Hi everyone.

I have a s7 1200 plc cpu1214C dc/dc/dc

At last week , there is no problem. And I can connect to PLC and program it . 

But today, when I connect power 24VDC to it , the Error Led start to blinking (RUN led is green and ok ).

In TIA V17 , I can only see IP address of plc , and I can not assign New IP address. When I try to download program to It , the following error appear: 

"connection failed. Selected online target is not reached....." 

Can you belp me to solve this problem ?

(I have Windows 10 , 64bit)

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Split from S7 1200 CPU 1214C Error Led is Blinking.

Hi,

PC and S7-1200 have a fixed IP address and are on the same subnet? You can try using PRONETA to change the IP address of the S7-1200.

I would also not rule out trying to "Repair" the TIA Portal installation, from the Setup of the initial installation, just in case the S7DOS driver is damaged / corrupted.

Hi 

Thanks for your kindly reply.

My problem had been solve

Here I will say how ...

Because of my Windows Firewall, I can not connect to plc. 

So my colleague suggest to disable the fire wall . And now I can connect to plc easily.