M580 Hot Standby automatic IP address swapping.
How is the M580 Hot Standby IP address swapping feature configured using Unity Pro?
Control Expert, Unity Pro, Modicon M580
The addressing swapping feature is not something that can be turned on and off. It is not configurable. When you have synchronized M580s both online, the Primary will have the Main IP and the Standby will have the Main IP +1. If the Primary fails, the formerly Standby will become Primary and inherit the Main IP address.