# Siemens OPC UA Variable déclaration in Edge **URL:** \ **Category:** Ignition\ **Tags:** perspective\ **Created:** [November 29, 2024, 9:41am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255 "2024-11-29T09:41:31Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Thomas\_MUSSO](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@Thomas\_MUSSO](https://forum.inductiveautomation.com/u/Thomas_MUSSO)\ **Post date:** [November 29, 2024, 9:41am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/1 "2024-11-29T09:41:31Z")
Hello, I hope you are well ! I would just like to declare the OPC Item Path in a tag coming from a Siemens. Example: Name of my device: `API Puisard` Data Siemens Adress: `DB21.DBD16` (its a Udint, so I try in Ignition with INT type, then Long type) (I use this OPC Connection:` Ignition OPC UA Server`, with a remote provider [`Data_Edge`]) I tried something like `[API Puisard]DB21.DBD16` Then `[API Puisard]DB21,DBD16` ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/2/1/2172885bab63c0f87413d21c3f79470aee03ec74.png) But it still doesn't work, can you help me? Thanks in advance! ---
**Author:** ![Arnaud\_Declerck](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/arnaud_declerck/32/44872_2.png) [@Arnaud\_Declerck](https://forum.inductiveautomation.com/u/Arnaud_Declerck)\ **Post date:** [November 29, 2024, 9:54am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/2 "2024-11-29T09:54:21Z")
Hi @Thomas_MUSSO , sometimes just reading the manual can learn you a lot 😉 > **[Siemens | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/opc-ua/opc-ua-drivers/siemens#configuring-siemens-addressing)** > > The Siemens drivers in Ignition support basic connections to S7 devices. Ignition connects to these PLCs via TCP/IP using the S7 protocol. Similar to Modbus and some Allen Bradley connections, the Siemens S7 devices do not support tag browsing. You... ---
**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\ **Post date:** [November 29, 2024, 10:12am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/3 "2024-11-29T10:12:48Z")
> [@Arnaud\_Declerck](#): > > [Siemens | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/opc-ua/opc-ua-drivers/siemens#configuring-siemens-addressing) This one is not in the manual... @Thomas_MUSSO I believe that the correct address is: `[API Puisard]DB21,D16` For some reason siemens adds the `DB` in front of a bunch of data types. You would change the `D` in `D16` to match the data type you are reading from the PLC, so `REAL16` if it was a float. ---
**Author:** ![Arnaud\_Declerck](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/arnaud_declerck/32/44872_2.png) [@Arnaud\_Declerck](https://forum.inductiveautomation.com/u/Arnaud_Declerck)\ **Post date:** [November 29, 2024, 10:36am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/4 "2024-11-29T10:36:39Z")
Correct but at least it give you the correct way to make your addressing. DBXXX,DataTypeXXX I've just checked in one of my project and we use the dword to read a UDINT so the [API Puisard]DB21,D16 should work. In Ignition we used data type long. ---
**Author:** ![Thomas\_MUSSO](https://avatars.discourse-cdn.com/v4/letter/t/b9e5f3/32.png) [@Thomas\_MUSSO](https://forum.inductiveautomation.com/u/Thomas_MUSSO)\ **Post date:** [November 29, 2024, 10:59am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/5 "2024-11-29T10:59:53Z")
Thank you for your reply Arnaud and David. Concerning Float, addressing `[API Puisard]DB21,REAL16` seems to work. Thanks ! However for UDINT (Ignition Data Type on “Long”), I try `[API Puisard]DB21,DWORD16` -\> don't work. Then, for my BOOL, I try `[API Puisard]DB21,DBX16.0` -\> don't work. I'll try to find out why. If you have any other ideas, I'd love to hear from you. ---
**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 29, 2024, 2:35pm UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/6 "2024-11-29T14:35:59Z")
> [@Thomas\_MUSSO](#): > > Then, for my BOOL, I try `[API Puisard]DB21,DBX16.0` -\> don't work. It should be `[API Puisard]DB21,X16.0`. There is never a redundant "DB" in the address with this driver. ---
**Author:** ![David\_Stone](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/david_stone/32/79749_2.png) [@David\_Stone](https://forum.inductiveautomation.com/u/David_Stone)\ **Post date:** [November 30, 2024, 1:28am UTC](https://forum.inductiveautomation.com/t/siemens-opc-ua-variable-declaration-in-edge/99255/7 "2024-11-30T01:28:34Z")
> [@Thomas\_MUSSO](#): > > However for UDINT (Ignition Data Type on “Long”), I try `[API Puisard]DB21,DWORD16` -\> don't work. `[API Puisard]DB21,D16`