# Tag History Value Mode and Wrong History Values

**URL:** <https://forum.inductiveautomation.com/t/tag-history-value-mode-and-wrong-history-values/31453>\
**Category:** Ignition\
**Tags:** ignition79\
**Created:** [January 21, 2020, 8:44am UTC](https://forum.inductiveautomation.com/t/tag-history-value-mode-and-wrong-history-values/31453 "2020-01-21T08:44:27Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![pgmo](https://avatars.discourse-cdn.com/v4/letter/p/d07c76/32.png) [@pgmo](https://forum.inductiveautomation.com/u/pgmo)\
**Post date:** [January 21, 2020, 8:44am UTC](https://forum.inductiveautomation.com/t/tag-history-value-mode-and-wrong-history-values/31453/1 "2020-01-21T08:44:27Z")

</div>

Hi,  
I’m wondering what’s really happening when I set a _Tag History Value Mode_ to **Analog**.  
I tried what follows

- set a `motor_rpm` Tag History Value Mode to **Discrete** : plots on the Easy Chart component as well as points I can get with `system.tag.queryTagHistory` are correct, i.e. they just look as I expected;
- set the same tag Value Mode to **Analog** : plots and points have nothing to do with the history of the tag at all (values are really far from the rpm motor values I saw in realtime).

I read this part of the Ignition manual:  
[https://docs.inductiveautomation.com/display/DOC79/Configuring+Tag+Historian](https://docs.inductiveautomation.com/display/DOC79/Configuring+Tag+Historian)  
however cannot grasp the reason why my results are not as expected.

(Ignition version: **7.9.9 (b2018081621)**)

Thanks in advance, regards