# Alerting setpoint expressions

**URL:** <https://forum.inductiveautomation.com/t/alerting-setpoint-expressions/8264>\
**Category:** Ignition\
**Created:** [April 4, 2014, 7:22pm UTC](https://forum.inductiveautomation.com/t/alerting-setpoint-expressions/8264 "2014-04-04T19:22:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![geisslert](https://avatars.discourse-cdn.com/v4/letter/g/7ea924/32.png) [@geisslert](https://forum.inductiveautomation.com/u/geisslert)\
**Post date:** [April 4, 2014, 7:22pm UTC](https://forum.inductiveautomation.com/t/alerting-setpoint-expressions/8264/1 "2014-04-04T19:22:00Z")

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I am in the process of configuring alerts on certain tags. I need to reference other tag values for low and high setpoints. So for this particular alert i would like to set the low and high setpoints to within 50% of the actual tag value. So… I am attempting to enter an expression in the setpoint to do the math. Is this even possible?

Thanks guys!

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**Author:** ![adamaustin](https://avatars.discourse-cdn.com/v4/letter/a/5f8ce5/32.png) [@adamaustin](https://forum.inductiveautomation.com/u/adamaustin)\
**Post date:** [April 4, 2014, 7:42pm UTC](https://forum.inductiveautomation.com/t/alerting-setpoint-expressions/8264/2 "2014-04-04T19:42:27Z")

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I think you’ll need to create a new Expression tag for this.

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**Author:** ![geisslert](https://avatars.discourse-cdn.com/v4/letter/g/7ea924/32.png) [@geisslert](https://forum.inductiveautomation.com/u/geisslert)\
**Post date:** [April 4, 2014, 8:00pm UTC](https://forum.inductiveautomation.com/t/alerting-setpoint-expressions/8264/3 "2014-04-04T20:00:33Z")

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Was trying to avoid having to create more tags - seems a bit cumbersome…

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**Author:** ![greg.simpson](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/greg.simpson/32/3135_2.png) [@greg.simpson](https://forum.inductiveautomation.com/u/greg.simpson)\
**Post date:** [April 17, 2014, 9:39pm UTC](https://forum.inductiveautomation.com/t/alerting-setpoint-expressions/8264/4 "2014-04-17T21:39:13Z")

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adamaustin is correct, you would need to create an expression tag for this.

The alternative would be to use 7.6 where expressions like this can be used.