# Write a value to Master UDT Parameter

**URL:** <https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234>\
**Category:** Ignition\
**Created:** [July 30, 2020, 6:49pm UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234 "2020-07-30T18:49:52Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![suram-in](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/suram-in/32/51348_2.png) [@suram-in](https://forum.inductiveautomation.com/u/suram-in)\
**Post date:** [July 30, 2020, 6:49pm UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234/1 "2020-07-30T18:49:52Z")

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Hi All,

I am using Ignition Version 8.0.15.

I want to write a Value to a Master UDT parameter from a Tag.

Thanks in Advance,  
Suresh

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**Author:** ![edward.fowler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/edward.fowler/32/24179_2.png) [@edward.fowler](https://forum.inductiveautomation.com/u/edward.fowler)\
**Post date:** [October 26, 2022, 3:44am UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234/2 "2022-10-26T03:44:24Z")

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Hi.  
Did you find a way to do it?  
Thanks.

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<div class="post-metadata">

**Author:** ![suram-in](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/suram-in/32/51348_2.png) [@suram-in](https://forum.inductiveautomation.com/u/suram-in)\
**Post date:** [October 26, 2022, 4:41am UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234/3 "2022-10-26T04:41:03Z")

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Hi Edward,

I have used the Tag Event Script to write the value to UDT parameter.

system.tag.write("[.]/Parameters.Value\_Change", "5.5")

Thanks,  
Suresh

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<div class="post-metadata">

**Author:** ![edward.fowler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/edward.fowler/32/24179_2.png) [@edward.fowler](https://forum.inductiveautomation.com/u/edward.fowler)\
**Post date:** [October 26, 2022, 5:02am UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234/4 "2022-10-26T05:02:56Z")

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Hi Suresh,  
Thank you for the reply.  
It seems like you're writing to an instance parameter. I'm actually trying to write to the data type parameter. I can do that, but I can't seem to get a value from it in the instance.  
I'll keep hacking away at it 🙂  
Regards,  
Ted.

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<div class="post-metadata">

**Author:** ![suram-in](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/suram-in/32/51348_2.png) [@suram-in](https://forum.inductiveautomation.com/u/suram-in)\
**Post date:** [October 26, 2022, 5:29am UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234/5 "2022-10-26T05:29:32Z")

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Hi Ted,

system.tag.write("[.]/Parameters.Value\_Change", "5.5"). This code I have written in the UDT Definition. The Value 5.5 varies for me instance to instance. So I use system.tag.write("[.]/Parameters.Value\_Change", pvvalue)

Are you trying to push the value in UDT definition parameter and that reflects to all the instances? I hope I understand the requirement correctly.

If not, share some examples with screenshot, it will be helpful to understand.

Thanks,  
Suresh

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<div class="post-metadata">

**Author:** ![edward.fowler](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/edward.fowler/32/24179_2.png) [@edward.fowler](https://forum.inductiveautomation.com/u/edward.fowler)\
**Post date:** [October 26, 2022, 3:00pm UTC](https://forum.inductiveautomation.com/t/write-a-value-to-master-udt-parameter/37234/6 "2022-10-26T15:00:27Z")

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> [@suram-in](#):
>
> Are you trying to push the value in UDT definition parameter and that reflects to all the instances? I hope I understand the requirement correctly.

Hi Suresh,  
Yes, I am, and its working. The only thing is the parameter values in the tag browser don't update for the instances.