# Tag Property Nested Parameter Binding

**URL:** <https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [December 19, 2025, 4:39pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918 "2025-12-19T16:39:34Z")\
**Posts on this page:** 12\
**Page:** 1

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**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [December 19, 2025, 4:39pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/1 "2025-12-19T16:39:34Z")

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Is this going to work to have a parameter binding offset bound to another parameter?

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/b/a/ba080b34daac92a73a0a805c5ba9e3070f37081a.png)

```python
ns=1;s=[{Device_ascpt}]{Legacy_ascpt}SLUDGE_STG_ANALOGS{Analogs_ascpt}[{Hr_Index_ascpt+{Hr_Mn_Offset_ascpt}}]

```

If not, how do I do this? Sometimes it’s +10, other times it’s +6

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<div class="post-metadata">

**Author:** ![vtran](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vtran](https://forum.inductiveautomation.com/u/vtran)\
**Post date:** [December 19, 2025, 5:04pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/2 "2025-12-19T17:04:42Z")

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> [@amarks](#):
>
> `{Hr_Index_ascpt+{Hr_Mn_Offset_ascpt}}`

should just be `{Hr_Index_ascpt + Hr_Mn_Offset_ascpt}`, I think. No need for nested curly braces

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<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [December 19, 2025, 5:07pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/3 "2025-12-19T17:07:12Z")

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No, I just get a general config error with that

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<div class="post-metadata">

**Author:** ![Samuel\_Sueur](https://avatars.discourse-cdn.com/v4/letter/s/e36b37/32.png) [@Samuel\_Sueur](https://forum.inductiveautomation.com/u/Samuel_Sueur)\
**Post date:** [December 19, 2025, 5:17pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/4 "2025-12-19T17:17:40Z")

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Not sure but this might work:

```python
{"Hr_Index_ascpt" + "Hr_Mn_Offset_ascpt"}

```

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<div class="post-metadata">

**Author:** ![vtran](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vtran](https://forum.inductiveautomation.com/u/vtran)\
**Post date:** [December 19, 2025, 5:21pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/5 "2025-12-19T17:21:10Z")

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Weird, seems to work fine for me

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/1/61a7441494bd53b3bcd059161b7351caebdf4063.png)

try `{Hr_Index_ascpt}` and `{Hr_Mn_Offset_ascpt}` in your binding by themself and see if you get the parameter value by them self at all?

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<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [December 19, 2025, 5:23pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/6 "2025-12-19T17:23:58Z")

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Ok, ya it worked. By binding on the parent UDT was messed up. Thanks!

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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:** [December 19, 2025, 9:27pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/7 "2025-12-19T21:27:37Z")

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Wait, so this works?

> [@vtran](#):
>
> work fine for me
> 
> ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/1/61a7441494bd53b3bcd059161b7351caebdf4063.png)

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<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [December 19, 2025, 9:43pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/8 "2025-12-19T21:43:33Z")

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yes

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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:** [December 19, 2025, 9:44pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/9 "2025-12-19T21:44:48Z")

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Nice! I never knew this was possible

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<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [December 19, 2025, 10:31pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/10 "2025-12-19T22:31:26Z")

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UDT parameter "bindings" like this are _weird_. They run way before anything else in the stack, essentially by doing literal string replacement on the raw configuration, before _anything_ has had a chance to run.  
This is both powerful, and headache inducing (see the ~bimonthly posts where someone asks why they can't use `"{}".format()` in a UDT script). 🤷

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<div class="post-metadata">

**Author:** ![amarks](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/amarks/32/45610_2.png) [@amarks](https://forum.inductiveautomation.com/u/amarks)\
**Post date:** [December 19, 2025, 10:43pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/11 "2025-12-19T22:43:06Z")

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everyone just ignores this, myself included 😄

![image](https://us1.discourse-cdn.com/inductiveautomation/optimized/3X/1/9/191785928e671759540856749dd2b4e741639def_2_690x82.png)

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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:** [December 19, 2025, 11:14pm UTC](https://forum.inductiveautomation.com/t/tag-property-nested-parameter-binding/112918/12 "2025-12-19T23:14:45Z")

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I’d forgotten about that one. I think it’s only an issue if you put names inside the braces e.g. `“{0}”.format(…)` compared to `"{}”.format(…)`

I got Claude to find relevant posts for an example:

> [@Python String Formatting in Tag Change Script](https://forum.inductiveautomation.com/t/python-string-formatting-in-tag-change-script/70855):
>
> It seems like pythonic string formatting is broken within tag-change event scripts. For example, writing value = currentValue.value ack\_value = "{0}\_ACK".format(str(value)) # unnecessary str() call, but used for comparison only does not work, but value = currentValue.value ack\_value = str(value) + "\_ACK" does. We get no errors on the gateway and cannot run any code above or below the str().format() call until it is removed. Is the Jython environment within the tag-change script a diff…