# OPC UA Connection Failure with Siemens Sinumerik One

**URL:** <https://forum.inductiveautomation.com/t/opc-ua-connection-failure-with-siemens-sinumerik-one/89540>\
**Category:** Ignition\
**Tags:** perspective, ignition81\
**Created:** [April 26, 2024, 4:00pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-failure-with-siemens-sinumerik-one/89540 "2024-04-26T16:00:41Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Aditya\_Kulkarni](https://avatars.discourse-cdn.com/v4/letter/a/898d66/32.png) [@Aditya\_Kulkarni](https://forum.inductiveautomation.com/u/Aditya_Kulkarni)\
**Post date:** [April 26, 2024, 4:00pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-failure-with-siemens-sinumerik-one/89540/1 "2024-04-26T16:00:41Z")

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Hello All,

I have Ignition 8.1 connected with Siemens Sinumerik One NCU1750.  
I am using OPC Connections to fetch data from PLC.  
My connection status is connected .  
When there is new power cycle to PLC and Ignition PC the OPC communication shows as faulted.

 ![IMG20240425151215](https://us1.discourse-cdn.com/inductiveautomation/original/3X/0/8/08098a97ea66487755be1c158dd8230df0786f7a.jpeg)  
 ![IMG20240425162823](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/a/da77ca0fa86a84a8889df7db93d9b3880ebcf536.jpeg)  
 ![IMG20240425162745](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/5/957213c9ca247335870b292e7dae986df76e2fa6.jpeg)  
 ![IMG20240425162938](https://us1.discourse-cdn.com/inductiveautomation/original/3X/9/0/90a965e4b6aa058de187a9770e3f5d10a8e45983.jpeg)  
 ![IMG20240425162956](https://us1.discourse-cdn.com/inductiveautomation/original/3X/e/8/e8c8b61a800dc881c96a5f5517d509a5de5ebd9c.jpeg)

To make connection healthy I have to enter passwords in Sinumerik Authentication page and Reboot again .  
Then it comes up.  
It should be automatically connected all the time.

Is there any settings for this.

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**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:** [April 26, 2024, 4:14pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-failure-with-siemens-sinumerik-one/89540/2 "2024-04-26T16:14:57Z")

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Sounds like a Sinumerik question, not an Ignition question. Is there some procedure needed to save your authentication changes on the Sinumerik side to the Sinumerik's persistent memory?

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**Author:** ![Aditya\_Kulkarni](https://avatars.discourse-cdn.com/v4/letter/a/898d66/32.png) [@Aditya\_Kulkarni](https://forum.inductiveautomation.com/u/Aditya_Kulkarni)\
**Post date:** [April 26, 2024, 4:30pm UTC](https://forum.inductiveautomation.com/t/opc-ua-connection-failure-with-siemens-sinumerik-one/89540/3 "2024-04-26T16:30:15Z")

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May be ,Need to check this with siemens .