# Seek help on setting up an OPC UA tag connection to access data within DB in Siemens S7-300 PLC **URL:** \ **Category:** Ignition\ **Tags:** ignition83\ **Created:** [November 21, 2025, 8:01pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366 "2025-11-21T20:01:46Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 21, 2025, 8:01pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/1 "2025-11-21T20:01:46Z")
Hi folks, I am trying to establish a tag connection to access some data within a S7- 300 DB, and no success in getting it to work. It seems none of the syntax listed in the document here ([Siemens Enhanced Driver | Ignition User Manual](https://docs.inductiveautomation.com/docs/8.3/ignition-modules/opc-ua/opc-ua-drivers/siemens/siemens-enhanced-driver)) would never work for me… e.g. DB202.DBX24, DB202.X24.0, DB202.24, DB202.DBREAL24. Anybody has some insight to share? Would appreciate your help and thanks in advance. HW ---
**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, 2025, 8:06pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/2 "2025-11-21T20:06:38Z")
> [@hwang](#): > > e.g. DB202.DBX24, DB202.X24.0, DB202.24, DB202.DBREAL24. This isn't the syntax described in the manual... this is: `DB202,X24.0` Have you just got the wrong syntax or have you actually tried that as well? ---
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 21, 2025, 8:41pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/3 "2025-11-21T20:41:21Z")
Thanks Kevin for your quick response. I tested both cases, i.e. with a period sign AND with a comma as the separator as you mentioned here. Unfortunately, the results are the same. The diagnostics message is here: Error("CreateMonitoredItems failed: Bad\_NodeIdUnknown: The node id refers to a node that does not exist in the server address space.") FYI, accessing to the input and output points in the same PLC works fine. ---
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 21, 2025, 8:48pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/4 "2025-11-21T20:48:52Z")
![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/a/da51d8bf52caf3e9d85783076642e6cf3cc06ba0.png) I made a screen shot of the manual page fyi. ---
**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, 2025, 8:51pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/5 "2025-11-21T20:51:20Z")
Ah, are you actually using the new Siemens Enhanced driver, or the old one? ---
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 22, 2025, 12:10am UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/6 "2025-11-22T00:10:00Z")
Hi Kevin, I’ve used the new one, rev 8.3. Figured out that the appropriate syntax should be DB202, REAL24. Tested ok. Thank you again for your help. Have a great weekend. ---
**Author:** ![Cody\_Morgan](https://avatars.discourse-cdn.com/v4/letter/c/db5fbb/32.png) [@Cody\_Morgan](https://forum.inductiveautomation.com/u/Cody_Morgan)\ **Post date:** [November 22, 2025, 1:59am UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/7 "2025-11-22T01:59:49Z")
The syntaxes with the period should work with the Siemens Enhanced Driver. Are you sure you are not using the S7-300 driver? ---
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 22, 2025, 8:21pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/8 "2025-11-22T20:21:59Z")
Thanks Cody for pointing out. I forgot to mention that both the separators in my case all work well as I tested. ---
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 22, 2025, 8:22pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/9 "2025-11-22T20:22:54Z")
I have used the advanced driver . ---
**Author:** ![Cody\_Morgan](https://avatars.discourse-cdn.com/v4/letter/c/db5fbb/32.png) [@Cody\_Morgan](https://forum.inductiveautomation.com/u/Cody_Morgan)\ **Post date:** [November 24, 2025, 5:26pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/10 "2025-11-24T17:26:58Z")
Awesome. The Siemens Enhanced Driver was written to allow either the syntax of the older drivers, or the newer syntax that more closely matches what you would see in TIA. ---
**Author:** ![hwang](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@hwang](https://forum.inductiveautomation.com/u/hwang)\ **Post date:** [November 24, 2025, 5:40pm UTC](https://forum.inductiveautomation.com/t/seek-help-on-setting-up-an-opc-ua-tag-connection-to-access-data-within-db-in-siemens-s7-300-plc/112366/11 "2025-11-24T17:40:18Z")
Great feature and thanks for clarification from the design point!!!