Why Genuine Siemens Parts Matter
When a Siemens drive, PLC, or appliance component fails, the temptation to save money with a cheaper third-party or unverified online part is understandable. However, counterfeit or incompatible components can cause further damage, void warranties, create safety hazards, and — in industrial settings — lead to production losses that far outweigh the initial saving. Understanding how to source the right part is one of the most valuable skills for any maintenance professional.
Understanding Siemens Part Numbers (MLFB)
Siemens uses a structured ordering number system called MLFB (Maschinenlesbare Fabrikatbezeichnung — machine-readable product designation). Every Siemens product has a unique MLFB that encodes key specifications such as voltage rating, current rating, and variant.
Where to Find the MLFB
- Product nameplate: Always affixed to the device — check the side or back panel
- Original documentation: Delivery notes, commissioning reports, and BOM records
- TIA Portal / STEP 7: The hardware configuration shows the MLFB of every configured module
- Siemens Industry Mall: Search by product family and specification to find the correct MLFB
How to Verify a Genuine Siemens Product
Siemens provides a free online tool — the Siemens Product Authenticity Check — that allows you to verify whether a product is genuine using the serial number printed on the product label. Always use this before installing any component sourced from a non-authorised channel.
Visual Inspection Tips
- The Siemens logo should be crisp and consistent — fuzzy printing or misaligned logos are warning signs
- Check that the product label includes a serial number, MLFB, manufacturing date code, and CE marking
- Genuine Siemens products have consistent, high-quality enclosure moulding with no rough edges or misaligned seams
- Connector pins and terminals should be clean, uniformly plated, and free from corrosion or burrs
- Counterfeit parts often have incorrect or missing safety markings (UL, CE, TÜV)
Authorised Siemens Spare Parts Channels
| Channel | Best For | Notes |
|---|---|---|
| Siemens Industry Mall (mall.industry.siemens.com) | Direct purchase, guaranteed genuine | International shipping; lead times vary |
| Authorised Siemens distributors | Local stock, technical support | Check Siemens partner finder for local authorised dealers |
| Siemens service centres | Repairs, refurbished spares, warranty support | Ideal for complex assemblies and PCB-level repairs |
| Siemens Digital Industries Service | Emergency spares, on-site support | Suitable for critical infrastructure applications |
New vs. Refurbished vs. Upgraded Parts
When a component is discontinued or has a very long lead time, you may need to consider alternatives:
Siemens Certified Refurbished
Siemens offers a certified refurbishment programme for certain product lines. These units are tested, repaired to original specification, and carry a warranty. This is a legitimate and cost-effective option for legacy S5 or older S7 hardware.
Third-Party Refurbished
Exercise caution. Only use reputable, ISO-certified repair centres with documented test procedures. Ask for test reports and a back-to-back warranty. Avoid untested units sold "as-is".
Functional Upgrades
If you are replacing an end-of-life component, consider whether upgrading to a current-generation equivalent makes sense. For example, migrating from an older S7-300 CPU to a S7-1500 may cost more upfront but offers better performance, longer future support, and simpler spare parts management.
Keeping a Spares Inventory
For critical systems, maintaining a small stock of high-wear or long-lead-time spares on site is good practice. Candidates for an on-site spares kit include:
- Cooling fans for drives and large CPUs
- Fuses (correct rating and type)
- SIMATIC Memory Cards
- Battery modules for CPUs with real-time clocks
- One spare I/O module of each type deployed