# Engineering Units from OPC

**URL:** <https://forum.inductiveautomation.com/t/engineering-units-from-opc/105805>\
**Category:** Ignition\
**Tags:** scripting, perspective\
**Created:** [May 1, 2025, 11:52pm UTC](https://forum.inductiveautomation.com/t/engineering-units-from-opc/105805 "2025-05-01T23:52:24Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ethan.vazquez](https://avatars.discourse-cdn.com/v4/letter/e/cdc98d/32.png) [@ethan.vazquez](https://forum.inductiveautomation.com/u/ethan.vazquez)\
**Post date:** [May 1, 2025, 11:52pm UTC](https://forum.inductiveautomation.com/t/engineering-units-from-opc/105805/1 "2025-05-01T23:52:24Z")

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Hello all! I'm wondering how best to get custom engineering units from OPC. Our OPC server provides UCUM engineering units and there doesn't seem to be a simple way to link this when I create a new OPC tag. For instance, one of the nodes we have provides a value (double) and Engineering units, of which the value is in degrees:

Value EUInformation [NamespaceUri="[ucum.org](http://ucum.org)", UnitId="0", DisplayName="deg", Description="deg"]

How could I script / link this so that the tag has the information?

Thanks,  
Ethan

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**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\
**Post date:** [May 2, 2025, 12:00am UTC](https://forum.inductiveautomation.com/t/engineering-units-from-opc/105805/2 "2025-05-02T00:00:08Z")

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I would make a script that takes a tag path as a parameter and uses [system.opc.readValue | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/appendix/scripting-functions/system-opc/system-opc-readValue) to grab the EU and add it to a tag using [system.tag.configure | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/appendix/scripting-functions/system-tag/system-tag-configure) and have a gateway event that runs this script as needed for each tag that is able to provide this data.