# Write back to same MQTT tag

**URL:** <https://forum.inductiveautomation.com/t/write-back-to-same-mqtt-tag/89926>\
**Category:** Maker\
**Tags:** ignition81, perspective\
**Created:** [May 4, 2024, 10:09pm UTC](https://forum.inductiveautomation.com/t/write-back-to-same-mqtt-tag/89926 "2024-05-04T22:09:26Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Vidar\_Hetlelid](https://avatars.discourse-cdn.com/v4/letter/v/dfb087/32.png) [@Vidar\_Hetlelid](https://forum.inductiveautomation.com/u/Vidar_Hetlelid)\
**Post date:** [May 4, 2024, 10:09pm UTC](https://forum.inductiveautomation.com/t/write-back-to-same-mqtt-tag/89926/1 "2024-05-04T22:09:26Z")

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Hello,

Using MQTT engine i get all my tags easily. But i want to be able to write back to the same tag. Is it possible to do that? If so, how can I do that? It says that the tag is read-only.

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**Author:** ![Kevin.Collins](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.collins/32/13497_2.png) [@Kevin.Collins](https://forum.inductiveautomation.com/u/Kevin.Collins)\
**Post date:** [May 5, 2024, 12:23am UTC](https://forum.inductiveautomation.com/t/write-back-to-same-mqtt-tag/89926/2 "2024-05-05T00:23:54Z")

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If these are coming from SparkplugB, then you should be able to just [enable outbound writes](https://docs.chariot.io/display/CLD80/Enable+Device+Writes+from+Ignition) in the MQTT Engine settings (they are disabled by default). If it is a custom namespace and plain MQTT topics, then I believe you have to do those via scripting functions such as [system.cirruslink.engine.publish](https://docs.chariot.io/display/CLD80/ME%3A+Python+Scripting#ME:PythonScripting-publish).

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<div class="post-metadata">

**Author:** ![Vidar\_Hetlelid](https://avatars.discourse-cdn.com/v4/letter/v/dfb087/32.png) [@Vidar\_Hetlelid](https://forum.inductiveautomation.com/u/Vidar_Hetlelid)\
**Post date:** [May 6, 2024, 8:36pm UTC](https://forum.inductiveautomation.com/t/write-back-to-same-mqtt-tag/89926/3 "2024-05-06T20:36:25Z")

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Thanks. I want to learn about sparkplug, and how its done in the industry. Is it normal that i.e PLC publish its current setpoint, and that Ignition write back to the same tag, if I want to change the value? Or is there another practical way of doing this?

Also, when I try writing back, it automatically gets overwritten as you see below... 😕

![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/6/a/6a46fe6324cd0fedacaabf542412c8a6199018f8.png)

![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/2/f20bb05f6189ed37065ecaa32584493a7202e9cb.png)

I have enabled outbound tag write also  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/c/dcd6dab77b85af4970ebac1a7e431cfe358a5110.png)

Any ideas?