Write target of item '......' does not exist problem

Inductive Automation Team,

We have Standard Transaction Group in our Project where update mode is DB to OPC. We have following sample Transaction Group structure:
Item Name(OPS Tag) Target Name(DB Fields from Single table)
OPC_Mod1_WONum <-- WONum
OPC_Mod1_Bit1 <-- Mod1_Bit1
OPC_Mod2_WONum <-- WONum
OPC_Mod2_Bit1 <-- Mod2_Bit1
OPC_Mod2_Bit2 <-- Mod2_Bit2

As shown above, for OPC Mod1/Mod2 WONum the target name is same DB Field from Table. Now, we are facing Write target of item ‘Mod2_WONum’ does not exist. problem. Is it due to using same Target Name (same DB field) from Table? if not, how to resolve this issue?

Eagerly waiting for your response.

Hi Sasi,

Transaction Groups can behave oddly when duplicating items. Try adding an expression item That is equal to WONum, write to OPC_Mod2_WONum, and see if that helps.



Thank you for your reply. As you mentioned, we currently used Expression Item and seems to be working fine.

Just for learning, do you have any explanation for duplicating items issue.

Nope. No clue. :laughing: Although maybe some suspicions…

I suspect it is looking things up in a “first come, first serve” basis. Once it finds the first thing it sees to write back to, it just won’t look any further.

I think it may have been put in as a feature request once upon a time.

Thank you Jordan.