SIMATIC S7-300 end of life: how to plan the move to S7-1500
Many plants still run on S7-300 controllers. Siemens has set an end date, and spare parts are getting scarcer and more expensive. This is how we plan a migration so production keeps running.
Siemens states that the SIMATIC S7-300 and ET 200M families entered phase-out on 1 October 2023, have been supplied only as spare parts since 1 October 2025, and can no longer be ordered from 1 October 2033. Plan the move to S7-1500 now: take inventory, rank by risk and migrate in steps.
What has changed
| Date | Status | What it means |
|---|---|---|
| 1 October 2023 | Phase-out starts | Siemens starts the phase-out of the S7-300 and ET 200M families |
| 1 October 2025 | Spare parts only | No longer sold as new products; supplied only as replacements |
| 1 October 2033 | End of orders | S7-300 and ET 200M products can no longer be ordered |
Siemens recommends SIMATIC S7-1500 or S7-1200 controllers with ET 200SP I/O and TIA Portal; ET 200MP is the other common I/O choice with S7-1500. Check the status of each order number in Siemens Industry Online Support.
Plan the migration in five steps
- Inventory. List every S7-300 CPU, I/O module and network part with its order number, and check its lifecycle status.
- Rank by risk. Which lines stop the plant if a CPU fails? Where are spares already missing? Start there.
- Choose the approach. Replace everything in one shutdown, or step by step. A common intermediate step: install an S7-1500 CPU first and keep the ET 200M I/O racks for now, connected over PROFINET with a PROFINET interface module, then replace the I/O later. ET 200M is also in discontinuation, so this buys time but is not the end state.
- Convert and test. Migrate the STEP 7 program to TIA Portal, bring it to your standard, and test it in S7-PLCSIM Advanced against the real HMI or SCADA before the shutdown.
- Cut over. Switch in a planned window with the old CPU and program ready as a fallback, then run the loop checks and the handover.
Do not forget HMI and SCADA
A PLC change often affects the HMI and SCADA too: tag addresses, communication drivers and alarm configuration. Plan the HMI and SCADA side together with the PLC, or use the moment to move an old WinCC system to a newer platform. See legacy PLC and SCADA migration.
Where AI speeds this up
Old S7 programs are often poorly documented. Our Engineering Assistant reads the existing program, documents what each block does, finds where tags are used, and helps convert and clean up the code in TIA Portal. An engineer reviews and tests every block before it goes near the plant.
Questions we get
Can we keep running S7-300 until 2033?
You can, but spare parts are limited and expected to get more expensive, and extensions are no longer possible. The risk grows every year, especially for lines without a spare CPU.
Can TIA Portal open our STEP 7 projects?
TIA Portal can migrate STEP 7 V5.x projects, but the result needs engineering work: hardware changes, instructions that behave differently, and cleaning up to your standard.
How long does a migration take?
It depends on the size of the program, the I/O count and the impact on HMI and SCADA. The inventory in step 1 gives a clear picture, and we base the plan and price on it.
Sources
A new line, an upgrade, or AI for your plant?
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