# A Tale of Two Tags

**URL:** <https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469>\
**Category:** Ignition\
**Created:** [May 14, 2012, 5:20pm UTC](https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469 "2012-05-14T17:20:17Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![DennisWomack](https://avatars.discourse-cdn.com/v4/letter/d/51bf81/32.png) [@DennisWomack](https://forum.inductiveautomation.com/u/DennisWomack)\
**Post date:** [May 14, 2012, 5:20pm UTC](https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469/1 "2012-05-14T17:20:17Z")

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It was the best of times it was the worst of times…

Sorry, just couldn’t resist.

I have two tags pulled from the same CLX controller.

Both are historical tags.

Both change once per hour.

One is updating in the database once per hour.

The other is updating in the database once every 10 seconds, with the same value.

Both are set as Default scan class.

Both are set as Default Historical scan class.

Can you point me where to look?

Something is obviously different, but I just don’t see it.

Thanks

Dennis

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**Author:** ![Travis.Cox](https://avatars.discourse-cdn.com/v4/letter/t/b9bd4f/32.png) [@Travis.Cox](https://forum.inductiveautomation.com/u/Travis.Cox)\
**Post date:** [May 14, 2012, 6:18pm UTC](https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469/2 "2012-05-14T18:18:25Z")

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You want to look at the scan classes for this one. When you use our historian you setup a scan class for history which is the rate to log data. By default our Default Historical scan class is a 10 second scan class. Keep in mind that we only log data when it changes. So even if they have the same scan class nothing gets put into the db until it changes.

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**Author:** ![DennisWomack](https://avatars.discourse-cdn.com/v4/letter/d/51bf81/32.png) [@DennisWomack](https://forum.inductiveautomation.com/u/DennisWomack)\
**Post date:** [May 14, 2012, 6:30pm UTC](https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469/3 "2012-05-14T18:30:59Z")

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Let me send support some screen shots.

It is easier to paste them into an email…

Thanks

Dennis

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<div class="post-metadata">

**Author:** ![Travis.Cox](https://avatars.discourse-cdn.com/v4/letter/t/b9bd4f/32.png) [@Travis.Cox](https://forum.inductiveautomation.com/u/Travis.Cox)\
**Post date:** [May 14, 2012, 6:35pm UTC](https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469/4 "2012-05-14T18:35:26Z")

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Sounds good.

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**Author:** ![Colby.Clegg](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/colby.clegg/32/3282_2.png) [@Colby.Clegg](https://forum.inductiveautomation.com/u/Colby.Clegg)\
**Post date:** [May 16, 2012, 8:46pm UTC](https://forum.inductiveautomation.com/t/a-tale-of-two-tags/4469/5 "2012-05-16T20:46:48Z")

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I’d say it must either be the (historical) deadband, or the “max executions between storing”.

If the deaband is 0, or max execs is set to 1, it would cause it to log every exec, which for the default historical deadband, is 10 seconds.