# Perspective Power Chart - Predefine Pens

**URL:** <https://forum.inductiveautomation.com/t/perspective-power-chart-predefine-pens/45568>\
**Category:** Ignition\
**Tags:** perspective\
**Created:** [April 14, 2021, 5:32am UTC](https://forum.inductiveautomation.com/t/perspective-power-chart-predefine-pens/45568 "2021-04-14T05:32:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AnthonyF](https://avatars.discourse-cdn.com/v4/letter/a/aca169/32.png) [@AnthonyF](https://forum.inductiveautomation.com/u/AnthonyF)\
**Post date:** [April 14, 2021, 5:32am UTC](https://forum.inductiveautomation.com/t/perspective-power-chart-predefine-pens/45568/1 "2021-04-14T05:32:54Z")

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Hi All,  
I’ve noticed the Power Chart allows bindings to the Pen Source object, but the documentation does not give much detail on what is expected here, other than a value or string.

Can anyone shed any light on how to use this? Should it be the path to the tag as that doesn’t seem to work?

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**Author:** ![kirsten.chambers](https://avatars.discourse-cdn.com/v4/letter/k/48db29/32.png) [@kirsten.chambers](https://forum.inductiveautomation.com/u/kirsten.chambers)\
**Post date:** [April 14, 2021, 6:26am UTC](https://forum.inductiveautomation.com/t/perspective-power-chart-predefine-pens/45568/2 "2021-04-14T06:26:34Z")

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The format for pens’ data source property is the same as documented in the `config.tagBrowserStartPath` property, i.e.

`histprov:Sample_SQLite_Database:/drv:My_Gateway:My_Tag_Provider:/tag:My_Folder/Another_Folder`

This didn’t help me at all, as this format is confusing to try and handcraft when you don’t know the db driver offhand. What I did instead was use the tag browser portion of the power chart component to add a pen and observe the format for my gateway setup. If you leave the `props.config.tagBrowserStartPath` blank, open the tag browser, and wait a bit for it to populate, you should be able to see all of your tag providers and poke around for a tag you can add. From that, you can see the format you need from `props.pens[0].data.source` property, and you can hopefully figure out how to modify it however you need from there.