# Tag History Sample Rate

**URL:** <https://forum.inductiveautomation.com/t/tag-history-sample-rate/36526>\
**Category:** Ignition\
**Created:** [July 9, 2020, 6:46am UTC](https://forum.inductiveautomation.com/t/tag-history-sample-rate/36526 "2020-07-09T06:46:35Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![matthew.roberts](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@matthew.roberts](https://forum.inductiveautomation.com/u/matthew.roberts)\
**Post date:** [July 9, 2020, 6:46am UTC](https://forum.inductiveautomation.com/t/tag-history-sample-rate/36526/1 "2020-07-09T06:46:35Z")

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Hi  
Is there a way to change the history sample rate based on a BOOL tag? If our plant is running we want to sample a pressure transmitter at 1sec but when not running only sample at 5 min.

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**Author:** ![BenKearney](https://avatars.discourse-cdn.com/v4/letter/b/b19c9b/32.png) [@BenKearney](https://forum.inductiveautomation.com/u/BenKearney)\
**Post date:** [July 9, 2020, 7:28am UTC](https://forum.inductiveautomation.com/t/tag-history-sample-rate/36526/2 "2020-07-09T07:28:45Z")

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You’re after a ‘driven’ tag group:

[https://docs.inductiveautomation.com/display/DOC80/Tag+Groups](https://docs.inductiveautomation.com/display/DOC80/Tag+Groups)

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**Author:** ![Sanderd17](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/sanderd17/32/8735_2.png) [@Sanderd17](https://forum.inductiveautomation.com/u/Sanderd17)\
**Post date:** [July 9, 2020, 7:35am UTC](https://forum.inductiveautomation.com/t/tag-history-sample-rate/36526/3 "2020-07-09T07:35:38Z")

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The first question before you start working on this is: do you really need this?

The historian has a deadband. So when the plant isn’t running, if the pressure remains pretty stable, it should remain within a deadband and not register new values.

When the deadband is configured correctly, it works pretty good at storing only the interesting changes.

A driven tag group (as suggested by @BenKearney), is indeed your other option.  
I certainly wouldn’t change the historian configuration programatically, since every change like that also produces DB results, and will in some cases even slow down your historical data tables.

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**Author:** ![matthew.roberts](https://avatars.discourse-cdn.com/v4/letter/m/ecd19e/32.png) [@matthew.roberts](https://forum.inductiveautomation.com/u/matthew.roberts)\
**Post date:** [July 9, 2020, 7:48am UTC](https://forum.inductiveautomation.com/t/tag-history-sample-rate/36526/4 "2020-07-09T07:48:13Z")

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Thanks for that, I am new to ignition so am used to using periodic sample rates.  
I think you 100% correct and I don’t need to worry about changing the rate and use the deadband.