# Data Filter Prior to Storing in Historian or Publishing to Cloud

**URL:** <https://forum.inductiveautomation.com/t/data-filter-prior-to-storing-in-historian-or-publishing-to-cloud/43318>\
**Category:** Ignition\
**Created:** [February 11, 2021, 5:19pm UTC](https://forum.inductiveautomation.com/t/data-filter-prior-to-storing-in-historian-or-publishing-to-cloud/43318 "2021-02-11T17:19:26Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![ignitionfan1](https://avatars.discourse-cdn.com/v4/letter/i/f475e1/32.png) [@ignitionfan1](https://forum.inductiveautomation.com/u/ignitionfan1)\
**Post date:** [February 11, 2021, 5:19pm UTC](https://forum.inductiveautomation.com/t/data-filter-prior-to-storing-in-historian-or-publishing-to-cloud/43318/1 "2021-02-11T17:19:26Z")

</div>

Hello,

I am trying to think of a way to clean/filter noise from tag data prior to storing it in Historian or Publishing to the cloud. Any suggestions?

Thanks

---

<div class="post-metadata">

**Author:** ![witman](https://avatars.discourse-cdn.com/v4/letter/w/d2c977/32.png) [@witman](https://forum.inductiveautomation.com/u/witman)\
**Post date:** [February 11, 2021, 6:27pm UTC](https://forum.inductiveautomation.com/t/data-filter-prior-to-storing-in-historian-or-publishing-to-cloud/43318/2 "2021-02-11T18:27:01Z")

</div>

If you can’t clean/filter the data at the source, you could use an expression tag in Ignition to do the filtering and historicize the expression tag rather than the raw tag.

---

<div class="post-metadata">

**Author:** ![Senthee\_Wu](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/senthee_wu/32/67770_2.png) [@Senthee\_Wu](https://forum.inductiveautomation.com/u/Senthee_Wu)\
**Post date:** [March 18, 2025, 4:58am UTC](https://forum.inductiveautomation.com/t/data-filter-prior-to-storing-in-historian-or-publishing-to-cloud/43318/3 "2025-03-18T04:58:16Z")

</div>

I am also facing this problem, I was planning to use this script：

```python
if(value ！= 0, value, value)

```

but I found out, I can't know what the last data was like, what should I write for this filtering script?