Is it possible to have multiple local HMI’s running ignition that continue to operate with their local PLC’s after communication with the central gateway is lost? In the event of communication loss, we still want to be able to use local user kiosk for operation.
If this is possible, what system architecture needs to be used? Would I be able to use Perspective for HMI design?
This is only possible if each Local HMI has a connection to a gateway where the device connection is made. It would also mean that the project would need to be made on that same Gateway, so the Vision or Perspective Module would need to be installed there.
You will probably want to look into Ignition Edge. I believe this is the type of thing Edge was designed for.
Is it possible to use this in conjunction with regular ignition? The goal is for the end user to be able to access the local HMI’s at all times even when a connection is broken from the central gateway. Is it possible to configure a central gateway with regular ignition that will receive alarms, signals, etc. from the edge gateway and when the connection is broken and then restored the alarms/signals will be stored and forwarded.
Yes, this is what Edge was created for. You can develop the project(s) on the central/regular Ignition gateway and use EAM to send project(s) to the Edge gateways. On current versions of Ignition, project inheritance is also supported as the projects can be flattened by EAM on send to Edge gateways.
Edge gateways can be setup to store and forward tag history to central gateway to cover short outages (up to 7 days, I believe). Edge Panel also allows Edge gateways to run a local HMI regardless of whether central server is running. I believe alarm history is also forwarded on connection recovery, but don’t have direct experience with it.