# help to modify the value of a history tag to display it in a graph

**URL:** <https://forum.inductiveautomation.com/t/help-to-modify-the-value-of-a-history-tag-to-display-it-in-a-graph/45395>\
**Category:** Ignition\
**Created:** [April 8, 2021, 3:55pm UTC](https://forum.inductiveautomation.com/t/help-to-modify-the-value-of-a-history-tag-to-display-it-in-a-graph/45395 "2021-04-08T15:55:53Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![eponce](https://avatars.discourse-cdn.com/v4/letter/e/35a633/32.png) [@eponce](https://forum.inductiveautomation.com/u/eponce)\
**Post date:** [April 8, 2021, 3:55pm UTC](https://forum.inductiveautomation.com/t/help-to-modify-the-value-of-a-history-tag-to-display-it-in-a-graph/45395/1 "2021-04-08T15:55:53Z")

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I am looking for a way to be able to modify the value of a date range so that it is displayed in a graph, in a table if I could modify the operation but I cannot find how to do it in a graph, the value I am trying to put is this: @(ctim\*-1.38)+203.17@  
I also tried writing a script but this option doesn’t work for me:  
chart.setValue (data [@ (ctim \* -1.38) + 203.17 @])  
I don’t know if he is declaring it right or wrong.  
thanks for your kind help  
greetings from Mexico