problem with module of S7-1200

Right click each unhappy module and select online & diagnostics.  They likely will report the module does not exist for all 3 of them.

Expand your project tree and scroll down to "Online Access" and expand that and find your PLC connected to the correct network adapter.

Check the online hardware configuration.  Upload the hardware configuration to a copy of your original project if you are not able to see all the hardware modules.

The end goal is to use the diagnostics buffer, spare project hardware upload, or any tool you know how to use that will show you the exact part # and firmware revision for 3 modules that appear unhappy in your project.

They are probably not correct in your project relative to the actual hardware.

Either that, or the slider is not fully engaged on the 1st unhappy module.

Billel11

Hello;

I encountered a problem with an automated S7-1200 system, the problem is as follows:

the last 3 modules were in default (image 01).

for the DI module the error is as it appears in the 2nd picture; knowing that I check the hardware configuration and I found no inconsistency, in addition the online serial number appears in the image is of the DO module that is after the DI and for the Module DO the same problem it has a discrepancy defect but the online serial number is of the AI that follows the DO, I tried to change the last 3 modules DI, DO, AI, I changed the power source of the CPU but the problem persists???