# Tag alarm for null value

**URL:** <https://forum.inductiveautomation.com/t/tag-alarm-for-null-value/56627>\
**Category:** Ignition\
**Created:** [February 28, 2022, 4:16pm UTC](https://forum.inductiveautomation.com/t/tag-alarm-for-null-value/56627 "2022-02-28T16:16:09Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![jimmy.crotts](https://avatars.discourse-cdn.com/v4/letter/j/c68b51/32.png) [@jimmy.crotts](https://forum.inductiveautomation.com/u/jimmy.crotts)\
**Post date:** [February 28, 2022, 4:16pm UTC](https://forum.inductiveautomation.com/t/tag-alarm-for-null-value/56627/1 "2022-02-28T16:16:09Z")

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Occasionally we loose connectivity to a device that is being recorded in a SQL database. I would like to alarm based off of getting a null value returned in a tag. Is this possible?

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**Author:** ![LCao](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lcao/32/35341_2.png) [@LCao](https://forum.inductiveautomation.com/u/LCao)\
**Post date:** [June 8, 2022, 5:12pm UTC](https://forum.inductiveautomation.com/t/tag-alarm-for-null-value/56627/2 "2022-06-08T17:12:36Z")

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Hi Jimmy,

From my test, when a device lost connection to Gateway, the tags from that device tend to keep the last known value instead of updating to ‘null’. So I think configuring an alarm using `Bad Quality` Mode might be more accurate in your case as the tag quality will be updated once the device lost connection. See more information in our User Manual: [Configuring Alarms - Ignition User Manual 8.1 - Ignition Documentation](https://docs.inductiveautomation.com/display/DOC81/Configuring+Alarms#ConfiguringAlarms-AlarmModesandSetpoints)  
[Tag Alarm Properties - Ignition User Manual 8.1 - Ignition Documentation](https://docs.inductiveautomation.com/display/DOC81/Tag+Alarm+Properties#TagAlarmProperties-ReferenceTable)