# Value Sub-properties

**URL:** <https://forum.inductiveautomation.com/t/value-sub-properties/11393>\
**Category:** Ignition\
**Created:** [March 21, 2016, 7:36pm UTC](https://forum.inductiveautomation.com/t/value-sub-properties/11393 "2016-03-21T19:36:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Keith.Britton](https://avatars.discourse-cdn.com/v4/letter/k/f05b48/32.png) [@Keith.Britton](https://forum.inductiveautomation.com/u/Keith.Britton)\
**Post date:** [March 21, 2016, 7:36pm UTC](https://forum.inductiveautomation.com/t/value-sub-properties/11393/1 "2016-03-21T19:36:48Z")

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I’ve written a script that runs on the gateway that detects a change in a tag that I suspect is having sampling-related problems (very infrequently returns nulls instead of integer values). Ignition 7.6.4, BTW. Anyhoo, I want the tag change to trigger on [tag]Value.Quality but it seems to trigger on any attribute listed under Value – in this case [tag]Value.value, which is changing roughly once every 65-75 seconds. Any way to perform a comparison to see if just the .Quality attribute has changed? Thanks for any assistance.

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**Author:** ![Keith.Britton](https://avatars.discourse-cdn.com/v4/letter/k/f05b48/32.png) [@Keith.Britton](https://forum.inductiveautomation.com/u/Keith.Britton)\
**Post date:** [March 22, 2016, 4:06pm UTC](https://forum.inductiveautomation.com/t/value-sub-properties/11393/2 "2016-03-22T16:06:43Z")

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I figured it out. I added a conditional test:

`if (str(newValue.quality) != "Good") :
	... takeNoPrisoners() ...
else :
	... takeSomePrisoners() ...`  
Duh!