# I/O signals not showing in OPC UA client

**URL:** <https://tech-community.robotics.abb.com/t/i-o-signals-not-showing-in-opc-ua-client/11872>\
**Category:** OmniCore\
**Tags:** opc-ua-client, opcuaclient, opc-ua\
**Created:** [April 7, 2025, 8:59pm UTC](https://tech-community.robotics.abb.com/t/i-o-signals-not-showing-in-opc-ua-client/11872 "2025-04-07T20:59:01Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![poiuyt](https://avatars.discourse-cdn.com/v4/letter/p/c67d28/32.png) [@poiuyt](https://tech-community.robotics.abb.com/u/poiuyt)\
**Post date:** [April 7, 2025, 8:59pm UTC](https://tech-community.robotics.abb.com/t/i-o-signals-not-showing-in-opc-ua-client/11872/1 "2025-04-07T20:59:01Z")

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I managed to establish connection between Robotstudio and UAexpert the OPC UA client I am currently using. The problem is that whenever I go in to the I/O signals folder in the OPC UA client, there are no signals or tags that is showing up. It’s just empty

I’ve already tried to read and write to the virtual controller in I/O engineering. I also tried restarting the controller but that still does not fix the issue. What might be the problem?

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**Author:** ![poiuyt](https://avatars.discourse-cdn.com/v4/letter/p/c67d28/32.png) [@poiuyt](https://tech-community.robotics.abb.com/u/poiuyt)\
**Post date:** [April 8, 2025, 7:56am UTC](https://tech-community.robotics.abb.com/t/i-o-signals-not-showing-in-opc-ua-client/11872/2 "2025-04-08T07:56:38Z")

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Nevermind, got the issue resolved

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**Author:** ![Paul\_Grayson](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@Paul\_Grayson](https://tech-community.robotics.abb.com/u/Paul_Grayson)\
**Post date:** [July 1, 2025, 11:50am UTC](https://tech-community.robotics.abb.com/t/i-o-signals-not-showing-in-opc-ua-client/11872/3 "2025-07-01T11:50:54Z")

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How did you resolve your issue?

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<div class="post-metadata">

**Author:** ![poiuyt](https://avatars.discourse-cdn.com/v4/letter/p/c67d28/32.png) [@poiuyt](https://tech-community.robotics.abb.com/u/poiuyt)\
**Post date:** [November 5, 2025, 10:59am UTC](https://tech-community.robotics.abb.com/t/i-o-signals-not-showing-in-opc-ua-client/11872/4 "2025-11-05T10:59:22Z")

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> [@Paul\_Grayson](#):
>
> How did you resolve your issue?

Sorry for late response

I realized that both OPC in Robotstudio and the UAexpert are clients and as I understand it, it’s not possible to connect client to client, which might explain why the I/O does not appear at the other end. Only clients to servers. So I used Siemens TIA portal V18 which has OPC UA servers to connect with the Robotstudio OPC UA client which worked.