# Derived tags quality from source

**URL:** <https://forum.inductiveautomation.com/t/derived-tags-quality-from-source/30325>\
**Category:** Ignition\
**Created:** [November 29, 2019, 1:48pm UTC](https://forum.inductiveautomation.com/t/derived-tags-quality-from-source/30325 "2019-11-29T13:48:11Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mohamad.tayara](https://avatars.discourse-cdn.com/v4/letter/m/977dab/32.png) [@mohamad.tayara](https://forum.inductiveautomation.com/u/mohamad.tayara)\
**Post date:** [November 29, 2019, 1:48pm UTC](https://forum.inductiveautomation.com/t/derived-tags-quality-from-source/30325/1 "2019-11-29T13:48:11Z")

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Hello,  
I am using ignition to connect to a Siemens S7 1500 CPU using the integrated OPC UA server, in my PLC I have a datatype with nested UDTs (around 100 atomic vaiables) so i have used the derived tag method described in another post in this forum: [http://forum.inductiveautomation.com/t/opc-ua-struct-data-type/26905](http://forum.inductiveautomation.com/t/opc-ua-struct-data-type/26905): ,in order to optimize the communication with the Siemens PLC. The method is working great, but the only issue is the quality of the derived tag will go to invalid expression instead of Bad\_unconnected when i loose the communication with the PLC, is there a way to transfer the quality of the source tag to the derived tag. thanks in advance.