# Echo Tag Value back to OPC tag

**URL:** <https://forum.inductiveautomation.com/t/echo-tag-value-back-to-opc-tag/93854>\
**Category:** Ignition\
**Tags:** scripting\
**Created:** [July 29, 2024, 5:56pm UTC](https://forum.inductiveautomation.com/t/echo-tag-value-back-to-opc-tag/93854 "2024-07-29T17:56:12Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![David\_Bartel](https://avatars.discourse-cdn.com/v4/letter/d/58f4c7/32.png) [@David\_Bartel](https://forum.inductiveautomation.com/u/David_Bartel)\
**Post date:** [July 29, 2024, 5:56pm UTC](https://forum.inductiveautomation.com/t/echo-tag-value-back-to-opc-tag/93854/1 "2024-07-29T17:56:12Z")

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I new at ignition and I'm trying to create a script for an OPC tag using the ValueChanged script. I'm completely lost. I don't know if I have my Path right, or anything. I figured out how to look at the log and have seen a variety of errors as I try different things.  
Is there some script out there that already does this?

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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:** [July 29, 2024, 6:01pm UTC](https://forum.inductiveautomation.com/t/echo-tag-value-back-to-opc-tag/93854/2 "2024-07-29T18:01:41Z")

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You mean send incoming values on one tag (OPC, presumably) to a different OPC tag?

Perhaps the techniques here will help you:

> [@Modbus Slave/Server to Generate Read Only Tags](https://forum.inductiveautomation.com/t/modbus-slave-server-to-generate-read-only-tags/87583/21):
>
> I've create a generic "Modbus Publish" script that eliminates the need for a second set of tags. I've publicly posted it here: [https://www.automation-pros.com/ignition/modbusPublish.py](https://www.automation-pros.com/ignition/modbusPublish.py) It requires the "Queue Utility" script posted here: [https://www.automation-pros.com/ignition/queueUtil.py](https://www.automation-pros.com/ignition/queueUtil.py) and described over here: Both scripts rely on my Integration Toolkit's globalVarMap() script function, but you can rework that (not quite 1:1) to use system.util.getGlobals() if you must. (Not recomme…

(Whatever you do, don't use `system.tag.writeBlocking()` or `system.opc.writeValues()` in a tag's `valueChange` event.)