Watch dog for AC450/800xA System.
Right - so "Safeguard" would be an important thing for you to say here.
Im quite sure there will be a heartbeat timer between the AC410 Safeguard and the AC450 somewhere. This will likely be a tag passed over a DataSet between the controllers. There will also be a PC Program on each end monitoring the changes to the tag. But it is likely to be application or site specific so you will need to look in your own AC410 and AC450 source code.
Any watchdog between the Advant controllers is quite independant of the 800xA operator stations and connectivity servers.