800 does not have a safety-rated variant.
4. Motion requirement?
- No motion: any Logix + standalone drives.
- Servo / multi-axis coordinated motion: CompactLogix 5380 or ControlLogix 5580 with Kinetix servo drives over EtherNet/IP.
5. Brownfield vs greenfield?
- New project: start with Micro800 (small) or Studio 5000 / CompactLogix (mid). Don't specify legacy SLC for new builds.
- Existing SLC 500 maintenance: keep RSLogix 500 and SLC 500 hardware as-is; plan phased CompactLogix migration.
Typical Allen-Bradley Plant Architecture
A mid-tier packaging plant using Allen-Bradley might look like:
- ControlLogix managing the overall line coordination and safety (GuardLogix for E-stop zones)
- Multiple CompactLogix controllers per machine, each managing a specific sub-assembly
- EtherNet/IP as the backbone for all PLC-to-PLC, PLC-to-drive, PLC-to-I/O traffic
- POINT I/O distributed I/O blocks for sensor clusters
- PowerFlex drives for motor control
- PanelView 5310 / 5510 HMIs for operator stations
- FactoryTalk View SE running SCADA on a Windows server
- FactoryTalk Historian logging data to SQL
- OPC UA pushing key KPIs to plant MES
Buying Allen-Bradley PLCs
- Distributor network: buy through authorised Rockwell distributors — Kendall Electric, Graybar, RS, McNaughton-McKay, Revere Electric are major North American ones.
- Lead times in 2026: Micro800 and most CompactLogix in stock. ControlLogix and specialty variants (GuardLogix, redundant) have 4–16 week lead times.
- Second-hand market: active for legacy SLC 500 and MicroLogix. New projects should buy new.
Allen-Bradley vs Siemens: The Pragmatic Choice
Both vendors provide equivalent capability at equivalent price points. The real choice is driven by region and installed base, not raw technical comparison. In US and Canadian plants, Allen-Bradley dominates; in European and global process industries, Siemens does. Plants running one brand rarely switch because the retraining and parts-stocking overhead outweighs any per-unit savings. See our Siemens vs Allen-Bradley comparison for the detailed decision framework.
Key Takeaways
- Allen-Bradley programmable logic controllers are the brand name for Rockwell Automation's PLC line.
- The modern family has three active tiers: Micro800 (small), CompactLogix (mid), ControlLogix (enterprise).
- Legacy families (SLC 500, MicroLogix, PLC-5) are still in many plants but phased out for new builds.
- Studio 5000 Logix Designer is the modern IDE; RSLogix 500 maintains the legacy SLC/MicroLogix lines; Connected Components Workbench is free for Micro800.
- EtherNet/IP is the native protocol; OPC UA is available on newer CPUs for IT integration.
- Studio 5000 licensing is a meaningful cost ($2,500–$8,000/year); budget this into project planning.
