# Stopping Tag Historian

**URL:** <https://forum.inductiveautomation.com/t/stopping-tag-historian/17519>\
**Category:** Ignition\
**Created:** [March 27, 2018, 2:43pm UTC](https://forum.inductiveautomation.com/t/stopping-tag-historian/17519 "2018-03-27T14:43:30Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![leonardjamiej](https://avatars.discourse-cdn.com/v4/letter/l/e19b73/32.png) [@leonardjamiej](https://forum.inductiveautomation.com/u/leonardjamiej)\
**Post date:** [March 27, 2018, 2:43pm UTC](https://forum.inductiveautomation.com/t/stopping-tag-historian/17519/1 "2018-03-27T14:43:30Z")

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Is it possible to start and stop Tag Historian, so that data is only collected when desired?

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**Author:** ![Paullys50](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paullys50/32/3324_2.png) [@Paullys50](https://forum.inductiveautomation.com/u/Paullys50)\
**Post date:** [March 27, 2018, 3:52pm UTC](https://forum.inductiveautomation.com/t/stopping-tag-historian/17519/2 "2018-03-27T15:52:30Z")

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You probably need to look into a new scan class, using the “driven” mode and assign the tags you want to start/stop to that scan class.

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**Author:** ![leonardjamiej](https://avatars.discourse-cdn.com/v4/letter/l/e19b73/32.png) [@leonardjamiej](https://forum.inductiveautomation.com/u/leonardjamiej)\
**Post date:** [March 27, 2018, 4:10pm UTC](https://forum.inductiveautomation.com/t/stopping-tag-historian/17519/3 "2018-03-27T16:10:33Z")

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Thanks Paullys50,  
I only show two scan class options, Default and Default Historical to choose between.

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<div class="post-metadata">

**Author:** ![leonardjamiej](https://avatars.discourse-cdn.com/v4/letter/l/e19b73/32.png) [@leonardjamiej](https://forum.inductiveautomation.com/u/leonardjamiej)\
**Post date:** [March 27, 2018, 4:13pm UTC](https://forum.inductiveautomation.com/t/stopping-tag-historian/17519/4 "2018-03-27T16:13:36Z")

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I spoke too soon. I found where to edit the scan class.

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**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [March 27, 2018, 4:23pm UTC](https://forum.inductiveautomation.com/t/stopping-tag-historian/17519/5 "2018-03-27T16:23:59Z")

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Keep in mind that the tag historian is really not built around this kind of workflow. Tag historian and it’s sliding window algorithm/compression is best for constant value changes at a reasonably consistent sample rate. If you want event-driven value storage, transaction groups are really the best choice.