Is there an effective way to implement Ignition Edge as a backup “gateway”/project with limited controls in case of a network failure? How should the communications between PLC and gateways be set up? Is it better to have just the Edge gateway connected to the PLC and have it communicate with the main gateway(remote tag provider)* or to have Edge and Main both poll the PLC directly. If it is better for them to poll separately, is there a way so Edge only starts polling if the main is down, essentially having it function similarly to a regular backup gateway.
You could set the Edge Gateway as the Local Client Fallback gateway. Then for the device connection, you could enable or disable the device connection based on the value in the IsAvailable System tag in the Gateway Network system tags. That way the device is only enabled and polling when the GAN connection is down.