Storing a Tag Value to the Historian Regardless of Value Change

Ignition
1

Hey all,

I am currently developing a traceability solution aimed at ensuring a group of tags' present values are stored in the historian even when the value of said tag does not change and therefore does not trigger an onChange historical entry. One additional requirement is each historian record that is caused by this event should only store a single entry of all present tag values - no polling based on a condition.

The concept I am exploring involves configuring a dedicated Tag Group that is tied to a collection trigger tag. When the value of this trigger tag changes, it would initiate a process to manually register (or force a historical write of) the current values of a defined set of other tags, regardless of whether those individual tag values have changed since their last recorded entry. I'm thinking the requirement of only one record stored per collection trigger event would be tied to the "one shot" property within the Driven Tag Group Mode.

I have the concept in mind, but I'm wondering if anyone has encountered this scenario and has some prior knowledge of implementation that could aid in configuration to accomplish this.

Thanks!

2

Couldn't you just configure the Max Time to a non zero value for each tag?

Or do you want it strictly event based?

3

I only want to collect the values into the historian given that trigger tag has updated, so strictly event-based for the collection trigger tag value.

4

Checked the documentation and found a method to manually store history through scripting. I think configuring the tags without history enabled and using a Gateway Event Tag Change Script with the following method call for the group of tags I want to store history for would work: system.tag.storeTagHistory.

5

The historian is really bad at this. Use the SQL Bridge module with a dedicated DB table, or script such yourself.

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6

This is the only way that I am aware of to store multiple tags based on the value of a different tag and still use the Tag History tables.

There are advantages to using a wide table format rather than the Tall format which is used by the Historian. However, if you have infrastructure already in place which is using the historian tables and you want this information to be available in that way, this is really the only way.

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