How to store data from a dataset in a memory tag?

#1

Good night. I am new to Ignition and as I am studying I have had many doubts and I believe many of them quite simple. My question is, how do I write data from a dataset to a memory tag?
If you can explain me the walkthrough thank you very much. because I don’t understand where, for example, the production values ​​of cans, spoilages, efficiency come from. and all these values ​​are stored in memory tags. and I believe such values ​​come from datasets. My question is: if they come from datasets, how can I write this data to memory tags. Thankful!!!

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#2

You mean you inherited an Ignition project, and you don’t know where certain data is coming from?

This is actually quite a difficult one, as almost anything in Ignition has access to the tags. You can bind a dataset tag to a table component, and let the user update the table directly.

Or you can create a dataset in a script (system.dataset.toDataSet) and write it to a tag (system.tag.write). And that script can be literally anywhere (on client screens, on a gateway timer, triggered on other tag changes, …)

For your example, given it’s historical data. It’s most likely that the origin of the data is a database. Either a native Ignition Historian database (which is used for trending), or database with custom made tables (where changes may be written to from Ignition or from somewhere else). It’s unlikely that all historical data is stored in a memory tag directly, as that would cause huge memory usage.

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#3

Watch some videos on www.inductiveuniversity.com if you haven’t. They will get you up to speed with Ignition.

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#4

Another thing you can do is use the Find/Replace (Ctrl+F) tool to search through the project. It can search through the entire project and find where things are used. I use it when I can’t remember how I programmed something. As I get older, I seem to use it a bit more…

A couple of things to note:

  • If the action is happening in a different project, the Find/Replace tool won’t find it.
  • Depending on the size of the project, a search can take a while. Keep a refreshing beverage nearby. :slight_smile:
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