# Alarm Condition Reference Not Found

**URL:** <https://forum.inductiveautomation.com/t/alarm-condition-reference-not-found/34408>\
**Category:** Ignition\
**Created:** [May 4, 2020, 3:44pm UTC](https://forum.inductiveautomation.com/t/alarm-condition-reference-not-found/34408 "2020-05-04T15:44:25Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![bbranison](https://avatars.discourse-cdn.com/v4/letter/b/74df32/32.png) [@bbranison](https://forum.inductiveautomation.com/u/bbranison)\
**Post date:** [May 4, 2020, 3:44pm UTC](https://forum.inductiveautomation.com/t/alarm-condition-reference-not-found/34408/1 "2020-05-04T15:44:26Z")

</div>

For this alarm condition expression:  
if(dateDiff({[.]execution p1\_execution.LastChange},now(),“hour”)\>24,1,0)

I’m getting the following tag alarm diagnostic error:  
“activeCondition The reference ‘[.]execution p1\_execution.LastChange’ could not be located. ERROR”

I tried using tag() in the expression as well.

Any ideas for what is causing alarm?

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/3/348042ad77b3876cc28eda714fda1e0fef0612be.png)