The S7-1200 and S7-1500 are the two current SIMATIC controller families. They look similar in TIA Portal but serve very different machine classes. This comparison gives you a decision table you can apply in minutes.
| Criterion | S7-1200 | S7-1500 |
|---|---|---|
| Target class | Compact / OEM machines | Mid to high-end machines and lines |
| Typical I/O count | Up to ~100 points | Several thousand points |
| Motion control | Basic (PLCopen blocks) | Technology objects, cam, kinematic |
| Communication | PROFINET, Modbus TCP | PROFINET IRT, PROFIBUS, OPC UA |
| Program memory | 2–4 MB | Up to 24 MB+ |
| Web server / diagnostics | Basic | Full trace, diagnostics buffers |
| Typical price band | Entry | 2–5× S7-1200 |
Your machine has fewer than about 100 I/O points, speed demands are modest, and you need PROFINET plus basic motion. Packaging machines, conveyors, HVAC skids and OEM modules are the classic S7-1200 territory — lowest cost per point and easiest maintenance.
You need multi-axis motion synchronization, large I/O counts, PROFINET IRT for drive synchronization, or extensive tracing. Production lines, presses and robotics cells belong on S7-1500. The higher CPU price pays back through reduced engineering effort and better diagnostics.
Both families are field-proven, and both age into the spare-parts market. If you are standardizing a fleet, S7-1200 signal modules (SM 1221/1222/1231/1232) and S7-1500 signal modules (SM 521/522/531/532) are both widely stocked — send us your MPN for a stock check.
No — they use different CPU architectures. Projects must be re-created for the target CPU in TIA Portal.
S7-1200 — lower hardware cost and simpler spares. S7-1500 wins on diagnostics uptime for complex lines.
Yes — the S7-1500 family (including the 1500R/H redundant and F variants) remains Siemens' mid-to-high-end SIMATIC platform.