SIMATIC S7-300 end of life: spares, repair or migrate

The SIMATIC S7-300 is in its end-of-life phase. Siemens announced the product phase-out of the S7-300 and the ET 200M I/O system on 1 October 2023 (milestone PM400), and type discontinuation (PM410) took effect on 1 October 2025. Since then, Siemens supplies these components only as spare parts or through repair. The system still runs, and parts are still available — but the time to plan what comes next is now.

This guide explains what each Siemens milestone means, what you can still get for an S7-300 or ET 200M installation, and how to decide between keeping it running on spares and migrating. Everything about dates and policy below comes from Siemens’ own product note, entry 109809890 in Siemens Industry Online Support.

The S7-300 phase-out timeline

Siemens uses fixed milestones for a product’s end of life. For the S7-300 and ET 200M they are:

• PM400 — product phase-out announcement: 1 October 2023. Until this date the components were available as new parts without restriction. From it, they were removed from active marketing and no longer listed in the catalog.
• PM410 — type discontinuation: 1 October 2025. Until this date the components were still sold as new parts. From it, they are available only as spare parts or can be returned for repair.
• PM490 — discontinuation: not yet set. From PM490 the components can no longer be ordered, and only warranty cases are handled.

Siemens says PM490 is not planned before a ten-year period after PM400 has passed. It also says it cannot guarantee this for every module, because of the component market, and that individual components may be withdrawn earlier. So the ten-year period is a plan, not a promise for a specific part.

The phase-out covers the whole system: S7-300 CPUs, I/O, communication and function modules, accessories, the ET 200M interface modules and the SIPLUS versions for extended ambient conditions.

What “spare parts only” means in practice

Since PM410 you can still get S7-300 and ET 200M components from Siemens, but on spare-part terms. Siemens lists the limits in its product note:

• Components can be bought only in quantities that are customary for spare parts.
• Plant expansions and new projects can no longer be built on them.
• Siemens reserves the right to deliver some components only in exchange for the defective part.
• Siemens reserves the right to charge for service requests on these products in the future.

For a running machine this is usually enough: a failed module can be replaced or repaired. What changes is planning. If you were counting on adding stations or building a copy of an existing line on S7-300, Siemens recommends switching to a successor system now.

Find your modules in Siemens’ phase-out tables

Siemens publishes overview tables with the planned discontinuation date of each S7-300 and ET 200M component and a reference to its successor product. The Factory Automation table has separate sheets for S7-300 CPUs, S7-300 I/O, S7-300 accessories, ET 200M and SIPLUS. There is a second table for migrating ET 200M to ET 200SP, and a Process Automation table for ET 200SP HA.

The tables are searched by the individual article number (Siemens calls it the MLFB) — bundles are not listed. Read the article number from the label on each module in your rack; our guide on how to find your part number shows where to look. For each module, the table gives two kinds of replacement:

• Recommended product — the most appropriate functionally suitable successor.
• Alternative product — a functional alternative. It may offer more, such as extra parameters or diagnostics, and in some special cases it covers only part of the original’s function.

Siemens adds that you should check the technical features and the intended use of each successor yourself. A table entry is a starting point, not a drop-in guarantee.

Keep running on spares, or migrate?

There is no single answer, and Siemens’ note does not give one for existing installations. These questions help you decide:

• Is the machine staying as it is? A stable line that only needs replacements when something fails can usually keep going on spare and repaired modules.
• Will it grow? Expansions are exactly what Siemens says spare-part supply no longer covers. If you plan to add I/O or stations, plan the migration with them.
• Which modules does it depend on? Check the planned dates of your specific article numbers in the tables. One module with an early date can decide the timing for the whole rack.
• How long must the machine run? If it needs to run well beyond the planned PM490 period, holding spares only postpones the migration.

Many plants do both: they keep spare modules on the shelf for the existing S7-300 installation and plan the move to the successor system for a scheduled shutdown, instead of during a breakdown.

The successor systems and migration tools

Siemens names these functional replacements for S7-300 and ET 200M:

• Factory automation: the S7-1500 controller with the ET 200MP I/O system.
• ET 200M remote I/O in manufacturing: ET 200SP is also possible. Siemens recommends it especially for applications with redundant interface modules without PCS 7, for example in tunnels, water and wastewater, or data centers.
• Process automation: the S7-400 controller with the ET 200SP HA I/O system.

To plan the change, Siemens points to its free TIA Selection Tool, available as a desktop download or in the cloud. It helps you choose modules and accessories, plan an initial network and power supply, and produce an order list. Siemens also refers questions about a migration to your local Siemens sales representative.

Finding S7-300 and ET 200M spares

Spare-part supply from Siemens is one route. Unused and used modules from the second-hand market are another, and for many installations they are how a machine stays running between planned shutdowns. If you go that way:

• Match the full article number on the label, not just the module type — two modules with the same name can have different numbers.
• Check the condition label and what it means for warranty and returns. Our condition guide explains each one.
• Look at the listing photos for the label and connectors, and ask if anything you need to know is missing.

We are not an authorized Siemens dealer, and we do not test parts. You can browse the Siemens parts we have in PLCs & Controllers and I/O & Communication Modules, or on the Siemens brand page. If the module you need is not listed, send us the article number through Request a Part.

Frequently asked questions

Sources

1. Siemens Industry Online Support — Information about the product phase-out of S7-300 / ET 200M components, product note, entry ID 109809890 (entry date 01/20/2026) (opens in a new tab)