# OPC-DA OPCItemPaths

**URL:** <https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779>\
**Category:** Ignition\
**Created:** [March 4, 2024, 5:03pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779 "2024-03-04T17:03:59Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![mmunin](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mmunin](https://forum.inductiveautomation.com/u/mmunin)\
**Post date:** [March 4, 2024, 5:03pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779/1 "2024-03-04T17:03:59Z")

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I’m attempting to bridge a “legacy” scada system with Igntition via the legacy system’s built in OPC-DA server.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/b/d/bd54e3d8131a2e8b419f087bb2e22b03cc15074c.png)

Both Ignition and the OPC Server are running on my Windows workstation. A third party OPC-DA client, MatrikonOPC Explorer, can successfully read data from the OPC-DA Server.

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/7/b/7b51897833b55885305306de1833c5cc2147d521.jpeg)

However, using the exact same item path I use in MatrikonOPC for OpcItemPath, Ignition logs a “c0040008” error, which means “The item ID doesn't conform to the server's syntax.”

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/a/3/a3de3bbcee133c4e68781cf3bba4c27eed58aed8.png)

I’m hoping that, similar to OPCUA, I need to prepend something akin to “ns=0;s=” to my OpcItemPath property in my ignition tag? Does anyone here have experience with OPC-DA ever run into anything similar?

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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:** [March 4, 2024, 5:16pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779/2 "2024-03-04T17:16:56Z")

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Are you creating this tag manually or by drag n drop from the OPC browser?

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<div class="post-metadata">

**Author:** ![mmunin](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mmunin](https://forum.inductiveautomation.com/u/mmunin)\
**Post date:** [March 4, 2024, 5:19pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779/3 "2024-03-04T17:19:36Z")

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Manually. My OPC Server doesn't support browsing.

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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:** [March 4, 2024, 5:20pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779/4 "2024-03-04T17:20:32Z")

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Hmm, well if there's a prefix it's not standardized, it's specific to that server. I don't know if Matrikon explorer is implicitly adding a prefix or not.

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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:** [March 4, 2024, 5:23pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779/5 "2024-03-04T17:23:12Z")

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FWIW, the OPC Item Path you used in Ignition appears to end with `_INT`, while in your screenshot from Matrikon Explorer it ends with `_TOP`. You're not doing yourself any favors by censoring the very thing we're troubleshooting.

You can call support if this information is really that proprietary that you can't show it here.

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<div class="post-metadata">

**Author:** ![mmunin](https://avatars.discourse-cdn.com/v4/letter/m/c0e974/32.png) [@mmunin](https://forum.inductiveautomation.com/u/mmunin)\
**Post date:** [March 4, 2024, 10:24pm UTC](https://forum.inductiveautomation.com/t/opc-da-opcitempaths/86779/6 "2024-03-04T22:24:13Z")

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It ended up being an issue with windows securities on the OPC server itself! Had to run Ignition as a proper domain user.

Thanks for letting me know the prefix thing was a red herring, helped me focus what to look for. Sorry for the mismatched tags, had to change everything to see if I could make it work before asking here.

Thanks