My problem is solved!
Factory reset makes parameter 0051 0001 and this causes the problem. There is a way to return the value to 0000.
Serial port is still working, I could send a query and get response.
You can open serial port with terminal settings 9600bps 8N1.
and with this order.
This sequence solved my problem
- Start configuration mode
- Set paramater 0051 to 0000
- Save user parameters
- End configuration mode