Faced with the dazzling array of PLC brands in the market (Mitsubishi, Siemens, Omron…), how should beginners choose? Today, using real factory cases for comparison, I will teach you the 3 steps to select the most suitable PLC!
1. Core Differences Among Mainstream Brands
|
Brand |
Features |
Typical User Profile |
Representative Models |
|
Mitsubishi |
Japanese representative, strong stability, simple programming |
Electricians, automation equipment manufacturers |
FX3U (small), Q series (medium to large) |
|
Siemens |
German precision, powerful functions, complete ecosystem |
Automotive factories, high-end equipment companies |
S7-200 SMART (small), S7-1200 (medium) |
|
Omron |
High cost-performance ratio, rich Japanese-style instructions |
Small machinery factories, university laboratories |
CP1E (micro), NJ series (high-end) |
|
Schneider |
European brand, good compatibility |
Energy industry, rail transportation |
M241 (economical), Modicon M580 (high-end) |
|
AB |
American representative, suitable for complex systems |
Large factories, aerospace |
Micro800 (small), ControlLogix (large) |
2. Key Parameters Determine Selection Direction
1. Number of IO Points
Small PLC: <256 points (suitable for single machine control, such as vending machines)
Medium PLC: 256~1024 points (suitable for production lines, such as automotive welding lines)
Large PLC: >1024 points (suitable for plant-wide control, such as chemical DCS systems)
Beginner’s Pitfall: Choosing too small is insufficient, choosing too large wastes budget
Solution: Reserve 1.5 times the actual demand for expansion space
2. Programming Language Support
|
Language |
Mitsubishi Support |
Siemens Support |
Omron Support |
|
LD |
✅ |
✅ |
✅ |
|
SFC |
✅ |
✅ (SCL) |
✅ |
|
Structured Text |
❌ |
✅ (SCL) |
✅ |
Recommendation: Prioritize selecting PLCs that support LD (90% of electricians can directly use it)
3. Communication Capability
Basic Requirement: RS485/Modbus (connect to inverters, instruments)
Advanced Requirement: Ethernet/IP, Profibus (connect to robots, upper computers)
Case Study: A food factory needs to connect weighing sensors (Modbus) and MES systems (Ethernet), so they chose a PLC with dual communication ports
3 Major Series Comparisons Every Beginner Should See
1. Mitsubishi FX3U vs Siemens S7-200 SMART
|
Comparison Item |
FX3U |
S7-200 SMART |
|
Price |
About 1500 RMB |
About 2000 RMB |
|
Max IO |
256 points (requires expansion) |
60 points base + expansion |
|
Programming Software |
GX Works2 (free) |
TIA Portal (requires license) |
|
Advantages |
Japanese instructions are closer to Asian habits |
Seamless integration with Siemens inverters |
|
Applicable Scenarios |
Small to medium devices (e.g., injection molding machines, packaging machines) |
Factories with existing Siemens equipment (e.g., textile factories) |
2. Omron CP1E vs Schneider M241
|
Comparison Item |
CP1E |
M241 |
|
Size |
Ultra-micro (suitable for tight spaces) |
Compact design |
|
Analog Quantity |
Built-in 2 channels AD/DA |
Requires expansion module |
|
Programming |
CX-Programmer (simple) |
SoMachine (powerful) |
|
Applicable Scenarios |
University laboratories, small projects (e.g., automatic door control) |
Projects requiring connection to third-party devices (e.g., communication with ABB robots) |
3. Mitsubishi Q Series vs Siemens S7-1500
|
Comparison Item |
Q Series |
S7-1500 |
|
Processing Speed |
0.034μs/instruction |
0.002μs/instruction |
|
Expansion Capability |
Supports 1000+ IO points |
Supports 65536 points |
|
Price |
Starting from about 8000 RMB |
Starting from about 12000 RMB |
|
Applicable Scenarios |
Automotive production lines, semiconductor equipment |
Large factories, rail transportation |
4. Pitfall Guide: 5 Common Mistakes for Beginners
1. Blindly Pursuing the “Latest Model”
– Case: A factory chose a newly released PLC, only to find no compatible expansion modules available
– Recommendation: Choose mature models that have been on the market for over 2 years (e.g., FX3U, S7-200 SMART)
2. Ignoring Programming Software Costs
– Siemens TIA Portal professional version license fee exceeds 100,000 RMB, use caution for small projects
– Alternative: Choose brands that support free programming software (Mitsubishi, Omron)
3. Underestimating Communication Compatibility
– Case: Chose a PLC that does not support Modbus, unable to connect to existing instruments
– Solution: Confirm the required communication protocols for the project in advance (e.g., Modbus RTU/ASCII)
4. Only Looking at Base Price Without Considering Expansion Costs
– A certain brand has a cheap base unit, but each analog module costs 2000 RMB
– Calculation Method: Base price + Module price × Quantity needed
5. Choosing the Wrong Programming Language
– Case: Chose a PLC that only supports ST language, resulting in the electrician team being unable to maintain it
– Principle: Prioritize selecting PLCs that support LD (unless the team has an IT background)
5. 3 Steps to Select the Most Suitable PLC
Step 1: Clarify Project Requirements
Control Objects: Number of motors? Types of sensors?
Complexity: Is PID control needed? Multi-axis linkage?
Expandability: Will additional devices be needed in the next 3 years?
Step 2: Filter by Budget
Small Projects (<10,000 RMB): FX3U, CP1E, M241
Medium Projects (10,000-50,000 RMB): S7-1200, Q series basic model
Large Projects (>50,000 RMB): S7-1500, AB ControlLogix
Step 3: Verify Feasibility
Download the official manual to confirm if the required functions are supported
Search forums for “brand + model + issue” (e.g., “FX3U PID debugging experience”)
Consult suppliers to see if they can provide technical support
6. Summary: Best Choices for Different Scenarios
✅ Beginner Entry: Mitsubishi FX3U (plenty of resources, easy to use)
✅ University Laboratories: Omron CP1E (high cost-performance ratio)
✅ Automotive Factories: Siemens S7-1200 (compatible with Siemens equipment)
✅ Wastewater Treatment: Schneider M241 (supports multiple communication protocols)
✅ High-end Manufacturing: Mitsubishi Q Series (high-speed processing + rich modules)
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What PLCs have you used in your projects? Which brand has been the most reliable for you? Share your experiences in the comments!