# UDT Instance Tag Names in Historian **URL:** \ **Category:** Ignition\ **Created:** [November 27, 2019, 6:37pm UTC](https://forum.inductiveautomation.com/t/udt-instance-tag-names-in-historian/30280 "2019-11-27T18:37:35Z")\ **Posts on this page:** 1\ **Showing post:** 2
**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\ **Post date:** [November 27, 2019, 7:05pm UTC](https://forum.inductiveautomation.com/t/udt-instance-tag-names-in-historian/30280/2 "2019-11-27T19:05:58Z")
Yes - what you'll want to do is implement the `onTagsDropped` extension function on the Easy Chart component, so that you can reference an element from your UDT path when making the new tag pen on the chart. See this post for a basic example: > [@OnTagsDropped - Auto Axis to display Eng Unit Label](http://forum.inductiveautomation.com/t/ontagsdropped-auto-axis/19906/2): > > #Set up the chart defaults. default = ['DefaultName', # name '[~]DefaultPath', # tag\_path 'MinMax', # aggregation\_mode 'Default Axis', # axis 1, # subplot True, # enabled "color(255,0,0,255)", # color '', # dash\_pattern 1, # render\_style 1.0, # line\_weight 0, # shape True, # fill\_shape False, # labels '', # group\_name False, # digital False, # override\_autocolor False, # hidden True, # user\_selectable None, # sort\_order False] # user\_removable tagpens = self.tagPens for… See the manual for more information on the function and the chart component; there's a specific section on 'Extension Functions' that goes into more detail: [https://docs.inductiveautomation.com/display/DOC80/Vision+-+Easy+Chart](https://docs.inductiveautomation.com/display/DOC80/Vision+-+Easy+Chart) --- _[View the full topic](https://forum.inductiveautomation.com/t/udt-instance-tag-names-in-historian/30280)._