# What are "array eval" key in boolean array UDTs?

**URL:** <https://forum.inductiveautomation.com/t/what-are-array-eval-key-in-boolean-array-udts/44454>\
**Category:** Ignition\
**Created:** [March 15, 2021, 2:53am UTC](https://forum.inductiveautomation.com/t/what-are-array-eval-key-in-boolean-array-udts/44454 "2021-03-15T02:53:42Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![bradley.falzon](https://avatars.discourse-cdn.com/v4/letter/b/e495f1/32.png) [@bradley.falzon](https://forum.inductiveautomation.com/u/bradley.falzon)\
**Post date:** [March 15, 2021, 2:53am UTC](https://forum.inductiveautomation.com/t/what-are-array-eval-key-in-boolean-array-udts/44454/1 "2021-03-15T02:53:42Z")

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I’ve just created a UDT to store some of our PLC alarm status flags which are just integers with each bit referencing a different alarm.

I’ve imported these paths as Boolean Array and can manipulate it relatively OK.

But I noticed when this same structure was imported in a UDT, I have a new property called “array eval”, which looks like it does a small amount of bitwise help:

![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/8/c86d6c9dd6812ec09fd8ea4c4069a9cd52df04c2.png)

This looks like it could be useful, but it doesn’t appear to work (some bits were set and set to alarm if those bits were set).