# Need Tag and Historical help

**URL:** <https://forum.inductiveautomation.com/t/need-tag-and-historical-help/39677>\
**Category:** Ignition\
**Created:** [October 14, 2020, 6:38pm UTC](https://forum.inductiveautomation.com/t/need-tag-and-historical-help/39677 "2020-10-14T18:38:14Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jason.schwenk](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jason.schwenk/32/18822_2.png) [@jason.schwenk](https://forum.inductiveautomation.com/u/jason.schwenk)\
**Post date:** [October 14, 2020, 6:38pm UTC](https://forum.inductiveautomation.com/t/need-tag-and-historical-help/39677/1 "2020-10-14T18:38:14Z")

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Hi everyone  
Pretty new to ignition design and I am having an issue figuring out an upcoming project.  
I have no problem with tags, historical and charting for tags that are constantly being polled like a pressure reading or other like that. What I cant seem to figure out is how to get point data saved with having the same data be populated into the historical sever every poll cycle. What I want is to have a data point entered in an HMI and have that point and only that point and timestamp recorded into historical so that I can trend measurements over time.

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**Author:** ![dkhayes117](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/dkhayes117/32/68344_2.png) [@dkhayes117](https://forum.inductiveautomation.com/u/dkhayes117)\
**Post date:** [October 14, 2020, 6:59pm UTC](https://forum.inductiveautomation.com/t/need-tag-and-historical-help/39677/2 "2020-10-14T18:59:35Z")

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You can set the `Historical Scanclass` to `<Evaluate On Change>`, this will only log the history when the value changes.