Hello,

rigth the Problem is not clear!

Which S7-1200 with which FW Version?
Which TIA Version?
How you connected(wired) from PC to S7-1200.

Have the PC Networkcard a IP in hte Range of the S7-1200 IP?
Can you ping the S7-1200?

Regards

Christoph

The CPU 1200 firmware is V3.
TIA Portal V13.
I can't PING the CPU.

BUT BEFORE, i use software and hardware with normal condition, upload and download normal, normal IO test, the last i try to program stepper motor is normal too. But suddenly problematic as mentioned above.

this problem is suddenly.
Could the PLC be broken?

Hello,

how about LEDs on CPU?

I suggest to do a complete reset of the PLC. try to come online with the PLC and then reset it including IP adres.

after some time try to load it again.

by the way, the PLC does not have to have the same subnet as your programming device, as long it is on the same router, they should find eachother, and then tia makes an extra IP adres on your computer, so it can communicate with the PLC

Naaltje.

i was read, this problem is LED test or defective CPU firmware. (pages 674 of system manual)

I can not go online anymore, but before I can.

Hi

You could try the Simatic Automation Tool, perhaps it's possible to see the CPU and reset it to Factory settings

If you have a Simatic Memory Card try transfering the Project to the PLC using the Card

Link to  Simatic Automation Tool