# Expression tag is slow sometimes

**URL:** <https://forum.inductiveautomation.com/t/expression-tag-is-slow-sometimes/70771>\
**Category:** Ignition\
**Created:** [March 8, 2023, 9:57am UTC](https://forum.inductiveautomation.com/t/expression-tag-is-slow-sometimes/70771 "2023-03-08T09:57:47Z")\
**Posts on this page:** 1\
**Showing post:** 14

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**Author:** ![lrose](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/lrose/32/62724_2.png) [@lrose](https://forum.inductiveautomation.com/u/lrose)\
**Post date:** [March 10, 2023, 7:29pm UTC](https://forum.inductiveautomation.com/t/expression-tag-is-slow-sometimes/70771/14 "2023-03-10T19:29:38Z")

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> [@grzegorz.kaczmarczyk](#):
>
> Do you have any idea, how to delay the start of the script for 50 ms?

Short answer, don't. If this is needed then you need to look at the system design.

See good advice here:

> [@Delay in Tag Event Script (Value Changed)](https://forum.inductiveautomation.com/t/delay-in-tag-event-script-value-changed/70666/6):
>
> In general, any delays of any kind are not acceptable in tag value change scripts, or any other tag event, due to the shared execution thread pool. Don't do it. You will bog down your tag infrastructure. Instead, design a state machine, perhaps with a timestamp in a memory tag, that is updated by a regular timer event. Do not use jython time, thread, or sleeping functionality in such events (or anywhere in Ignition, really).

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