# Error creating dynamic tags

**URL:** <https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375>\
**Category:** Ignition\
**Created:** [November 22, 2025, 2:05pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375 "2025-11-22T14:05:00Z")\
**Posts on this page:** 9\
**Page:** 1

<div class="post-metadata">

**Author:** ![deepti\_k](https://avatars.discourse-cdn.com/v4/letter/d/3be4f8/32.png) [@deepti\_k](https://forum.inductiveautomation.com/u/deepti_k)\
**Post date:** [November 22, 2025, 2:05pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/1 "2025-11-22T14:05:00Z")

</div>

I am trying to create a UDT tag dynamically inside one of the existing tags, but it is not working.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/8/e8537fabfb440814e241044c08428608343ba3a5.png)

tagPath="[default]test"  
#name="cook"

```python
# 1) Create the UDT instance from the DEFINITION, not the internal _types_ path
system.tag.configure(tagPath, [{
    "name": "cook",
    "type": "UDT_INST",
    "udtTypeId": "test", # <= use the UDT definition path
    "enabled": True
}], "o")

It is not working; it creates the UDT but does not create the child tags inside.

```

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/1/61e63707e8a2725f6e2ed95cd518acd549f4d0a4.png)

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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:** [November 22, 2025, 2:27pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/2 "2025-11-22T14:27:05Z")

</div>

You cannot. UDT structures are fixed.

If you need variant structures, you typically need to use a regular tag folder. (Though you might make multiple UDTs from a base UDT.)

---

<div class="post-metadata">

**Author:** ![deepti\_k](https://avatars.discourse-cdn.com/v4/letter/d/3be4f8/32.png) [@deepti\_k](https://forum.inductiveautomation.com/u/deepti_k)\
**Post date:** [November 22, 2025, 2:43pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/3 "2025-11-22T14:43:35Z")

</div>

I know UDT structures are fixed. I am trying to get a UDT into a normal tag

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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:** [November 22, 2025, 2:52pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/4 "2025-11-22T14:52:54Z")

</div>

Ok. Might be a bug. I don't recall seeing anything like this, so you probably want to open a support ticket.

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<div class="post-metadata">

**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [November 22, 2025, 11:56pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/5 "2025-11-22T23:56:36Z")

</div>

> [@deepti\_k](#):
>
> ```python
> "type": "UDT_INST",
> "udtTypeId": "test",
> 
> ```

I don’t know where you got these from, but I suggest you create a UDT instance manually and check its json. The type should be `"tagType": "UdtInstance"` and use `"typeId”: ”test” `

On second thoughts, I'll bet this came from AI

Your original code is just creating a memory tag with those two added custom props in it

---

<div class="post-metadata">

**Author:** ![deepti\_k](https://avatars.discourse-cdn.com/v4/letter/d/3be4f8/32.png) [@deepti\_k](https://forum.inductiveautomation.com/u/deepti_k)\
**Post date:** [November 23, 2025, 4:22am UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/6 "2025-11-23T04:22:36Z")

</div>

> [@nminchin](#):
>
> "tagType": "UdtInstance"

tagPath="[default]test"  
#name="cook"

# 1) Create the UDT instance from the DEFINITION, not the internal \_types\_ path  
system.tag.configure(tagPath, [{  
"name": "cook",  
"tagType": "UdtInstance",  
"UdtType": "test", # \<= use the UDT definition path  
"enabled": True  
}], "o")

I am getting parent data type doesn’t exists

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/8/a/8abd6d702b6bacea4fc077a076adede7ffc07a10.png)

---

<div class="post-metadata">

**Author:** ![nminchin](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/nminchin/32/6911_2.png) [@nminchin](https://forum.inductiveautomation.com/u/nminchin)\
**Post date:** [November 23, 2025, 4:48am UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/7 "2025-11-23T04:48:01Z")

</div>

> [@nminchin](#):
>
> and use `"typeId”: ”test”`

You ignored this part, and for some reason you renamed

> [@deepti\_k](#):
>
> `udtTypeId`

To

> [@deepti\_k](#):
>
> UdtType

When I said

> [@nminchin](#):
>
> use `"typeId”: ”test”`

---

<div class="post-metadata">

**Author:** ![deepti\_k](https://avatars.discourse-cdn.com/v4/letter/d/3be4f8/32.png) [@deepti\_k](https://forum.inductiveautomation.com/u/deepti_k)\
**Post date:** [November 23, 2025, 5:04am UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/8 "2025-11-23T05:04:34Z")

</div>

> [@nminchin](#):
>
> UdtInstance

yes it’s working..Thank you

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<div class="post-metadata">

**Author:** ![pascal.fragnoud](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pascal.fragnoud/32/24728_2.png) [@pascal.fragnoud](https://forum.inductiveautomation.com/u/pascal.fragnoud)\
**Post date:** [November 23, 2025, 5:46pm UTC](https://forum.inductiveautomation.com/t/error-creating-dynamic-tags/112375/9 "2025-11-23T17:46:15Z")

</div>

> [@nminchin](#):
>
> I don’t know where you got these from

That's a typical LLM mistake.