Siemens vs Schneider vs ABB: How to Choose

Choosing between Siemens, Schneider Electric, and ABB for your industrial automation platform is a strategic decision that affects your plant’s efficiency, maintenance costs, and long-term scalability. This guide breaks down the key technical, commercial, and practical factors to consider, helping you match each vendor’s strengths to your specific application requirements.

What You’ll Need

• Your application’s I/O count (digital and analog inputs/outputs)
• Communication protocol requirements (PROFINET, EtherNet/IP, Modbus, etc.)
• Number of axes/motion control needs, if any
• Safety integrity level (SIL) or performance level (PL) required
• Existing installed base in your facility (if any)
• Budget range for hardware and engineering software licenses
• In-house engineering skill set and training availability

Step-by-Step

1. List your automation requirements. Start by writing down your process’s exact needs: number of I/O points, type of control (discrete, process, motion), network topology, and any functional safety requirements. This list will serve as your evaluation scorecard.
2. Check your existing installed base. If your plant already runs Siemens S7 controllers, Schneider Modicon, or ABB AC500, staying with the same vendor reduces training costs and simplifies spare parts inventory. If you’re starting greenfield, you have more freedom.
3. Compare programming environments. Siemens uses TIA Portal (with Step 7), Schneider uses EcoStruxure Control Expert (formerly Unity Pro), and ABB uses Automation Builder with CODESYS. If your engineers are already certified in one, that’s a significant advantage. If not, evaluate which environment feels more intuitive for your team.
4. Evaluate communication protocol support. All three support common industrial protocols, but there are differences. Siemens is native to PROFINET and PROFIBUS; Schneider supports Modbus TCP/RTU and EtherNet/IP; ABB supports PROFINET, EtherNet/IP, and Modbus TCP. Ensure the chosen platform integrates with your existing drives, sensors, and SCADA.
5. Assess motion control capabilities. If your application involves multi-axis servo control, compare the motion controllers and drive families. Siemens (Sinamics) and ABB (ACS, MotiFlex) have strong motion portfolios; Schneider’s offering is competent but less dominant in high-axis-count applications.
6. Review functional safety options. For safety-rated applications, check the safety PLCs and certified safety communication. Siemens offers F-CPUs, Schneider offers Safety PLCs, and ABB has SafePLC. Verify the SIL rating and that the safety engineering is integrated into the same programming environment.
7. Compare scalability and future-proofing. Look at the range from micro-PLCs to high-end process controllers. Siemens S7-1200 to S7-1500, Schneider M221 to M580, ABB AC500 to AC500-S. Ensure the platform can grow with your plant without a complete rewrite.
8. Estimate total cost of ownership. Beyond initial hardware, consider software licenses (which can be costly), spare parts, training, and support contracts. Get quotes for a typical project and compare.
9. Check local support and delivery times. Contact local distributors or system integrators. Ask about stock availability, technical support response times, and the availability of engineers with that vendor’s certification.
10. Run a proof-of-concept. If possible, build a small test rig with each PLC and simulate your process. This is the most reliable way to see which platform fits your team’s workflow and meets performance expectations.

Common Mistakes

• Ignoring the software ecosystem. Many buyers focus on hardware price, but engineering software licenses and maintenance fees can outweigh hardware costs over a project’s lifetime.
• Overlooking backward compatibility. If you have legacy equipment, ensure the new platform can communicate with it via gateways or protocol converters. Don’t assume all three support legacy protocols equally.
• Choosing based on a single feature. A vendor might excel in motion control, but if your application is mostly process control, that advantage may be irrelevant.
• Not considering cybersecurity features. All three offer security features, but the depth of integration and ease of configuring security settings varies. Check for built-in firewall, certificate management, and secure remote access.
• Assuming all PLCs are the same. Each vendor has different scan times, memory, and communication buffers. Verify that the chosen model meets your real-time requirements.

Tips

• Use the vendor’s configuration tools to simulate your I/O layout and network load before committing.
• Ask for reference installations in your industry. A vendor with strong experience in your sector (e.g., automotive, water treatment) is often a safer bet.
• Consider the availability of spare parts. For critical processes, having a local stock of modules can be more important than the list price.
• Check if the vendor offers a free or low-cost training environment (like simulation software) so your team can practice before the hardware arrives.
• Look at the vendor’s roadmap. If they are migrating to a new platform, ensure your chosen series will be supported for at least 10 years.

Troubleshooting

If you’re stuck between two vendors: Create a weighted decision matrix. List your top 5 criteria (e.g., cost, support, protocol support, safety, scalability) and assign weights. Score each vendor on a 1-5 scale. The highest total wins. This removes emotional bias.

If your team already knows one vendor but the other is cheaper: Calculate the cost of retraining. If the savings are less than the training cost (including lost productivity), it’s often better to stick with the known platform.

If you’re worried about vendor lock-in: Focus on open protocols like OPC UA and MQTT. All three support these, so you can integrate with other systems regardless of PLC brand. Choose a PLC that supports these standards.

If you can’t decide on motion control: Ask for a benchmark test with your actual servo motors. Some vendors have better tuning algorithms that can reduce cycle times.

If the project is time-critical: Check lead times for the specific PLC models. Sometimes one vendor has a shorter lead time for the exact configuration you need.

Frequently Asked Questions

Q: Which platform is best for a small machine builder?
A: For small machines, ABB’s AC500 with CODESYS is often cost-effective and flexible. Siemens S7-1200 is also popular but may have higher software licensing costs.

Q: Do all three support PROFINET?
A: Yes, all three support PROFINET, but Siemens has the most mature implementation and is the standard-bearer for this protocol. Schneider and ABB also support PROFINET, but you may need to check specific model variants.

Q: Which platform is best for process industries like oil and gas?
A: Schneider Electric’s Triconex and Modicon M580 are strong in process safety and redundancy. Siemens S7-400/1500 with F-option is also widely used. ABB’s AC500 is less common in large process plants.

Q: Is it easy to migrate from one vendor to another?
A: Migration is possible but not trivial. You’ll need to rewrite the logic in the new programming environment, and you may need to change HMI/SCADA tags. Plan for a significant engineering effort.

Q: Which platform has the best built-in cybersecurity?
A: All three offer security features, but Siemens has a comprehensive defense-in-depth approach with TIA Portal security integrated. Schneider and ABB also provide robust options, but the ease of implementation varies.

Q: Can I mix PLCs from different vendors in one plant?
A: Yes, using OPC UA or MQTT for data exchange. However, this adds integration complexity. For a single line, it’s usually simpler to stick with one vendor.

Related

• Future Proofing Tech: Why It’s Pointless
• Disk Space Is Used: What It Means & How to Fix It
• Why Streaming Subtitles Are Always Slightly Wrong