# openHistorian Data Walker Utility Filter Expression

**URL:** <http://discussions.gridprotectionalliance.org/t/openhistorian-data-walker-utility-filter-expression/1479>\
**Category:** openHistorian\
**Created:** [March 16, 2026, 6:59pm UTC](http://discussions.gridprotectionalliance.org/t/openhistorian-data-walker-utility-filter-expression/1479 "2026-03-16T18:59:05Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jarurlaj](http://discussions.gridprotectionalliance.org/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@jarurlaj](http://discussions.gridprotectionalliance.org/u/jarurlaj)\
**Post date:** [March 16, 2026, 6:59pm UTC](http://discussions.gridprotectionalliance.org/t/openhistorian-data-walker-utility-filter-expression/1479/1 "2026-03-16T18:59:05Z")

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Hi guys,

I was just looking for an example of the filter expression needed for the Data Walker Utility. I’m interested in trending a singular point. Would the Point # or PointTag (openMic) be necessary?

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**Author:** ![ritchiecarroll](http://discussions.gridprotectionalliance.org/user_avatar/discussions.gridprotectionalliance.org/ritchiecarroll/32/2_2.png) [@ritchiecarroll](http://discussions.gridprotectionalliance.org/u/ritchiecarroll)\
**Post date:** [March 18, 2026, 3:41pm UTC](http://discussions.gridprotectionalliance.org/t/openhistorian-data-walker-utility-filter-expression/1479/2 "2026-03-18T15:41:14Z")

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There are a few tools that reference the name “Data Walker”, can you elaborate on the GitHub repo for this tool for clarity?

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**Author:** ![jarurlaj](http://discussions.gridprotectionalliance.org/letter_avatar_proxy/v4/letter/j/9dc877/32.png) [@jarurlaj](http://discussions.gridprotectionalliance.org/u/jarurlaj)\
**Post date:** [March 18, 2026, 3:53pm UTC](http://discussions.gridprotectionalliance.org/t/openhistorian-data-walker-utility-filter-expression/1479/3 "2026-03-18T15:53:59Z")

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Not sure about it’s location on Github, but the utility is called Historian CSV Dump on on our system.

 ![Screenshot 2026-03-18 114725](http://discussions.gridprotectionalliance.org/uploads/default/original/2X/a/ac56c3a080a784de2f3fff6c829e422f2e9b0d5a.png)

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**Author:** ![StephenCWills](http://discussions.gridprotectionalliance.org/user_avatar/discussions.gridprotectionalliance.org/stephencwills/32/20_2.png) [@StephenCWills](http://discussions.gridprotectionalliance.org/u/StephenCWills)\
**Post date:** [March 18, 2026, 4:33pm UTC](http://discussions.gridprotectionalliance.org/t/openhistorian-data-walker-utility-filter-expression/1479/4 "2026-03-18T16:33:46Z")

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I believe that CSV Dump tool is a modified version of the Historian Data Walker which does not use the `Point List / Filter Expression` field. Furthermore, that tool can only show you point counts by device and therefore cannot be used for trending data.

If you want to trend data for a single data point, I recommend using the `Trend / Export` page in the openHistorian web interface instead. It supports trending one or more data points on a chart and also exporting those data points to CSV files for offline analysis.