Siemens S7-400 lifecycle: which CPUs are EOL and what is the migration path?
Always verify current status via Siemens Product Lifecycle Management (PLM)
The lifecycle status of individual S7-400 CPU variants differs and is updated by Siemens. The table below gives the general direction. Consult the Siemens Industry Mall or product page for exact dates per article number.
The Siemens SIMATIC S7-400 has been the workhorse of heavy industry, chemicals, water treatment, and power plants for over 30 years. Unlike the S7-300, the S7-400 does not go EOL all at once. The phase-out is partial and per CPU family. The compact 412 and 414 series are already out of sale; the 416 and 417 series follow. H-redundant and F-versions (failsafe) remain available for now but Siemens is actively directing customers to the S7-1500H and S7-1500F. GCG supports S7-400 migrations including the more complex redundant and safety CPU tracks.
S7-400 CPU lifecycle overview
Indicative. Consult Siemens Industry Mall for exact dates per article number.
| CPU | Application | Status | Note |
|---|---|---|---|
| CPU 412-1 / 412-2 | Compact tasks, lower throughput | EOL | Sales discontinued |
| CPU 414-2 / 414-3 | Mid-size installations | EOL | Sales discontinued |
| CPU 416-2 / 416-3 | Large programs, high I/O density | Phase-out | Consult Siemens PLM |
| CPU 417-4 | Maximum performance, DCS coupling | Active | Lifecycle announced |
| CPU 412H / 417H (redundant) | High availability | Active | Long-term product |
| CPU 416F / 417F (failsafe) | Safety installations (SIL 2/3) | Active | Siemens pushes S7-1500F |
S7-400 vs S7-300: migration differences
Larger programs and memory
S7-400 CPUs have significantly more working memory (up to 16 MB) than S7-300. Large programs with complex process control, DCS coupling, and extensive diagnostics require an S7-1500 CPU with sufficient memory. A 1:1 CPU choice is not automatically correct.
UR rack vs S7-1500 profile rail
S7-400 uses UR1/UR2/UR2-H racks with backplane bus. S7-1500 uses its own TM (Terminal Module) profile rail. The mechanical layout of the control cabinet changes significantly. GCG designs a new cabinet layout as part of the migration.
H-redundancy (S7-400H → S7-1500H)
S7-400H redundant systems require a specific migration path to S7-1500H. The synchronisation link (fibre or copper bus) changes. Switchover tests and warm-switch verification are mandatory parts of the FAT/SAT. GCG has experience with H-system migration projects in the process industry.
F-systems (SIL 2/3): TÜV process required
S7-400F/FH safety functions are certified for SIL 2 or SIL 3. Migration to S7-1500F requires revalidation of Safety Instrumented Functions (SIF), an updated PHA/LOPA, and TÜV approval. This is a separate track with its own timeline alongside the standard PLC migration.
Migration path: S7-400 → S7-1500
The migration path from S7-400 to S7-1500 runs via TIA Portal Migration Tool (STEP 7 → TIA Portal) and is similar to the S7-300 track, but the higher complexity of S7-400 installations (large memory, redundancy, F-functions) requires a more careful engineering process.
PLC
S7-400 (412 / 414 / 416 / 417)
S7-1500 (1511 / 1515 / 1517)
Redundant
S7-400H
S7-1500H
Failsafe
S7-400F / S7-400FH
S7-1500F / S7-1500TF
Engineering
STEP 7 V5.x (Classic)
TIA Portal V18