SIMATIC S7-300
For legacy CPU and I/O replacements, check the complete 6ES7 reference, firmware, front-connector needs and module compatibility.
Ask us to source a part →SIEMENS / PLC AND INDUSTRIAL CONTROLS
Siemens spares. Sourced with care.
We help UK maintenance teams investigate hard-to-find Siemens SIMATIC CPUs, modules, operator panels and drive equipment. Availability is verified for each exact order number before quoting.
Product families
Equipment we investigate.
The original module label and exact part number are the starting point; supplier availability is confirmed only after enquiry.
SIMATIC S7-400
For larger rack-based systems, confirm the CPU order number, communications requirements, memory and any redundant or safety configuration.
Ask us to source a part →SIMATIC HMI
Panel size alone does not identify the replacement. Check the full 6AV reference, software project and available backup.
Ask us to source a part →SINAMICS & legacy drives
A similar power rating does not guarantee a drop-in replacement. Confirm the complete 6SL number and application configuration.
Ask us to source a part →Reference examples
Commonly searched part numbers.
Illustrative manufacturer references to help start an enquiry. These are not live stock listings.
CPU 315-2 DP example. Confirm exact suffix, firmware and programme backup before ordering.
Enquire about this part →CPU 416-3 PN/DP example. Identify memory, rack and communications requirements.
Enquire about this part →CPU 416-2 reference. Verify the original unit's complete code and version.
Enquire about this part →SINAMICS part-number example. Confirm rating, hardware version and installation details.
Enquire about this part →Availability transparency: A part number shown in this sourcing directory is a reference for enquiries, not a stock or price offer. AO checks each source, unit condition, quantity, delivery date and terms before making a quotation.
Engineering matters
Before you order a replacement
A correctly identified spare is worth far more than a visually similar module.
CHECK 01
Exact order number
Read the label, including every prefix and suffix. Where possible send a clear photo.
CHECK 02
Firmware & revision
Check compatibility with the existing PLC, HMI or drive project, accessories and communication method.
CHECK 03
Unit condition
Agree new, used or refurbished condition, warranty and available testing before committing.
Questions buyers ask
Siemens sourcing FAQ
A clear answer before you commit money to a discontinued spare.
Is an S7-300 replacement always plug-and-play?
No. Verify exact order number, firmware, programme, memory card and communications setup. Physical fit alone is insufficient.
Can you source Siemens drives as well as PLCs?
Yes, we can investigate identified SINAMICS and older drive order numbers. Sourcing depends on actual availability.
Are these Siemens parts shown as in stock?
No. These pages describe possible sourcing enquiries. Only current AO product listings offer specific units for purchase.
Quote request
Know your part number?
Send the full Siemens order code, quantity, required condition and location.
Free PLC fault-finding resources
Practical information first, with sourcing available if diagnostics confirm you need a replacement.
Troubleshooting
Siemens S7-300 SF / BF fault
Check LED indications, the diagnostic buffer and network evidence before replacing the CPU.
Read the diagnostic guide →Engineering knowledge
PLC fault guides
Free fault-finding information, a replacement checklist and engineering tools.
Browse the resource hub →