This lesson is part of the Tags in Ignition course. You can browse the rest of the lessons below.

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Tags in Ignition

Description

Learn the basics of Tags in Ignition, including their purpose and use.

Video recorded using: Ignition 8.0

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[00:00] In this lesson, we'll talk about tags in Ignition. A tag is an object that contains a value and then value is usually derived by some other means, such as it's pulled from a physical device somewhere on our network, or there's a script, or a query running and the results of those could then be passed to a tag. Tags are the main way to move values and data around your projects. There are a number of reasons for this, but a very obvious one is that all of the various resources inside of a project have access to the tag system. So at some point, when Ignition's been installed, you'll open the designer and you'll see this area titled tag browser. The tag browser is the way you create tags as well as modify preexisting ones. We'll go more in depth on creating tags a little bit later, but the short version of it is you can always open up the OPC browser and then drag some tags in from your various device connections or you can always select a folder hit the add tag drop down and then pick one of the various types to manually create a tag. We'll talk about the various types of tags what they do as well as how to create them later on. Now we can see in my tag browser, I have a couple of tags I have created already so we'll go down the sine folder here. You can see that I have OPC tags so it shows you the type of the tag as well as the value on the tag. And we can see that they're actually executing. They're running, they're getting new values. If I were to double click on one of these tags, so if I double click on sine zero here, that opens up our tag editor and we'll talk about the tag editor later on. But from the tag editor, I can make changes to this tag. So for example, I can change the value source which changes the type, so I can switch this tag to one of the other types you saw earlier. That of course would change how the tag gets its value, though. And if we kind of scroll down this list here you can see there's all kinds of different properties for changing how the numbers displayed what the minimum and maximum values should be if you wanted to add some documentation or tool tips. There's alarms, there's history, all these kind of useful settings you can apply directly to the tag. Now when it comes to polling on a tag there's this concept of a tag group. You can effectively think of the tag group as the pole rate. Technically, it's a bit more than that. But you wouldn't be wrong in assuming that. So somewhere there's this thing called default, that's a tag group, it's executing at some rate. Whenever that executes, this tag here gets an updated value. Now if we close our tag editor here and I go back to my tag browser, as an important concept, you're going to want to understand that tags actually live outside of your project. So I'm looking at a project in my designer here. I have a bunch of tags, but these tags actually are available to all of my projects. So if I were to head up to the file menu here, in the designer and if I go to new, and I create a brand new project, I won't worry about saving, 'cause I haven't really made any changes. We can give this new project a name. I'll create the new project. And we see that the new project's been created. It doesn't have any resources inside of it so we don't have any vision windows or prospective views. But if I head down to the tag browser here we go back to that tags folder, you can see that I still have my tags from earlier. So these tags sort of live outside of your projects. If you delete a project, it doesn't necessarily delete your tags. Now when it comes to where the tags fit in the larger Ignition ecosystem here, tags live on the gateway. So if you close all of your designers, you close your vision clients, and your prospective sessions, all your visualization options, you just close them all down, but the gateway's still up and running, your tags are still executing. So you can turn on history, you can create alarms on those tags there. The gateway's still executing, it's still recording those values. And if you've configured notifications, then those will be sent out when your alarms go active.

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