# OPC write-back settings available for Expression Tags is missing

**URL:** <https://forum.inductiveautomation.com/t/opc-write-back-settings-available-for-expression-tags-is-missing/51284>\
**Category:** Ignition\
**Created:** [September 23, 2021, 8:10pm UTC](https://forum.inductiveautomation.com/t/opc-write-back-settings-available-for-expression-tags-is-missing/51284 "2021-09-23T20:10:53Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![witman](https://avatars.discourse-cdn.com/v4/letter/w/d2c977/32.png) [@witman](https://forum.inductiveautomation.com/u/witman)\
**Post date:** [September 23, 2021, 8:13pm UTC](https://forum.inductiveautomation.com/t/opc-write-back-settings-available-for-expression-tags-is-missing/51284/3 "2021-09-23T20:13:37Z")

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> [@\[13069\] - Write value to Opc item feature for Expression Tags is no longer available in 8.0](https://forum.inductiveautomation.com/t/13069-write-value-to-opc-item-feature-for-expression-tags-is-no-longer-available-in-8-0/23112/5):
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> This functionality as it was in 7.9 is not coming back. Tags that had an OPC write-back defined now get a special “Legacy Value Changed” entry in the Tag Event Scripts: Tags that you want to add this functionality to should just use the regular Value Changed event to invoke system.opc.writeValue.

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