Rik, in addition to what Ray posted, if you are able to use WiFi instead of the ethernet module, you may be able to avoid the crashes. My system has been running via WiFi for several days now without crashes. I *do* have a lot of issues with not being able to connect to the controller, but the controller isn’t actually crashing, and whatever is causing it to timeout while trying to connect eventually resolves itself without my intervention. It’s possible that my timeout issues are related to WiFi signal strength in my garage, so you may not even have to deal with this inconvenience in your setup.
Also, if your controller is connected to a switch that supports VLANs, you may be able to solve the problem without the hassle of setting up a secondary router as Ray outlined in #4 above. Another user reported that putting the controller on its own private VLAN solved the problem for him. I haven’t tried this yet myself because my controller is connected to a non-VLAN capable switch that’s downstream from my main switch that does support VLANs.