though...after restart controller....this message occurs "safe device communication error Profinet Device" 15002
but if I restart plc switching off/on 24 V power....communication with KRC4 is back and error is removed.
The solution I found it for this error:
When KRC4 starts, it takes almost 4-5 minutes until is initialized. If PLC is turned on once with KRC4, the PLC is much faster initialized than KRC4 and send communication signal too fast, controller being in initialization and not ready to receive signal. Thus, PLC cannot establishes network link with KRC4 and , message error communication Profinet device occurs.
That means PLC should start after KRC4 was initialized already. My solution was to add a timer relay that delay with 4 min. PLC powering with 24 VDC . When PLC start , so KRC4 is already started too and no error in communication happens. So it works for me.
Maybe it could be possible also from TIA portal using a start up delay with TON safety instruction block to realize similar effect, but didn't try.