# Ignition Multiple OPC Tags

**URL:** <https://forum.inductiveautomation.com/t/ignition-multiple-opc-tags/61961>\
**Category:** Ignition\
**Tags:** ignition81\
**Created:** [July 15, 2022, 5:10pm UTC](https://forum.inductiveautomation.com/t/ignition-multiple-opc-tags/61961 "2022-07-15T17:10:28Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Carlos\_Dominguez](https://avatars.discourse-cdn.com/v4/letter/c/df788c/32.png) [@Carlos\_Dominguez](https://forum.inductiveautomation.com/u/Carlos_Dominguez)\
**Post date:** [July 15, 2022, 5:10pm UTC](https://forum.inductiveautomation.com/t/ignition-multiple-opc-tags/61961/1 "2022-07-15T17:10:28Z")

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Hello Guys

I have 4 PLC’s connected to ignition.  
I want to create a tag into Ignition to modify the same 4 tags each one.  
Is there a option to do this? Thanks!

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<div class="post-metadata">

**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\
**Post date:** [July 15, 2022, 5:21pm UTC](https://forum.inductiveautomation.com/t/ignition-multiple-opc-tags/61961/2 "2022-07-15T17:21:58Z")

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The tags will be independent. They have to be because they’ll be on four independent device connections.

Presumably you want a common component to control the same tag in each of the four controllers. To do you could:

- Add a numeric field component to your view (Perspective) or window (Vision).
- Add an onChange event script to that component.
- Have the script update the tag in each of the PLCs.

See [system.tag.writeBlocking - Ignition User Manual 8.1 - Ignition Documentation](https://docs.inductiveautomation.com/display/DOC81/system.tag.writeBlocking).

You put the four tag paths into `paths` list. You put the value to be written into the `values` list four times. e.g.,

```auto
# Create a list with the tag paths to be updated.
paths = ["[default]Folder/Tag_A","[default]Folder/Tag_B",
         "[default]Folder/Tag_C","[default]Folder/Tag_D"]
 
# Create a list with the update values, one value for each path.
v = <get value from component>
values = [v, v, v, v]
 
# Execute the write operation.
system.tag.writeBlocking(paths, values)

```

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<div class="post-metadata">

**Author:** ![Carlos\_Dominguez](https://avatars.discourse-cdn.com/v4/letter/c/df788c/32.png) [@Carlos\_Dominguez](https://forum.inductiveautomation.com/u/Carlos_Dominguez)\
**Post date:** [July 21, 2022, 3:31pm UTC](https://forum.inductiveautomation.com/t/ignition-multiple-opc-tags/61961/3 "2022-07-21T15:31:56Z")

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Thx!