# Ns=2;s= in front of OPC Item Path?

**URL:** <https://forum.inductiveautomation.com/t/ns-2-s-in-front-of-opc-item-path/16085>\
**Category:** Ignition\
**Tags:** ignition79\
**Created:** [November 21, 2017, 11:17pm UTC](https://forum.inductiveautomation.com/t/ns-2-s-in-front-of-opc-item-path/16085 "2017-11-21T23:17:40Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![JT1](https://avatars.discourse-cdn.com/v4/letter/j/e9bcb4/32.png) [@JT1](https://forum.inductiveautomation.com/u/JT1)\
**Post date:** [November 21, 2017, 11:17pm UTC](https://forum.inductiveautomation.com/t/ns-2-s-in-front-of-opc-item-path/16085/1 "2017-11-21T23:17:40Z")

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Hi,

I set up a OPC-UA type connection in Ignition to connect to KEPServer EX V6. The previous configuration is OPC-DA COM connection to KEPServer EX V5.

However, now all the OPC tags need to have “ns=2;s=” as a prefix of their OPC Item Paths. The OPC tags would have “Config Error” without this prefix.

Has anyone encountered this and know what “ns=2;s=” mean? The Ignition version I’m using is 7.9.4.

Thanks!  
JT

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<div class="post-metadata">

**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\
**Post date:** [November 21, 2017, 11:24pm UTC](https://forum.inductiveautomation.com/t/ns-2-s-in-front-of-opc-item-path/16085/2 "2017-11-21T23:24:19Z")

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When an OPC tag belongs to an OPC UA connection, the OPC Item Path is specifying the NodeId.

That prefix specifies the namespace index a NodeId belongs to.

For weird historical reasons, we assume ns=1 if it’s not explicitly present. Kepware’s Nodes are all in ns=2, so, it must be specified.