Siemens and Allen-Bradley dominate the global PLC market, together commanding over 50% market share. For facilities managers, system integrators, and maintenance teams, choosing between them is one of the most consequential automation decisions. This guide compares the two platforms across programming, hardware, pricing, and availability — with actionable recommendations based on your specific needs.
Quick Comparison Table
| Factor | Siemens (TIA Portal) | Allen-Bradley (Studio 5000) |
|---|---|---|
| Entry-level PLC | S7-1200 | CompactLogix 5069 |
| High-end PLC | S7-1500 | ControlLogix 1756 |
| Programming Language | LAD, FBD, SCL, STL, Graph | Ladder, FBD, Structured Text, SFC |
| IDE | TIA Portal (unified) | Studio 5000 Logix Designer |
| Safety PLC | S7-1500F (SIL 3) | GuardLogix 1756 (SIL 3) |
| Entry Price (CPU) | $200–500 | $500–1,500 |
| Market Share (Global) | ~30% | ~25% |
Programming: TIA Portal vs Studio 5000
Siemens TIA Portal offers a unified engineering framework — one software for PLC, HMI, drives, and SCADA. This integration saves engineering time when deploying multi-device systems. Studio 5000, while PLC-focused, provides deeper integration with Rockwell's FactoryTalk suite for visualization and data collection.
European-trained engineers typically prefer Siemens; North American teams favor Allen-Bradley. If your maintenance staff is already trained on one platform, switching costs can outweigh hardware savings.
Hardware: Expandability and I/O
The S7-1500 series offers hot-swappable I/O modules, integrated motion control, and native PROFINET support. ControlLogix provides ControlBus backplane at 100 Mbps and seamless integration with POINT I/O and FLEX I/O distributed systems. Both support thousands of I/O points, but Allen-Bradley's DeviceNet and EtherNet/IP ecosystem gives it an edge in brownfield North American installations.
Availability and Sourcing
Both brands face supply chain challenges for certain model lines. S7-300 and S7-400 are in "Active Mature" status — still available but with lead times stretching to 12+ weeks. For ControlLogix, 1756-L7 series processors are being replaced by L8 series, creating a surge in demand for L7 spares. Browse our PLC inventory →
Verdict
Choose Siemens if: You are in Europe/Asia, need integrated motion control, or want lower CPU cost.
Choose Allen-Bradley if: You are in North America, have existing DeviceNet infrastructure, or need ControlBus performance.
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