[00:00] Ignition clients depend on a stable connection with a gateway to function. If that connection is lost, the client will suspend operations as it attempts to reconnect. This can be a problem when clients need to monitor critical operations. In this lesson, I'll demonstrate how to configure a local client fallback. With a local client fallback, if connection to a central gateway is lost, then a Vision project on the machine that's running the client will be launched. This project can be set up with the minimum amount of realtime information required to keep operations running until that connection can be reestablished. I've created an environment to replicate a scenario where I have a local Ignition installation onsite with me and a gateway that's in a different centralized location. I'll start by showing my project and the designer for my central gateway. My central gateway is a standard Ignition installation and has connections to things like my database server. I also have a designer open for the project on my local gateway. In my scenario, this gateway is an Edge installation with connections to local devices.

[01:04] It's physically separated from the central gateway and the network connection between the two isn't always reliable. This project is stripped down and doesn't contain some of the same windows that the project on the central gateway does. An important note about this Edge gateway is that it's also installed on the same machine that I'm going to be launching clients from. When the connection to the central gateway is up, I want operators to use that project. However, when that connection goes down, I want them to still be able to continue operations at the local site with the Edge project. In order to accomplish this, I'll need to configure a local client fallback on the local gateway. I'll start by opening the Edge Gateway's config page and navigating to System, Overview, and Gateway Settings. Then I'll need to scroll down to the Local Vision Client Fallback section. I'll click this checkbox to enable local fallback, and then I need to specify the project to use during fallback. This is an Edge gateway, so the project is named Edge. This other property here controls how long the client will wait before switching to the local gateway's project.

[02:03] I'm gonna leave this at the default of 60 seconds, but if you wanted to increase or decrease that, this is the place to do it. It's also important to note that port 6501 must be open on the local machine in order to use local client fallback. Once I'm finished with these configurations, I'll scroll down and click save changes. Now I'll open up a client for the Central Gateway project. Under ideal conditions, operators will use this project and get access to everything Central Gateway has access to. However, in the event of a network problem, which I'll trigger on my other screen, communications will drop and the project won't be accessible. Then operators will see this Gateway connection lost window. This window will notify them that the connection is lost, the local fallback project will be detected, and a countdown for whatever value was in the Seconds Before Failover property we saw in the local gateway will start. Once the timer reaches zero, it will automatically switch to the Fallback project. However, failover can also be triggered manually by clicking this button here.

[03:14] Now my operators can continue working in this project, which gives them just enough to keep operations running while communications are down. After the Fallback project is launched, it won't automatically transfer back to the central gateway when communications are restored. However, you can create your own functionality to accomplish this. My project monitors the status of the central gateway and displays it on this label here. I'll restore the connection and you can see that my label will update and I've added a button to the window that will reveal itself. Clicking that will retarget back to the Central Gateway Project. To see an example of how to retarget via a client timer script, check out the user manual link in the resources below the video. To further extend the functionality of what we looked at, in this video, you can store historical data on the Edge Gateway's temporary provider, and sync that with the central gateway when the connection is restored.

[04:06] To see how to configure this, check out our other video called Setting Up Edge Sync Services.