How Things Work - Tag history setting

hi
Let's assume that in tag history settings sample mode is set to tag group and tag group is driven class.
Is it still possible to record the data on change basis rather than periodic driven rate ?

You can set the tag to store 'on change', but as it only changes with the driven rate, it's functionally the same.

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hm any chance you clarify this as i would like to understand that?
When history recording is on change the "driven tag recording" is not available as an option or i cant see it. By "driven tag" i mean storing only when for example "machine_on" signal is on.

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The driven will dictate when the tag value updates on the Ignition, a direct tag connection will read the PLC every x amount of of seconds, while driven will vary the rate it reads based on your expression.

Storing on change will only store the value when the value changes, if you don't update the value then it won't change, so won't store.

If you want more fine control over when data is stored, you'll want to look into the transaction groups.

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Great info many thanks.
What about scenario where i am setting up history on the tag which is coming from the remote tag provider? I guess in that case "driven" concept does not apply as the tag is controlled by the source tags settings - so i would need to change the settings on that tag to stop updating if the "machine_on" signal is OFF?

Not sure when it comes to the remote tag providers if you could change it, but if you want to have very fine control of when data is uplaoded you'll want transaction groups set up. Using the SQL Bridge Module

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yes transaction manager would give an ultimate control

You can have the most control by scripting in Gateway Tag Change events.

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if i understood -gateway tag change script gives us a coding space to build the logic and then trigger " system.tag.storeTagHistory" to save history of the data - is it correct?

You can do that, or you can insert data into a database in any way you see fit. You do not have to use Ignitions History module or Transaction Groups at all, so long as you have a full version of Ignition. With Edge, I believe you have to have another module to enable scripting (I'm not sure I do not have edge).

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Yes that is a good point. In full gateway we have an ultimate control over data storage to the database as long as it is relational database as ignition does not support time series databases if i remember correctly.

You can connect Ignition to anything that has a JDBC driver, pretty easily.

With a custom module, you can do more exotic things like "native" history integration with InfluxDB or Canary.

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thanks for correcting me. i have a full picture now.
much appreciated

Even with scripting enabled, you don't get database connections, so no. With Edge, you must use its historian, and either push with sync services or publish to an MQTT broker.

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