Hi,
I have a Siemens S7-1200 CPU that keeps going into STOP.
Errors shown:

• CPU STOP due to serious error
• OB122 missing
• Access error – periphery address not available

I don’t have the project or backup.
No idea what was programmed before – I took over after failure.
Is there any way to fix this or at least get it running again without the original code?

Appreciate any tips. Thanks.

6 of 50; Event ID: 16# 02:3956
Error: Hardware component not available due to a parameter assignment error 

HW_ID=   270

Incoming event
Event type:  Error
7/15/2025 12:31:39.897 PM
(Coding:  16#  20 01 00 03 18 52 66 21  B1 76 38 08 39 56 00 00  04 A1 00 00 00 00 01 0E  00 02 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  00 00 00 00)
 

Thanks for the advice. I tried uploading the program from the PLC but got an error message saying it was impossible. From what I checked, the project is in TIA v15, and I was trying to upload v16. Could that be the problem?

I will add that the input and output modules are safe modules.

Yes, you're right, there's no option to download it on the official website and Siemens support doesn't respond ;( . Thank you very much for your help.

So in this case, all that remains is to recover the program backup or write a new program?

artur_163

So in this case, all that remains is to recover the program backup or write a new program?

 You can still do diagnostics online, even if you don't have the engineering copy of the project.