You didn't write about your OS, I suspect you are using a Windows, probably Windows 7. In this case, my answer is:
-
Theoretically, not. What you are hit, it is one of the most important problems of the OSes and Windows7 can solve that relatively easily. Different devices and their configuration / reconfiguration should be done independently.
-
Practically, yes, but not very badly. It is not clear, what is ruing on your PLC controller, but considering that you are controlling it from a windows, I am sure, it is not really critical. A little bit of delay could happen.
- There could be another danger, if your next system configuration causes some ueeded interaction between your network interfaces. For example, if your new IP is an IP on your PLC-side network. But it is in most cases some buggy configuration and I susepct you know what are you doing.