# Indirect tag binding with an expression

**URL:** <https://forum.inductiveautomation.com/t/indirect-tag-binding-with-an-expression/49557>\
**Category:** Ignition\
**Created:** [August 4, 2021, 4:00pm UTC](https://forum.inductiveautomation.com/t/indirect-tag-binding-with-an-expression/49557 "2021-08-04T16:00:17Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![roger2](https://avatars.discourse-cdn.com/v4/letter/r/da6949/32.png) [@roger2](https://forum.inductiveautomation.com/u/roger2)\
**Post date:** [August 4, 2021, 4:00pm UTC](https://forum.inductiveautomation.com/t/indirect-tag-binding-with-an-expression/49557/1 "2021-08-04T16:00:17Z")

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I am wanting to use indirect / dynamic tag paths using an expression binding on an object but I keep getting an error message stating “Nested paths not allowed”. I have tried the following:

{[default]BBC\_Clgx/FermAuto/FermDrainVlvs/FermDropVlvAO+{RootContainer.FermValveNum}+“Select”} = 1  
and  
tag({[default]BBC\_Clgx/FermAuto/FermDrainVlvs/FermDropVlvAO+{Root Container.FermValveNum}+“Select”} = 1  
)

but get the same error message. Is there a way to assign a dynamic tag name in an expression binding?

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<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [August 4, 2021, 4:41pm UTC](https://forum.inductiveautomation.com/t/indirect-tag-binding-with-an-expression/49557/2 "2021-08-04T16:41:32Z")

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Yes, that would be the `tag()` expression function. But better to make a separate property indirectly bound, and use that in your comparison expression.

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<div class="post-metadata">

**Author:** ![wbaker](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/wbaker/32/85315_2.png) [@wbaker](https://forum.inductiveautomation.com/u/wbaker)\
**Post date:** [October 17, 2022, 6:12pm UTC](https://forum.inductiveautomation.com/t/indirect-tag-binding-with-an-expression/49557/3 "2022-10-17T18:12:17Z")

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This was helpful for me! Here is what my expression looked like, and it works as an Event Driven execution.

```auto
tag(concat({[.]Region},'/Setup/ContractDay'))

```

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<div class="post-metadata">

**Author:** ![Steve\_Laubach](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/steve_laubach/32/60900_2.png) [@Steve\_Laubach](https://forum.inductiveautomation.com/u/Steve_Laubach)\
**Post date:** [October 17, 2022, 7:49pm UTC](https://forum.inductiveautomation.com/t/indirect-tag-binding-with-an-expression/49557/4 "2022-10-17T19:49:20Z")

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Note what @pturmel said.

It's a good idea to add a custom property and populate it with an indirect tag binding bind. You can reference that value in an expression using a property binding if needed and write to it by making it bidirectional. I believe indirect bindings are faster than expression bindings.

Correct me if I'm wrong but I'm pretty sure that's correct. It is what I do.