[00:00] In this lesson, I'll demonstrate the Tag Reference Tracker tool that was introduced in 8.1.34. The Tag Reference Tracker is a tool that was introduced to identify which resources are using a tag. I'll demonstrate the functionality with a memory tag that I've created in my default tag provider. You can access the tool by right clicking on a tag and selecting view tag diagnostics. This will open a window with three different tabs, Diagnostics, Active Subscriptions, and Reference Log. The first tab is the Diagnostics tab, which contains information that used to exist within the Tag Editor, but it's been moved here to this new location. The other two tabs are new and have been added as part of the Tag Reference Tracker. The Active Subscriptions tab is a place to check for anything that is currently subscribed to your tag, and it'll tell when it was first referenced. I currently have something subscribed to this tag, and if I expand this record, I see that it's coming from an expression on the text property of a label. Also, the record shows a hierarchy of the project that this exists in, which module it's coming from, and then the view and component down to the function.

[01:07] This helps me find the actual location of this source in my project, and then I can go and investigate that label and its expression, if I want. I could also double click this record to be taken to the resource in question. I can also click this Designer icon here to show any references that are originating from a Designer session, for example, my tag browser. The next tab is the Reference Log, which shows historical interactions with this tag, such as reads, writes, subscriptions, and configuration changes. Just like the Active Subscriptions tab, I can toggle the Designer interactions, and this will show me what and where the source of the interaction is. Additionally, this will show me what type of interaction happened and then when it was last referenced. To demonstrate this, I'll launch a Perspective session. I have two buttons on my view and one line of code each to read and write to my tag. If I click the read button and fire the script, I'll go back to the Reference Log and I see that there's a new record that shows that a read occurred.

[02:03] If I click the write button, then I get the same thing, but for a write interaction, and if I were to click the write button multiple times, it increments the update field and I can see how often this type of interaction happens. If I want, I can also click this erase icon and clear out the Reference Log records for this particular tag. Note that this permanently removes the records. The records themselves are stored in a SQLlite database that exists on the gateway in the Ignition install directory. I'll show the path to this directory below. Each SQLlite database in this directory will be specific to a tag provider. So, if I create new tag providers that have the reference store enabled, another database would be created to hold records for tags within that provider. If you'd ever like to back these up, just know that they won't be included in a gateway backup due to their size, so they'll need to be manually backed up. In fact, depending on the number of references in the project, they may grow to be quite large. If available disc space becomes a concern, this functionality can be disabled.

[03:05] Speaking of which, it can be enabled or disabled from the gateway webpage by going to config > tags > realtime > clicking edit on a provider > showing advanced properties > and then by enabling or disabling this property. For non realtime providers, like the system provider or for MQTT tags, it can be enabled or disabled via config > gateway settings > enable tag reference tracker store. New gateways will have this feature enabled by default. However, any existing gateways that are upgraded to version 8.1.34 or beyond, will have this feature disabled by default, and it will need to be turned on.