Now that we've created a project, lets launch a Client to see it in action.
admin/passwordcredentials will work.
Click on the notification and the Client will update itself.
You can launch as many Clients as you want! If you've got other computers on the same network as the Gateway computer try launching on them too. Make sure that your Gateway computer doesn't have a Firewall enabled, otherwise, it is allowing traffic on port 8088 - the default port for the Ignition web server.
Ignition Clients are fully dependent on being able to communicate with a Gateway. If Gateway communication is lost, the Client suspends operation while it attempts to reconnect with the Gateway. This can be a problem when you need the Client to monitor critical operations on a plant floor.
Ignition provides a local Client fallback mechanism that lets you to use a Gateway running on the local machine. In normal operation, your Client can connect to a central Gateway located somewhere on the network. The central Gateway would be responsible for all data aggregation, such as storing historical data in a database. But if communication to the central Gateway is lost, the Client can automatically retarget to a project that you specify in the local Gateway. This project should contain the minimal realtime information that you need to keep your operation running. Note that in order to use local fallback, port 6501 must be open on the local machine.
To enable local fallback, do the following steps:
When local fallback is enabled, the Client attempts to open port 6501 on the local machine. If the port can be opened successfully, the Client reads fallback settings from the local Gateway and shows a Fallback Project button on the bottom of the Gateway Connection Lost window. You can click this button at any time to load the fallback project, or simply wait for the fallback project to automatically load. You may want to set the local Client to automatically log in to avoid typing in a username and password when the Client loads. This can be set in the Login section of the project's properties.
Testing local fallback is highly recommended before you start to depend on it in a production setting. The easiest way to test fallback is to simply unplug the network cable to the Client machine, or disable the network card on the machine. If the Fallback Project button is not visible on the Gateway Connection Lost window, check your local Gateway console and verify that the message Started Fallback Socket on port 6501 is present in the console. Any other error message related to the Fallback Socket Controller indicates that some other problem has occurred (most likely the port cannot be reserved) and local fallback is not available to Clients.
Client Retargeting is the method by which Clients running a particular project switch to a different project on the fly, even if the other project is hosted on a different Ignition Gateway. Retargeting is a key feature used to build distributed systems. It allows you switch between projects and servers as easily as switching between windows. Using Retargeting, even geographically dispersed projects can be presented as a single cohesive unit.
In many circumstances, the communication loss to the central Gateway is only a temporary event. To minimize the amount of time that you need to run the local Client, you can add some functionality to the Client that allows you to check on the status of the central Gateway. One way to do this is to add a timer script to your local Client. The script calls the
system.util.getGatewayStatus() function at regular intervals and updates an item such as a Client tag with the Gateway status. Then, you can bind an indicator component to the Client tag and get ongoing visual feedback on the central Gateway status. As soon as you can confirm that the central Gateway is running again, you can call the
system.util.retarget() function in a button to seamlessly direct the Client back to the central Gateway.