Siemens vs Rockwell vs CODESYS: A Complete PLC Brands Comparison Guide
When selecting a PLC platform, consider not just the initial hardware and software costs, but also the total cost of ownership including training, maintenance, spare parts availability, and vendor support in your geographic region. A platform that appears cheaper upfront may incur significant hidden costs over the equipment’s 15-20 year operational lifespan.
Siemens PLC Platform Overview
Siemens AG dominates the European and global PLC market with their comprehensive S7 family of programmable controllers and the TIA Portal (Totally Integrated Automation Portal) development environment. The S7 series spans from compact micro-PLCs like the S7-1200 for basic applications to the high-performance S7-1500 for complex, mission-critical systems. Siemens’ strength lies in their deeply integrated ecosystem where hardware, software, and communication protocols are designed to work seamlessly together, providing exceptional diagnostic capabilities and engineering efficiency for large-scale automation projects.
The TIA Portal represents Siemens’ unified engineering framework, combining PLC programming, HMI design, drive configuration, and safety programming into a single environment. This integration significantly reduces engineering time and eliminates the friction points that occur when managing multiple disconnected software tools. Siemens utilizes PROFINET as their primary industrial Ethernet protocol, offering real-time communication with extensive diagnostic features and seamless integration with their industrial networks and field devices.
Rockwell Automation (Allen-Bradley) Platform Overview
Rockwell Automation and their iconic Allen-Bradley brand hold a dominant market position in North America, particularly in automotive, food and beverage, and oil and gas industries. Their PLC portfolio centers around the ControlLogix and CompactLogix families, programmed through Studio 5000 (formerly RSLogix 5000). Rockwell’s platform is renowned for its robust performance, extensive library of pre-engineered application code, and strong presence in process industries where reliability and vendor support are paramount concerns.
Studio 5000 provides a comprehensive development environment that has evolved significantly over decades of industrial deployment. The platform excels in large-scale discrete and process control applications, offering sophisticated motion control capabilities and extensive safety integration. Rockwell’s EtherNet/IP protocol has become an industry standard, providing open industrial networking that integrates well with third-party devices while maintaining deep integration within the Rockwell ecosystem. The company’s extensive network of distributors and system integrators ensures strong regional support across most industrial markets worldwide.
CODESYS Platform Overview
CODESYS represents a fundamentally different approach to industrial automation, functioning as a manufacturer-independent software platform that runs on PLC hardware from over 300 different manufacturers worldwide. Developed by Smart Software Solutions (3S-Smart Software Solutions GmbH), CODESYS provides a standardized development environment based on the IEC 61131-3 international standard, supporting all five programming languages defined in that specification within a single project. This independence gives users extraordinary flexibility to select hardware based on performance, price, or specific application requirements without being locked into a single manufacturer’s ecosystem.
The CODESYS Development System serves as the universal programming environment, offering powerful features including comprehensive debugging tools, version control integration, and extensive library support. Because the same software can program hardware from dozens of manufacturers, engineers can more easily standardize on a single development approach across diverse equipment fleets or switch hardware suppliers without retraining personnel. This platform particularly appeals to machine builders who may use different hardware for different customer requirements while maintaining consistent programming practices and code reusability across their product line.
Comprehensive Feature Comparison
| Feature Category | Siemens (TIA Portal) | Rockwell (Studio 5000) | CODESYS |
|---|---|---|---|
| Programming Languages | LAD, FBD, STL, SCL, GRAPH | LAD, FBD, ST, SFC | LAD, FBD, ST, IL, SFC, CFC |
| Primary Communication | PROFINET, PROFIBUS | EtherNet/IP, DeviceNet | Manufacturer-specific (EtherNet/IP, PROFINET, CANopen, etc.) |
| Software Licensing Cost | $$$$ (TIA Portal Professional) | $$$$ (Studio 5000 Architect) | $$ (Runtime-based licensing) |
| Learning Curve | Moderate to High | Moderate to High | Low to Moderate |
| Hardware Ecosystem | Proprietary Siemens hardware only | Proprietary Allen-Bradley hardware | 300+ manufacturers worldwide |
| Simulation Capability | Excellent integrated simulation | Good with Emulate software | Excellent built-in simulation |
| Motion Control Integration | Excellent (SINAMICS integration) | Excellent (Kinetix integration) | Good (manufacturer-dependent) |
Programming Philosophy and User Experience
The three platforms approach PLC programming with distinctly different philosophies that significantly impact developer productivity and code maintainability. Siemens TIA Portal emphasizes graphical configuration and automatic device recognition, allowing engineers to drag-and-drop hardware from an online catalog and have the system automatically configure parameters and addresses. This wizard-driven approach accelerates initial development but can create complexity when debugging or troubleshooting unfamiliar configurations.
Rockwell Studio 5000 takes a more traditional tag-based approach with highly structured program organization using routines, programs, and projects. The platform’s tag-based addressing system provides exceptional flexibility for large-scale applications, though the relationship between controller tags, program tags, and alias tags can confuse newcomers. Rockwell’s extensive use of add-on instructions and pre-engineered code libraries enables rapid development of standard functionality while promoting code consistency across large engineering teams.
CODESYS adheres most closely to the IEC 61131-3 standard, providing a clean, standardized development environment that translates well across different manufacturers’ hardware. The platform’s support for all five IEC languages within the same project encourages developers to select the most appropriate language for each specific task—using structured text for complex calculations, ladder logic for discrete control, and function block diagrams for continuous processes. This flexibility makes CODESYS particularly attractive for training and educational applications where students need to understand industrial programming fundamentals rather than manufacturer-specific nuances.
Cost Analysis and Economic Considerations
Total cost of ownership for PLC platforms extends far beyond initial hardware purchase prices, encompassing software licensing, training investments, maintenance requirements, and long-term support availability. The following analysis breaks down the major cost components to consider during platform selection:
Software Licensing Models
- Siemens TIA Portal: Uses a subscription-based licensing model with tiered options. The Professional license provides unlimited project capacity but carries significant annual costs. Basic licenses limit project scope and are suitable only for smaller applications. Floating licenses for team environments add additional expense.
- Rockwell Studio 5000: Requires perpetual licenses with annual maintenance fees for updates and technical support. The Total Economic Impact can be substantial for organizations requiring multiple engineering seats and extensive Add-On Profile libraries.
- CODESYS: Operates on a runtime-based model where the development environment is free for downloading but runtime licenses on the target hardware generate costs. This approach significantly reduces upfront investment while aligning ongoing costs with hardware deployment quantity.
Training and Workforce Development
- Siemens training is available through Siemens Digital Industries and certified training partners, with courses ranging from basic S7 programming to advanced motion control and safety integration. Training costs are substantial but the investment yields skills directly applicable to one of the market’s most widely deployed platforms.
- Rockwell training is offered through Rockwell’s Technical Education program and the extensive network of authorized training centers. The depth of curriculum matches Siemens with similar investment requirements for comprehensive certification.
- CODESYS training benefits from the platform’s standardized approach—skills developed on one manufacturer’s hardware transfer directly to another. This reduces training redundancy costs for organizations working with diverse equipment or global operations with varying hardware standards.
Industry Applications and Use Case Recommendations
Each platform excels in specific industrial contexts, and understanding these strengths helps guide platform selection for particular applications. The following recommendations synthesize practical experience across multiple industry verticals:
