# Alarm Evaluation for OPC Tags with Bad Quality

**URL:** <https://forum.inductiveautomation.com/t/alarm-evaluation-for-opc-tags-with-bad-quality/69633>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [February 9, 2023, 3:42pm UTC](https://forum.inductiveautomation.com/t/alarm-evaluation-for-opc-tags-with-bad-quality/69633 "2023-02-09T15:42:20Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [February 9, 2023, 3:42pm UTC](https://forum.inductiveautomation.com/t/alarm-evaluation-for-opc-tags-with-bad-quality/69633/1 "2023-02-09T15:42:20Z")

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I have a UDT with many pre-defined members. Some of the members are not used on every instance, but they have an alarm attached to them. How will the alarm handle this? Will it just ignore the value and not evaluate the alarm, or will it always be in alarm? (the alarm is configured as an = 1 mode)

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<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [February 9, 2023, 9:19pm UTC](https://forum.inductiveautomation.com/t/alarm-evaluation-for-opc-tags-with-bad-quality/69633/2 "2023-02-09T21:19:31Z")

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On a related note, what happens if I try to write to a disabled tag with `system.tag.writeAsync()`?