Choosing between the Siemens S7-1500 and S7-1200 is one of the most common decisions automation engineers face when specifying a new control system. Both are programmed in TIA Portal and share many features, but they are designed for different scales of application.
Siemens S7-1200: The Compact Workhorse
The S7-1200 is Siemens' compact controller designed for small to medium automation tasks. It replaced the older S7-200 series and offers excellent value for money.
Key specifications:
- Processing speed: Up to 85 ns per Boolean operation
- Programme memory: Up to 150 KB (depending on CPU model)
- I/O capacity: Up to 284 digital I/O and 51 analogue I/O with expansion modules
- Communication: Integrated PROFINET port, supports up to 16 PROFINET devices
- Motion control: Up to 4 axes of motion control with PTO/PWM outputs
- Web server: Built-in web server for remote diagnostics
Ideal applications: Small machines, conveyor systems, packaging equipment, HVAC control, water treatment substations, and standalone equipment.
Siemens S7-1500: The Performance Leader
The S7-1500 is Siemens' high-performance controller for demanding automation tasks. It offers significantly more processing power, memory, and advanced features.
Key specifications:
- Processing speed: Up to 1 ns per Boolean operation (S7-1518)
- Programme memory: Up to 10 MB (depending on CPU model)
- I/O capacity: Virtually unlimited with distributed I/O via PROFINET
- Communication: Multiple PROFINET interfaces, PROFIBUS, and dedicated communication modules
- Motion control: Up to 128 axes with Technology Objects
- Safety: Fail-safe CPUs (S7-1516F, S7-1518F) for SIL 3 / PL e safety applications
- Display: Integrated front panel display for diagnostics without a laptop
Ideal applications: Large production lines, process automation, complex motion control, safety-critical systems, multi-station machines, and facility-wide control.
Feature Comparison
| Feature | S7-1200 | S7-1500 | |---------|---------|---------| | Price | Lower | Higher | | Performance | Good | Excellent | | Safety CPU | Not available | Available (F-CPUs) | | OPC UA server | Basic | Full featured | | Technology objects | Basic | Advanced | | Trace function | Limited | Full | | Security | Basic | Enhanced with access levels |
When to Choose S7-1200
Select the S7-1200 when your application has moderate I/O requirements, does not require integrated safety, and the budget is a primary concern. It is an excellent choice for OEM machine builders who need a reliable, cost-effective controller.
When to Choose S7-1500
Select the S7-1500 when your project demands high performance, integrated safety, advanced motion control, or extensive communication capabilities. It is the standard choice for system integrators working on large-scale industrial projects in the UK.
Learn Both at EDWartens UK
Our PLC training programmes at EDWartens UK cover both S7-1200 and S7-1500 platforms. Students gain hands-on experience with real hardware, learning the practical differences that influence project decisions in the real world.